c 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 10.1002/14356007.f16 f01 Dry Mortars 1 Dry Mortars Roland Bayer, Wolff Cellulosics GmbH & Co KG, D-29699 Bomlitz, Germany Hermann Lutz, Wacker Polymer Systems GmbH & Co KG, D-84489 Burghausen, Germany 1. Introduction ............... 1 2. Development ............... 2 2.1. Historical and Technical Develop- ment ..................... 2 2.2. Advantages of Dry-Mix Mortars .. 2 3. Composition ............... 4 3.1. Binders ................... 4 3.1.1. Mineral Binders .............. 5 3.1.2. Organic Binders .............. 5 3.2. Aggregates ................ 6 3.3. Additives .................. 6 3.3.1. Cellulose Ethers ............. 7 3.3.2. Other Additives .............. 8 4. Production ................ 10 5. Testing ................... 11 6. Applications ............... 13 6.1. Brick-Laying Mortars and Related Adhesives ................. 13 6.2. Renders and Plasters .......... 13 6.3. Tile Adhesives .............. 16 6.4. Tile Grouts ................ 18 6.5. Exterior Thermal Insulation Com- posite Systems .............. 19 6.6. Powder Paints .............. 21 6.7. Cementitious Waterproofing Seal- ing Slurries ................ 22 6.8. Self-Leveling Underlayments and Screeds ................... 23 6.9. Patching and Repair Mortars .... 24 7. Market Aspects ............. 25 8. References ................. 25 1. Introduction Mortars based on mineral binders like lime, cement, or gypsum have been used for more than 8000 years in the construction of build- ings. These mortars have mainly been used for laying stones and bricks (masonry mortars) and for coating walls (rendering mortars). Until the 1950s cement-based mineral mortars were ex- clusively produced and applied by so-called job- site mixing technology. Job-site mixing means transportation of the individual raw materials to the job-site and their mixing on site in the ap- propriate ratio. Thus cement, the most common mineral binder, is mixed with fillers (sand) be- fore water is added to create the wet mortar for application. Similar to the way in which job-site-mixed concrete was substituted by the economically and ecologically more favorable ready-mix con- crete, job-site mixing techology for masonry and rendering mortars was replaced by factory- mixed dry mortars, also called dry-mix mortars. Dry-mix mortars or dry mortars are produced in specially designed dry-mix mortar plants in which mineral binder(s) and aggregates (sand) are mixed together in the appropriate way. This factory-based process also allows different addi- tives and admixes to be added to these dry mor- tars to improve significantly their technical per- formance. Based on this technology individual dry mortars for specific applications can be pro- duced according to formulations developed and pretested in the laboratory. The factory-mixed dry mortars are delivered to the construction site in bags or in special si- los and need only be mixed with water prior to use. Together with the appropriate equipment for efficient transport, mixing with water, and ma- chine application of the wet mortar, this dry-mix mortar technology led to a drastic improvement in productivity in the application of high-volume products like masonry and rendering mortars. The possibility of adding specific dry addi- tives or admixes in a well defined ratio to the dry mix during the production also led to the de- velopment of high-quality mineral mortars with well-defined and specific technical properties. These highly specialized mortars correspond- ing to the requirements of the modern build- ing industry can not be produced with job-site
Mortars based on mineral binders like lime,cement, or gypsum have been used for morethan 8000 years in the construction of build-ings. These mortars have mainly been used forlaying stones and bricks (masonry mortars) andfor coating walls (rendering mortars). Until the1950s cement-based mineral mortars were ex-clusively produced and applied by so-called job-site mixing technology. Job-site mixing meanstransportation of the individual raw materials tothe job-site and their mixing on site in the ap-propriate ratio. Thus cement, the most commonmineral binder, is mixed with fillers (sand) be-fore water is added to create the wet mortar forapplication.
Similar to the way in which job-site-mixedconcrete was substituted by the economicallyand ecologically more favorable ready-mix con-crete, job-site mixing techology for masonryand rendering mortars was replaced by factory-mixed dry mortars, also called dry-mix mortars.Dry-mix mortars or dry mortars are producedin specially designed dry-mix mortar plants inwhich mineral binder(s) and aggregates (sand)
are mixed together in the appropriate way. Thisfactory-based process also allows different addi-tives and admixes to be added to these dry mor-tars to improve significantly their technical per-formance. Based on this technology individualdry mortars for specific applications can be pro-duced according to formulations developed andpretested in the laboratory.
The factory-mixed dry mortars are deliveredto the construction site in bags or in special si-los and need only be mixed with water prior touse. Togetherwith the appropriate equipment forefficient transport, mixing with water, and ma-chine application of the wet mortar, this dry-mixmortar technology led to a drastic improvementin productivity in the application of high-volumeproducts like masonry and rendering mortars.
The possibility of adding specific dry addi-tives or admixes in a well defined ratio to thedry mix during the production also led to the de-velopment of high-quality mineral mortars withwell-defined and specific technical properties.These highly specialized mortars correspond-ing to the requirements of the modern build-ing industry can not be produced with job-site
2 Dry Mortars
mortar technology. Consequently, high-quality,additive- and admix-modified mineral mortarsare today widely used in the building industryand have largely substituted other buildingmate-rials such as ready-to-use paste compounds andliquid admixes used in combination with min-eral mortars.
2. Development
2.1. Historical and TechnicalDevelopment
For thousands of years the architecture and con-struction of buildings were closely associatedwith the use of mineral mortars. Lime plastershave been known for more than 8000 years, andgypsum mortars were used by the Babyloniansabout 6000 years ago. Hydraulic-setting mor-tars based on pozzolans (powdered volcanic ash)have probably been known for over 3000 yearsand were used in large amounts by the ancientPhoenicians, Greeks, and Romans.
In antiquity and the Middle Ages, additivesand admixes such as soaps, resins, proteins, andash were alreadymixed on the job site with min-eral binders and aggregates to improve the tech-nical performance of the resulting mortars.
Although a first patent on the manufactureand application of dry-mix mortars was pub-lished as early as 1893 in Europe, mortars wereapplied up to the 1950s exclusively as job-site-mixed mortars. For these mortars, the mineralbinders (mostly cement) and aggregates (mostlyquartz sand) are transported separately to the jobsite and are then mixed together by hand in theappropriate ratio. After mixing with water, thewet mortar is ready for application.
During the 1950s and 1960s in Western Eu-rope and in the USA, but especially in Ger-many, there was a fast-growing demand in theconstruction industry for new building materi-als and technologies. The reasons for this in-cluded shortage of skilled workmen, the needfor shorter construction times together with costreduction, increasing labor costs, the diversifi-cation of building materials suitable for specificapplications, newmaterials, and an increased de-mand for better quality of construction.
Job-site mortar technology was and is notable to adequately meet all these requirements.
As a practical consequence the development ofthe modern construction and building chemicalindustry in the countries of the Western worldfrom the 1960s onwards was influenced mainlyby three important trends, which can be seennowadays worldwide:
– Replacement of the job-site-mixed mortarsbypremixed andprepackeddry-mixmortars.
– Mechanizationofmortar application, includ-ing bulk transportation systems (e.g., silos),mechanical systems for automatic mixing ofdry-mix mortar with water, and machine ap-plication (spraying) of wet mortar.
– Modification of mortars with polymerbinders (redispersible powders) and specialadditives (e.g., cellulose ethers) and admixesto improve product quality and to meet therequirements of the modern building indus-try.
The introduction of dry-mix mortar techol-ogy and the use of silo transport and machineappliation of mortars made it possible that from1960 to 1995 the volume of render and plas-ter mortar application in Germany increased by600 %, while the number of employees in thissector decreased by 25 %, that means, produc-tivity increased by 800 % [1].
2.2. Advantages of Dry-Mix Mortars
In job-site mixing technology, for each buildingapplication a specific ratio of cement and fillersis mixed appropriately before being gaugedwithwater, and the wet mortar is applied. The qualityof such a mortar depends on the quality of theraw materials, their correct mixing ratio, the ho-mogeneity of the mixture, and the consistencyof the fresh mortar. Under these conditions thequality ofmortars producedby job-sitemix tech-nology can not be guaranteed. The main disad-vantages of job-site-mixed mortars are that thewhole process cannot be automated, and the pro-ducer and applicator of a job-site-mixed mortarcan not give a warranty to customers and endusers due to a high risk of inconsistent quality ofthe prepared mortars. In addition, additives caneither not be added or can only be added witha high risk of dosage and mixing errors and ofobtaining inhomogeneous mixtures. The possi-bilities for producing specialized and individual
Dry Mortars 3
products with job-site technology are very lim-ited. Last but not least, handling and the logisticsof job-site-mixedmortars aremore complicated,and their applications are very limited.
In contrast to construction-site mortars, themodern dry-mix mortars are produced in a dry-mix mortar plant by mixing together all neces-sary ingredients such as binders, aggregates, andchemical additives. In this way different kinds ofdry-mixmortarswithwell-defined product char-acteristics that correspond to the requirementsfor specific applications can be produced. Theuse of premixed and prepacked dry-mix mor-tars not only increases significantly productionperformance and the productivity on construc-tion sites, but also guarantees a high degree ofapplication safety and reliability in avoiding on-site mixing errors. Prepacked dry-mix mortarsproduced in a dry-mix plant assure that binders,aggregates, and additives of high and constantquality are mixed exactly in the same ratio, thusensuring a consistent high level of quality [2],[3].
The raw materials used for the production ofprepacked dry-mix mortars can be classified asfollows:
1) Mineral bindersa) Portland cement (OPC)b) High-alumina cement (HAC)c) Special cementsd) Hydrated limee) Gypsumf) Anhydrite
The two different approaches to producefresh, wet mortars ready for application eitheras a job-site mixed mortar (processA) or as afactory-made prepacked dry-mix mortar (pro-cess B) have major consequences for handlingand productivity, as exemplified for base-renderapplication in Table 1.
The application of high-volume dry-mixmortar was strongly promoted by the develop-ment of bulk transportation containers (silo sys-tems) and mechanical systems for gauging themortars with water and pumping for mechanicalapplication by spraying. Compared to the man-ual gauging of dry-mixmortars delivered in bagsto the job site (process B), the use of automaticgauging and pumping devices for the mechan-ical application of the mortar leads to an addi-tional improvement in productivity (processD).
4 Dry Mortars
Table 1. Comparison of production, transport, and application of job-site-mixed mortars and dry-mix mortars
Process∗ A B C DTransport of sand and cement separately to the job-site +Manual mixing of the mineral binder and the aggregates on the job site +Transport of the prepacked dry-mix mortar in bags to the job site + +Transport of the prepacked dry-mix mortar in silos to the job site +Manual mixing of the mortar with water + +Manual application of the wet mortar + +Machine mixing of the dry-mix mortar with water and machine spray application + +Productivity (m2 per man shift) for a render application 10 25 40 50 – 60
∗A: completely manual method (job-site mixing technique); B, C, D: dry-mix mortar production in a dry-mix plant with differentmethods of transport and application.
The handling of dry-mix mortars in bagscould be eliminated for many high-consumptionapplications by filling the dry-mix mortars pro-duced in the dry-mix plant into containers1 – 20m3 in volumewhich are transported to thesite.With appropriate conveying systems the drymortar is transferred directly from the silo intothe attached mixing and pumping unit, where itis gauged automatically with water and pumpedfor spraying.
Combining the transportation of the dry-mixmortar in silos or containers with automaticgauging, pumping, and mechanical applicationof the mortar provides a further improvementin productivity (processD). In addition to theimproved productivity, the automatic mechan-ical gauging and spraying of dry-mix mortarsensures consistency in handling and applicationof these products. Possible errors such as over-or underdosage of water or incorrect composi-tion of themortars are eliminated, which is espe-cially important if less experienced or unskilledworkers are working on the job site.
In Western Europe the consequences of thisdevelopment were phenomenal. Since the 1960sa huge number ofmodern drymortar plants havebeen established with millions of tonnes of ca-pacity. In Germany, for example, nowadays ap-proximately 100 drymortar plants exist, produc-ing 10× 106 t/a of dry-mix mortars. There wasa tremendous boom in dry-mix mortar technol-ogy after reunification of Germany after 1990,which now continues in the countries of East-ern Europe. The average growth rate for dry-mixmortar applications in Europe is approximately12% per annum, based on a production of about35 – 40× 106 t/a in 2000 [4].
3. Composition
Dry mortars are generally composed at least ofthree components: a binder, an aggregate, andadditives.
Modern dry mortars are composed of manymore components than those which were mixeddirectly on the site in the past. Today the simplestformulations are masonry mortars, brick-layingmortars, and low-quality tile adhesives, whilehighly sophisticated and high-performance drymortars like self-leveling floor underlaymentsand decorative plasters may contain up to 20 in-gredients. In this article the word aggregates isused for all types of mineral ingredients whichdo not have a binder function, even if they areadded in small amounts like mineral ingredientswith special functions, e.g., functional fibers orpigments. Other ingredients with small additionrates (redispersible powders) are treated as or-ganic binders, although many others describethem as additives. The effect of using redis-persible powders, especially in tile adhesives,shows clearly that they have a binder function.On the other hand, methyl cellulose, a multi-purpose additive, is described in the chapter onadditives although it also has a certain binder ef-fect. In this case the binder effect does not playthe major role.
3.1. Binders
The binder glues aggregates and other parti-cles together and provides adhesion to the sub-strate. Due to their physical or chemical reactionbinders play the major role for the final strengthof the mortar. Binders can be classified as hy-draulic and nonhydraulic binders. The formeralso set under water.
Dry Mortars 5
The setting reaction of the binders cementand hydrate lime occurs by chemical reaction.Cement reacts on contact withwater duringmix-ing while hydrate lime (without hydraulic por-tions) sets by reaction with atmospheric carbondioxide. Gypsum and organic binders set phys-ically: gypsum by recrystallization with waterand formation of matted crystal needles, and or-ganic binders by forming a homogeneous poly-mer film.
3.1.1. Mineral Binders
Cement (see also →Cement and Concrete).In dry mortars ordinary portland cement (OPC)is mainly used. The hydration reaction leads pri-marily to the formation of calcium silicate hy-drates, which retain their strength and stabilityeven under water (hydraulic binder). While thequality of anOPC likeCEM I 32.5R (for nomen-clature, see DIN 1164 [5]) is sufficient for brick-laying mortars, masonry cement, renders, andmany plasters, in tile adhesives higher qualitieslike CEM I 42.5R or CEM I 52.5R are desired.Dry mortars that are both mortars and decora-tive finishes, such as decorative plasters and tilegrouts, mostly contain white portland cement.Fast-setting high-alumina cement (e.g., FondueLafarge) consists mainly of calcium aluminatesand is used for dry mortars that require fast-setting properties or high-temperature stability.
Gypsum [6] (see also →Calcium Sulfate).Calcium sulfate hemihydrate and anhydrite bothset with water by forming calcium sulfate dihy-drate.
Calcium sulfate hemihydrate exists in twocrystalline forms (depending on the productionprocess): the α-form with larger crystals, highertensile and compressive strength, and lower wa-ter demand, and the more amorphous β-formwith high porosity and lower tensile and com-pressive strength and an up to three times higherwater demand.
Anhydrite exists in two application-relevantphases: the anhydrite II phase, which is of im-portance in anhydrite-based screeds and the an-hydrite III phase, which is a part of the multi-phase gypsum used for plasters. Gypsum plas-ters contain β-hemihydrate as well as anhy-
drite II and III. Gypsum-based joint filler con-tains β-semihydrate.
Hydrated Lime (see also →Lime andLimestone), [7]. Hydrated lime sets by reactionwith carbon dioxide to form calcium carbonateand is therefore not a hydraulic binder. Hy-draulic properties in some hydrated lime resultfrom impurities or added materials with poz-zolanic properties. For centuries hydrated limewas by far the most important binder in mor-tars. Today it is largely substituted by hydraulicbinders, which set faster, but it is still in use,mainly because of its plastic properties. Theworkability of many dry mortars is improved byadding 5 – 30wt % hydrated lime to the cement.Limes (including powdered hydrated lime) forbuilding purposes are specified in DIN EN 459[8].
3.1.2. Organic Binders
Improving the characteristics of a cementitiousmortar with organic materials is well known. Inantiquity, for example, proteins in the form ofliquid milk or even blood were used. In mostmodern applications, mortars unmodified by or-ganic polymer binders are no longer able tomeetstate-of-the art technical requirements. Even ce-mentitious mortars that contain cellulose ethersas an additive to improve their water-retentioncapability and workability characteristics ad-here poorly, or not at all, to many of the ma-terials used in the modern construction indus-try (e.g., polystyrene, cement fiber and woodpanel; non-absorbent substrates like old tiles andfully vitrified tiles). Furthermore, cementitiousmortars are very hard, brittle, and inflexible ma-terials, but for many applications flexible anddeformable cementitious mortars must be used.Thus, for many applications in the modern con-struction industry the modification of cementi-tious mortars with polymers today is a must. Intwo-binder systems, the mineral binder cementand the polymer binder in the form of a redis-persible powder complement each other ideally.Their combination results in outstanding syner-gistic properties and characteristics of the dry-mix mortar which cannot be produced by eitherof the two individual binders alone.
6 Dry Mortars
In the early 1930s water-based liquid disper-sions [9] were added prior to or together withthe gauging water if required.Mortars which aremodified in this way are referred to as two-packsystems (powder-form mineral binder plus liq-uid polymer binder in a second pack). However,in practice many faults occurred with the useof the two-pack (or two-component) systems atthe construction site. The main difficulty is theprecise dosing of the polymer dispersion in itsliquid form.
Dosing errors may occur due to insufficientknowledge, experience, and training of work-ers concerning the appropriate dosage for a spe-cific application with precise requirements, ordue to incorrect dosage, which may happen un-intentionally by error or even intentionally tosave on short-term costs. Incorrect dosage ofthe liquid polymer dispersion will change thecharacteristics and the technical performance ofthe mortar significantly, and this will lead to se-vere damages in various construction materials,e.g., through insufficient adhesive bond strength,flexibility and/or durability. Other reasons thatargue against two-pack systems, apart from thedifficult and risky handling, are the additionalexpenses and logistics difficulties (e.g., the needfor additional containers and their subsequentdisposal, storage and transport of liquid disper-sions which could freeze or deteriorate by mi-crobiological attack, more time consuming andponderous handling on the job site with the two-pack system).
gether the filler particles, reinforcing the mortarstructure and providing an excellent adhesion atthemortar – substrate interface. Polymer films ina cement mortar are shown in Figure 1.
The use of factory-made dry-mix mortarswith precisely stipulated proportions for cement,aggregates, additives, and redispersible powdersas organic binder results in a high-quality prod-uct with a high degree of application safety byavoiding possible errors during dosing and mix-ing at the construction site.
The modification of dry-mix mortars with re-dispersible polymer powders improves, depend-ing on the dosage, the adhesive bond strengthon all kind of substrates, the flexibility and de-formability of the mortars, the flexural strength,and the abrasion resistance, the toughness, thecohesion and the density (impermeability) of themortar as well as the water retentivity and theworkability characteristics. In addition specialredispersible powders with a hydrophobing ef-fect can result in a strong water-repellent effectof the mortars.
3.2. Aggregates
The majority of aggregates are normal size frac-tions of quartz, limestone, or dolomite. To ad-just the grain-size distribution (see Section 5)normally different granulometric fractions ofaggregates are necessary. Additionally decora-tive fractions of special granulometries like cal-cite, marble, jurassic limestone, or mica areused, mainly for decorative plasters. To re-duce the density of a dry mortar and to in-crease the insulation effect lightweight aggre-gates like perlite, vermiculite, glass foam, ex-panded clay, and pumice are used as additionalaggregates. Because of their low density (typ-ically 80 – 500 kg/m3) only few per cent byweight is added to the mix. Dry mortars for dec-orative renders or tile grouts are often coloredwith pigments.
3.3. Additives
Without additivesmodern drymortarswould notexist and many technical properties could not beachieved. Relative to the mineral ingredients thecontent of additives typically lies between 0.1
Dry Mortars 7
Figure 1. Scanning electron micrograph (× 1500; Wacker Polymer Systems) of the interface between a polymer-modifiedceramic-tile adhesive (left) on a porcelain tile (right). The polymer films at the interface between the surface of the porcelaintile and the cementitious mortar can be seen clearly.
and 10wt %. The additives are of organic or in-organic origin, often of polymeric nature. Theycan improve the mixing of the dry mortar withwater, the properties of the wet mortar such asrheological behavior or the workability as wellas the properties of the set mortar including thesetting behavior.
3.3.1. Cellulose Ethers [12]
Cellulose ethers are used as thickening and wa-ter retaining agents in dry mortars. Celluloseethers are of major importance as additives,even though their addition rate is very low (nor-mally 0.02 – 0.7 %). Out of all additives cellu-lose ethers together with redispersible powderscause the largest range of effects in dry mortars.The mainly used cellulose ethers in dry mor-tars are methyl hydroxyethyl cellulose (MHEC)and methyl hydroxypropyl cellulose (MHPC).Together they have a market share in dry mor-tars of at least 90 %. Colloquially they are stillcalled “methyl cellulose” or “MC”, althoughpure methyl cellulose today has a very smallmarket share. Other technically relevant cellu-lose ethers with a small share in the dry-mortarmarket are ethyl hydroxyethyl cellulose (EHEC)and hydroxyethyl cellulose (HEC). As (sodium)carboxymethyl cellulose is not stable in the pres-
ence of calcium ions, it is used only in few ap-plications as a thickener.
The following sections cover relevant prop-erties of MHEC andMHPC. As these propertiesare valid for both products, here they are simplyreferred to as MC.
Formation of Solutions and Wet MortarMixes;ViscosityBuildup. MC iswater-solubleon a large temperature range. The most suit-able MC’s for dry mixes are powders whereby20 – 60wt % of the particles have a size smallerthan 63µm. The dry mix, in which MC parti-cles are dispersed between binder and aggre-gate particles, avoids the formation of lumpswhich occurs only if powders are poured di-rectly into water. CoarseMC products, normallyclassified as granular materials, are easy to dis-solve in water without lump formation, but theirslowdissolutionmakes themunfavorable for drymortar mixes. For dry mortars with a neutralpH it should be considered that the granulom-etry is not the only parameter deciding the so-lution behavior of the MC. Some MC-gradesare covered with a chemical crosslinking agent(“retarded solubility”), which causes particles todissolve quickly only under alkaline conditions(e.g., coming from cement or hydrated lime).The alkalinity leads to an immediate breakdownof the crosslinking as well as to a fast dissolution
8 Dry Mortars
of the MC in the mortar. Originally MC gradeswith retarded solubility were not developed fordrymortar, however, theyhave eventuelly spreadto the dry mortar market.
In pure solution and in a wet mortar, MCbuilds up a certain viscosity. The differencesbetween low and high viscosities can be seeneasily in a 2 % aqueous solution. Many MCsare specified by their viscosity measured at thisconcentration. The viscosities of such solutionsvaries between aqueous (viscosity up to a fewhundred millipascals) up to jellylike (viscosityof several thousand millipascals). Different MCproducers use different methods and apparatusto specify the viscosity of their MCs: the HaakeRotovisko, Hoppler, Ubbelohde, and Brookfieldmethods aremainly in use. The results of viscos-ity measurements on the same sample can dif-fer by up to several hundred per cent betweentwo methods, and this should be borne in mindwhen comparing viscosities ofMCs from differ-ent producers.
Stickiness and Workability. Stickiness isan expression mainly used in the leveling ofplasters and renders. Here “stickiness” meansthe feeling of adhesion that the worker expe-riences to be between the leveling tool and thewall. High stickiness requires more force duringleveling and results in a lower workability. Bothproperties can be influenced by the MC.
Water Retention. The water retention value(WRV) of a mineral plaster is the percentageof water that remains in the plaster after capil-lary dewatering by an absorbant substrate (DIN18555, part 7) [13].
Cement- and gypsum-based mortars needwater for setting, and this water must be retainedin the mortar for a longer period of time. Thethickness of thick-bedmortarswidely used in thepast (normally in the range of centimeters) pro-tected the mortars from drying out too fast aftercoming into contact with water absorbing sub-strates, the sun, or other environmental condi-tions likewind, dry air, or a high ambient temper-ature. Today, wall materials with high capillaryforces are used (e.g., aveated light weight con-crete), and the thickness of mortar layers gener-ally has decreased. MC is necessary to retain thewater during the setting reaction. The highwaterretention of a modern dry mortar is mainly due
to MC. Figures 2 and 3 show an example of thewater retention of a wet mortar as a function ofconcentration and viscosity, respectively, of theadded MC.
For the measurement of water retention seeSection 5.
Water Demand and Yield. A mortar re-quires a certain consistencywhich is well knownto skilled workers. They add as much water asis necessary to get the right consistency. Thewater demand depends on the ingredients andtheir addition rate in the formulation. MC isthe main factor which influences the water de-mand. Mainly the viscosity, the addition rate,and the additional thickening effect of MC arethe parameters. The water demand (water-solid-factor) influences also the yield of a mortar. Itis measured in liters of wet mortar per 100 kgof dry mortar and is an important parameter forthe efficiency of lightweight plasters. Some MCproducers supply special MCs which garanteeshigh yields in themortar. This can help to reducethe amount of lightweight aggregates.
Other properties which can be influencedwith MCs are open time and tensile adhesionstrength of a tile adhesive as well as the slip re-sistance of a tile in the mortar (see Section 5),the rheological properties, plastification, and lu-brication.
3.3.2. Other Additives
Starch Ethers. Mainly hydroxypropylstarches are added to plasters. Despite theirlow viscosities (mainly 100 – 500mPa s in 2 %solution) they distinctly increase the viscosityof mortars when added to MC-containing mor-tars. Typical addition rates are between 0.01 and0.04 % in cement-based renders and plasters,and 0.02 – 0.06 % in gypsum-based plasters.The water demand of the plaster is slightly in-creased, and this is associated with a slightlyhigher yield. The water retention of the mortaris not increased. With regard to the workabilitythe sagging of the wet mortar from vertical wallsand supports is reduced. At the optimum dosagethe workabilities are improved.
Air-entraining agents act physically by en-training air micropores in the mortar. This leads
Dry Mortars 9
Figure 2. Water retention of a wet mortar as a function of the concentration of the added methyl cellulose (Walocel MKX30 000 PP 01,Wolff Cellulosics, viscosity 30 000mPa s, measured with a Haake Rotovisko)
Figure 3.Water retention of a wet mortar as a function of the viscosity of methyl cellulose (2 % solution, 20 ◦C, shear rate:D = 2.5 s−1, measured with a Haake Rotovisko)
to a decreased wet mortar density, a better work-ability, and a higher wet mortar yield. Theincluded air leads to better insulation againstcold and heat, but also to lower strength. Air-entraining agents are based on powder formand mainly sodium salts of fatty acid sulfonatesand sulfates. The addition rates in plasters andmasonry mortars normally varies from 0.01 to0.06%.Theoptimumaddition rates canbe foundby monitoring the air content of the mortar andits workability.
Hydrophobic agents (water-repellentagents) prevent water from penetrating intothe mortar, but the mortar remains still openfor water vapor diffusion. The performance ofhydrophobic agents can be measured by thecapillary water absorption (DIN 52617) [14].
Superplasticisers have a strong influence onthe water demand of a mortar. A mortar con-taining superplasticisers requires less water thanusual to get the same consitency. Consequently,an unchanged water demand leads to a lower-ing of the consistency. The effect of superplas-tification is explained by the model [15] thatdifferent surface charges of the cement parti-cles lead to the inclusion of water when theyagglomerate. By the adsorption of the super-plasticiser the surfaces are discharged and wa-ter is set free. Depending on legal restrictionsand technical advantages casein (many produc-ers) or synthetic superplasticizers are used, e.g.,on the basis of sulfonates of lignin, naphtha-lene, melamine – formaldehyde condensates, orpolyether carboxylates. Examples of producersare SKW (Trostberg, Germany), Sika (Switzer-land), and Perstorp (Sweden). Superplastizisersaremainly used inmortarswhich need very goodself-leveling properties like self-leveling floorunderlayments, screeds, and pourable flooringtile adhesives. The dosage normally lies in therange of 0.2 – 1 %.
Fibers can be distinguished into two groups:long fibers are mainly used for reinforcementof mortars. Short fibers (e.g., Arbocel and Lig-nocel grades from J. Rettenmaier & Sohne,Ellwangen-Holzmuhle, Germany) are used in
influence wet-mortar properties and water de-mand.
Defoamers reduce the air content inwetmor-tars (e.g., Agitan P products from MunzingChemie, Heilbronn, Germany). Powder de-foamers on a different chemical basis (mainlyhydrocarbons, polyglycols or polysiloxanes onan inorganic carrier) are in use.
4. Production
Production, storage, transport, and quality con-trol of dry-mixmortars are defined inDIN18557[16].
Modern dry-mix plants (Fig. 4) with aproduction capacity of typically 40 000 to250 000 t/a mostly are built on a small area be-cause the production line is oriented vertically,and the silos for the raw materials are placedabove the mixing unit.
After appropriate quality control, the rawma-terials are transported by the receiving system tothe different silos at the top of the plant. Con-sequently, the material flow is mainly gravita-tional, which saves on investment and runningcosts. The rawmaterials are transferred by grav-ity or by appropriate conveying systems (diskfeeders, dosing screws, pneumatically) into thehigh-accuracy hopper-scales weighing system.Controlled by the fully automated electroniccontrol system, the mixing unit is filled withall raw materials needed for each formulationfor a specific dry-mix mortar. As mixing unitmostly special mixers are used which are suit-able for thewhole product range of dry-mixmor-tars (from fine-particle materials up to coarsedry mortars). Such mixing units, available in awide variety of different sizes and designs, allowshort batch cycle times and fast, homogeneousmixing. The temperature of the dry-mix mate-rials should not exceed 50 ◦C during the wholemixing process to avoid deteriorating the ther-moplastic and sensitive additives. After a shortmixing process of about 3 – 10min for highly ef-ficient modern mixing units, the homogeneousdry-mix mortar is discharged into the interme-diate finished-product storage silo. After qualitycontrol, the dry-mix mortar is discharged intotransport silos or transferred to bagging and pal-letizing units, ready for the transport to the con-
Dry Mortars 11
Figure 4. Schematic diagram of a dry-mix mortar plant (m-tec, Neuenburg, Germany)
struction site. Figure 5 shows a typical dry-mixmortar plant.
In the production of dry-mix mortars, thequality of all raw materials used, especially thebulk mineral materials, must be controlled ac-cording to the national standards (e.g., EN 196for cements). If aggregates like silica quartzsands are not available in the appropriate quality,the dry-mix mortar plant must include installa-tions for grinding, washing, drying, and classifi-cation into different sieve fractions. The residualhumidity of all fillers should not be higher than0.3 %, and the temperature of the sand after thedrying process should not exceed 60 ◦C beforebeing used. The sieve curve within the differentfiller fractions should be constant without largevariations (e.g., by combining several subfrac-tions).
The design, the size and the number of si-los for all raw materials and the design of thewholemixing and packaging unit depends on the
raw materials available and the number, types,and volume of different dry-mix mortars to beproduced in the dry-mix mortar plant. For allgypsum-based products usually a separate pro-duction line is used to avoid contact or mixingof cement-based products with gypsum.
5. Testing
Consistency. Applying a mortar to a supportrequires to mix it with a certain amount of wa-ter. Skilled building workers instinctively mixthe dry mortar with the amount of water whichleads to the desired application consistency. Ahigher or lower amount of water leads to unde-sired properties. The required amount of waterfor mixing is described by the term w/s (waterto solid ratio).
During the development of a dry mortar thew/s values should be adjusted to a consistencywhich will probably be used also on build-ing sites. If formulations with different addi-tion rates of additives or different additives arecompared, it is generally worthless to compareformulations with the same w/s, because nearlyall additives change the consistency or the w/sslightly. To find a way of controlling the con-sistency and to compare different formulations,several testing procedures exist. The consistencyof mortars, renders, and plasters is checked bythe slumpmethod,which is done in a similarwayas in the concrete industry (→Cement and Con-crete, Chap. 2.4.1.). The standards DIN 1168,part 2 (only for gypsum-based products) [17],DIN EN 13279, part 2 [18], and DIN 18555,part 2 (for mortars with mineral binders) [13],define the slump to be “the diameter in millime-ters of a patmadeof amixture ofwater andbuild-ing plaster and formed by vertical blows afterremoval from the mold and jolting of the mix-ture” [13]. The consistency of more liquid prod-
ucts like self-leveling floor screeds or pourableflooring tile adhesive can be determined by thediameter of flow. This procedure does not re-quire jolting. The consistency of a tile adhesivecan be controlled by viscosity.
Water Retention. The standard DIN 18555,part 7 [13] describes the measurement of wa-ter retention. The water-absorbing wall is sim-ulated by water-absorbing filter plates. The testis carried out on a plaster with a consistencyas used in practice. The wet mortar is spreadonto filter plates. After a certain time the wateramount absorbed by the filter plates is weighed.Than the water retention is calculated in %. Dif-ferent kinds of mortars require different water-retention values for good application properties.
Setting Time. The setting behavior ofgypsum-based building plasters is determinedby the Vicat needle test according to DIN EN13279, part 2 and DIN 1168, part 2. [17], [18]:“The start of setting of building plasters contain-ing additives is indicated by the time in minutesafter which a Vicat needle, in the course of apenetration test into a plaster sample, comes toa standstill at a specified height.” The time iscalculated from the commencement of moisten-ing of the building plaster with water. Coarsersystems such as cement renders and plasters areless suitable for the Vicat testing procedure.
Air content. Freshly mixed mortars containpores, one origin of them being air entrainingagents, another being adsorbed air on the surfaceof the particles. DIN 18555 part 2 [13] describesa method to determine the total amount of airpores in a fresh mortar. It is an integral methodwhich does not give any indication about the sizeor the distribution of the pores. “The air contentof freshmortar shall bemeasured by the pressuremethod using a preset test apparatus with a ca-pacity of 1 dm3. The test apparatus shall have apressure chamber in which a defined pressure isproduced. By opening an overflow valve a pres-sure balance is affected between the pressurechamber and the sample container (measuringvessel) which is filled with fresh mortar. Thedrop in pressure is a measure of the air contentin the fresh mortar.” [13]
Dry Mortars 13
Granulometric analysis mainly is donewith screen sizing. The residues on the testsieves are weighed and expressed as a percent-age of the initial weight. Plotting the diameterof the particles as a function of the percentagesieve passage gives the individual granulometriccurve. The curve has a specific shape for eachdry mortar. The coursness of dry mortars alsovaries (Fig. 6). The granulometric range of mostdry mortars varies between 0.1 and 4mm.
In some mortars a high wet mortar density isnecessary to lead to high compressive strengths.In such cases the granulometric distribution ofall mineral components should be optimized ac-cordingly. To use a simple picture, the spacesbetween the bigger particles should be filled bysmaller particles to give the best space filling.This best distribution of diameters of particlescan be calculated and and plotted as a Fullercurve (Fig. 7).
Open Time. In the colloquial speech used onthe building sites “open time” is a general ex-pression for the length of time in which a freshlymixed mortar can be applied. The expression“open time” mainly is used for applying tile ad-hesives, sometimes also for plastering and ren-dering. Amore precise definition of “open time”is given in the following three definitions: Theformer DIN 18156 (part 2) defines the “opentime” to be the time between the application ofthe mortar layer and the formation of a skin. Theskin formation can only be tested qualitativelywith a wad of cotton. Another testing proceduredefines the “open time” as the time after whichthe wetting of the back of the tile is at least 50 %of the square of the tile. Nowadays Europeanlaboratories are testing the open time mainly ac-cording to EN1346 [19]. Here the open time (inminutes) is the largest time range after whichthe necessary tensile strength of a tile adhesiveaccording to EN 12004 is reached. The testedtimes are 5, 10, 20, and 30min.
Slip Resistance. A tile adhesive should havea good slip resistance mainly for the followingtwo reasons: for tiling with heavy tiles like mar-ble tiles, and second for countries where thetiling of a wall starts from the top (as in Ger-many) and not at the bottom. In the latter casethe lower tile supports the upper tile and preventsit from slipping down.
The slip resistance is measured with a stan-dard tile of size 10× 10 cmand aweight of 200 gon a concrete slab according to EN 1308 [20].
Tensile adhesion strength is an importantproperty of many dry mortars. For tile adhesivesEN 1348 [21] specifies four conditions of stor-age: standard storage under standard climaticconditions for 28 d, after water immersion, afterfreeze – thaw cycle, and after heat aging storage.
6. Applications
6.1. Brick-Laying Mortars and RelatedAdhesives
Brick-laying mortars are used to join all kindsof bricks: red clay bricks with lowwater absorp-tion, strongly absorbing sand-lime bricks, andaerated light weight concrete. Generally, brickswith low water retention applied in thick layersrequire mortars with low water retention, whilesmooth and even bricks with high water absorp-tion require a mortar with high water retentionapplied in thin layers. Table 2 lists the differentformulations.
DIN18555, parts 1 – 9 [13] describes the test-ing of mortars with mineral binders. Most ofthem are valid for brick-layingmortars aswell asfor cement-based renders and gypsum plasters.
Table 2.Typical formulations of a brick-layingmortar and an aeratedlight weight concrete adhesive (in parts by weight)
Component Brick-layingmortar
Aerated lightweight concreteadhesive
Cement (e.g., CEM I 32.5R) 12 – 20 36Hydrated lime 0 – 6 4Limestone dust, 0 – 0.1mm 10 – 20Quartz or limestone sand,0 – 4mm
Plaster is defined inDIN18550, part 1 as “a coat-ing of plastermortar or coatingmaterials appliedto walls and ceilings in one or more layers in a
14 Dry Mortars
Figure 6.Maximum grain size of some European mortars (mm)
Figure 7. Reference curves calculated from the Fuller equation
specified thickness,which does not acquire its fi-nal characteristics until it has set on the buildingcomponent” [22]. Different types of dry mortarrender and plaster are classified on the basis ofthe type of binder used:
– Plaster and render mortar with mineralbinders (cement, gypsum, and possibly hy-drated lime)
– Decorative plaster mortar with cement, re-dispersible powder, and possibly hydratedlime as the binder (see Section 5)
Dry mortar render and plaster with otherbinders like potassium silicate, redispersiblepowder as the sole binder, hydrated lime as thesole binder, and clay are not covered here. Plas-ters assume a range of physical tasks, for in-stance, protection against weathering or chemi-cal ormechanical actions.Weatheringmeans the
ingress of moisture or fluctuations in tempera-ture. In addition plasters have to confer adequateprotection against driving rain, but they are usedalso for bathrooms and other roomswheremois-ture occurs. Cement or lime – cement plastersare used to satisfy these requirements.
Render and plaster must have good watervapor permeability and be suitable for paint-ing and hanging heavy papers. Mineral renders,typically applied in a single layer with a thick-ness of ca. 10 – 30mm, also serve as a uniformand smooth substrate or load-bearing layer forsubsequent finishing coating materials like ce-ramic tiles, paints, and decorative finishing coat-ings. Cement-based renders are used for exteriorapplications and wet rooms, whereas gypsum-based renders are used exclusively for interiorwalls.
Dry Mortars 15
Nowadays, in most European countries (notin the UK) machine-applied render/plaster ismuch more common than manually applied ren-der or plaster. Accordingly, the render/plasterfor machine application must fulfill the addi-tional requirements of a very rapid developmentof consistency andhighwater retention.Both pa-rameters are steered by choosing the appropriategrade of methyl cellulose. Next to the trend tomachine application, there is a tendency to usemore lightweight plasters.
Cement and Lime –Cement Renders. Themain requirements for cement and lime – cementrenders are high non-sag properties during ap-plication, easy workability, low stickiness to theleveling tool, and crack-free setting. To fullfillthese requirements, the formulation requires theoptimum concerning granulometry and the ad-dition of additives like methyl cellulose, starchethers, and air-entraining agents. Table 3 liststypical formulations of a lime cement render andof a lightweight render based on cement.
Table 3. Typical formulations of a standard lime – cement renderand a lightweight cement render (in parts by weight)
Lightweight renders for thermal insulationare specified in DIN 18550, parts 3 and 4 [22].
Gypsum Plasters (→Calcium Sulfate). Astheworking steps necessary for a gypsumplasterare more complicated and time-consuming thanfor a cement render, the typical formulations arealsomore complicated.Themain focus is alwayson the correct adjustment of the setting retarda-tion, which enables the worker to finish all stepsof the work before the surface sets or becomesdry. As the working traditions are different inmany countries, the local formulations always
have to be adjusted to the different working pro-cedures. A main difference in working concernsthe final working steps after the second leveling.In central Europe the surface is wetted with wa-ter and a cream is rubbed out of the surface witha sponge, followed by the smoothening with aknife, which results in extremely smooth sur-faces. In southern Europe and Great Britain, wa-tering of the surface is avoided, and this leads toa coarser surface. To obtain the desired smooth-ness, the surface is plastered with a fine-grainedtop coat.
Lightweight gypsum plasters containing per-lite or vermiculite are very common. Especiallyin these formulations methyl cellulose plays animportant role in increasing the yield and sav-ing on the cost of the lightweight aggregates. Ina lightweight gypsum plaster for machine appli-cation the rightMC allows 100 – 200 L of perliteto be saved per tonne of plaster for the same cov-erage compared to a MC without any additionalthickening effect. Such an MC will yield to anapproximately 10%higher coverage of the plas-ter mortar.
The true yield of a machine-appliedlightweight plaster can be measured only in aplaster spaying trial. Typical German gypsumplasters have yields in the range of 80 L/100 kgof dry mortar for a gypsum– lime plaster, andup to 120 L/ 100 kg of dry mortar for machine-applied gypsum lightweight plaster.
Relevant standards are draft DIN EN 13279,parts 1 and 2 [18] (formerly DIN 1168, parts 1and 2).
Table 4 shows typical formulations of a gyp-sum plaster, a gypsum– lime plaster, and alightweight gypsum plaster.
TexturedMineral Finishing Plasters. Min-eral finishing plasters, stuccos, putties, and skimcoats are part of a coating system and are ap-plied usually on a thick-layer base coat (render)or on other types of uniform and smooth sur-faces (concrete, plasterboard, etc.). For exteriorwalls, mainly lime – cement plasters are used asa decorative finishing material. Finishing plas-ters must provide the facade with an opticallyattractive surface finish and have to fulfill phys-ical functions such as a durable protection ofthe covered wall areas and undercoats againstdampness and weathering.
16 Dry Mortars
Table 4. Typical formulations of a gypsum plaster, a gypsum– lime plaster, and a lightweight gypsum plaster (in parts per weight)
To meet their required physical functionsover long periods, mineral finishing coating ma-terials for exterior application must have a goodadhesion to the substrate, a lowwater absorptionand a highwater-repellent effect (low coefficientof water-absorption), good drying characteris-tics (good water-vapor permeability), and lowsusceptibility to cracking; the modulus of elas-ticity of themineral coating should be lower thanthe modulus of elasticity of the layers below it.
These requirements are met in an exem-plarymanner bymineral-textured finishing plas-ters produced as factory made dry-mix mortars.The term “finishing plaster” nowadays refers tofacade-coating materials pigmented in white orlight pastel colorswhich are used as the final sur-face finish without any additional painting beingnecessary. Mineral finishing plasters are com-posed of hydrated lime and cement as mineralbinders, aggregates (fillers), pigments, and ad-ditives such as cellulose ethers and starch ethersto improve the water retention and processing. Ifrequired, other additives such as air entrainers,water-repellent agents, retarders, and fibers areadded. The ratio of cement and hydrated limecan be varied according to the different require-ments; the higher the cement content the higherthe compressive strength, the toughness, and thewater resistance, but there is also a higher riskof crack formation due to the brittleness andshrinkage of the mortar. The higher the contentof hydrated lime, the better the workability, andthe lower the compressive strength. Carbonatefillers such as marble or limestone can be usedadditionally or even exclusively instead of silicasands. The technical performance of the finish-ing plaster can be improved significantly by theaddition of organic polymer binders in the form
of redispersible powders. The different struc-tures of the hardened mortar originate from adifferent particle size distribution of the fillersused in the formulation (structure-giving largegrains) and from the application method (appli-cation by spraying, brush, trowel, roller, etc.).Mineral finishing plaster is appliedmanually butnowadays increasingly by machine spraying.
The standard DIN 18550 [22] defines thetechnical requirements and the application ofmineral base renders as well as of the finishingplaster coating systems.
6.3. Tile Adhesives
Ceramic wall cladding for building interiors andexteriors is by no mean a new invention. Thefirst ceramic wall cladding materials in form offresco and mosaic tiles were produced ca. 3500years ago in Egypt, Persia, and China. Tiles pro-vide an esthetically attractive decorative surfacein combination with important functional ben-efits, being water resistant, tough, long-lasting,hygienic, and easy to clean. For these reasonstiles are important floor and wall covering ma-terials in the construction industry. In 1999 ca.4.5× 109 m2 were produced and laid world-wide. The most important market was Asia(1.9× 109 m2) followedbyEurope (109 m2) andAmerica (0.9× 109 m2).
Mainly earthenware tiles for indoor applica-tions (non-frost-resistant porous tiles with a wa-ter absorption of ca. 25 % according to the EN87 [23] and frost-resistant stoneware tiles (non-porous tiles with a water absorption of ca. 1 %)for indoor and outdoor applications are used.Different types of natural stones are installedfor indoor and outdoor applications. Nowadays,
Dry Mortars 17
the hard-pressed fully vitrified tiles (porcelaintiles) with an extremely low water absorption(< 0.1 %) and an excellent scratch, wear, andweather resistance, as well as glass tiles, are be-ing increasingly used, mainly for outdoor appli-cations and forfloors. In addition there is a strongtrend to use tiles in larger sizes (large-formattedtile, up to 40× 40 cm).
Ceramic tiles and natural stones previouslywere exclusively laid with the thick-bed mortartechnique based on job-site-mixed mortars. Inthismethod, sand and cement aremixed togetheron the job site to produce a simple cementmortarwith a cement/sand ratio of ca. 1/4 to 1/5. Afterapplying (buttering) this mortar on the reverseside of the water-(pre)soaked or prewetted tilein a thickness of 15 – 30mm, the tile butteredwith the mortar is pressed to the prewetted sur-face to be tiled. The tiles are tapped to ensureuniform flatness of the tile surface, and thus afinal mortar bed of 10 – 25mm is obtained. Thisprocedure not only causes a compaction of themortar, but leads in addition to the migration ofthe fine cement particles into the porous reverseside of the tiles and into the porous substrate.In this way a mechanical fixation or anchoringof the tile in the mortar bed is assured, as wellas anchoring of the mortar on the substrate aftercuring of the cement. Because this simple typeof mortar has no slip resistance, tiling must bestarted at the bottom, and spacers must be usedto obtain regular joints between the tiles.
However this method is a very time-, cost-and,material-consuming processwhich requiresexperienced craftsmen. They have to decidewhether the substrate and the tiles are suitablefor using this method, a certain soaking time ofthe tiles is required depending on their porosity,the mortar must bemixed in the correct ratio andconsistency, and the right amount of mortar hasto be applied on the reverse side of the tile be-fore it is laid. More significantly, there are a lotof technical restrictions in using this techniquein the modern building industry. For example,only porous and relatively small format tiles canbe laid on porous, solid, and strong mineral sur-faces (backgrounds) with this method due to theneed for mechanical anchoring of the mortar.
Therefore, the thin-bed mortar technique to-day has replaced the thick-bed mortar methodin most industrialized countries. After thepolymer-modified prepacked dry-mix mortarhas been gaugedwithwater, it can be applied to alarge area of the surface to be tiledwith a notchedtrowel (floating technique) to give a ribbed mor-tar bed of uniform thickness. Due to the goodwater retention capacity of the thin-bed mortar(effect of cellulose ether), neither the tiles northe substrate (background) have to be presoakedor prewetted. The tiles are then pressed into themortar bed with a slightly twisting action. If theadhesive mortar is formulated in the appropriateway by using adequate additives, tiles that havejust been laid in the fresh mortar bed will notslip. Thus, the insertion of spacers between thetiles is not necessary and tiling can be carriedout from the top to the bottom. This techniquecreates an adhesive mortar bed of ca. 2 – 4mmthickness, depending on the dimensions of thetrowel notches used (usually 6× 6× 6mm, de-pending on the size of the tiles and the flatness ofthe substrate). The thin-bed mortar technique isthus more cost-effective than its thick-bed coun-terpart. It also uses less material, can be appliedmore universally, and its execution is simpler,faster, and safer. This is even true in cases wherethe background is uneven and has to be coatedor levelled with an equalization mortar first.
With this thin-bed technique (Fig. 8) usingspecially designed prepacked dry-mix adhe-sive mortars, all technical demands of modernbuilding industry using different types of back-grounds and covering materials under differentand extreme climatic conditions can be satis-fied. Today there is wide range of ceramic-tileadhesives available, depending on the substrateto be tiled and the tiles being used: standardand flexible, normal- and fast-setting, as wellas special adhesives such as white mortars forfixing natural stones, waterproofing adhesives,flow-bed mortars for floor tiling, gypsum-basedadhesives, and high-flexibility mortars for freshscreeds.
18 Dry Mortars
Figure 8. Application of a thin-bed ceramic tile adhesive(spreading the adhesive mortar with a notched trowel ona wall to be covered with ceramic tiles); picture: WackerPolymer Systems
Dry-mix mortars for thin-bed tiling must ful-fill technical requirements such as good work-ability characteristics, good water-retention ca-pability, long open time and adjustability timeeven at high temperatures, and good non-sagproperties. After curing, the cement-based ad-hesive mortar must provide a good adhesive andcohesive bond strength between all types of cov-ering materials (e.g., natural stones and all kindof ceramic tiles) and various backgrounds (e.g.,concrete surfaces, brickwork, lime – cement ren-ders and base coats, gypsum, wood, old tile sur-faces, gypsum wallboards, aerated lightweightconcrete, particle boards, etc.). This must beguaranteed even after exposure to frost, damp-ness, and even permanent immersion inwater. Inaddition to good adhesion, the thin-bed adhesivemortar must have sufficient flexibility to absorband reduce possible tensions between the back-ground and the tiles caused by different thermalexpansion coefficients of the covering materialsand the substrates aswell as possiblemovementsof the background.
These overall characteristics of a thin-bed ad-hesivemortar can only be achieved by prepackedpolymer-modified cementitious dry-mix mor-tars containing cellulose ethers as additives andredispersible powders as a polymer bindingagent. Typical basic formulations for a standardand a high quality flexible ceramic tile adhesiveare given in Table 5.
Table 5. Typical formulations for ceramic-tile adhesives
The most important technical requirementsin Europe for a ceramic tile adhesive (besidesworkability) and the test methods are summa-rized in Table 6.
6.4. Tile Grouts
Tile grouts are used to fill the joints between tilesor natural stones laid onwalls or floors. Cement-based tile grouts with appropriate formulationsare suitable for interior and for exterior appli-cation. In combination with the tiles they mustprovide an optically attractive suface and mustperform physical functions. The tile grout mustbe capable of reducing stresses within the wholewall or floor covering material, it must protectthe materials and layers under the tiled surfaceagainst mechanical damage and the negative in-fluences ofwater penetrating into thewhole con-struction. Thus a cementitious grout must havegood adhesion to the edges of the tiles, lowshrinkage, sufficient deformability or flexibility,high abrasion resistance, good toughness and co-hesion, low water absorption, and an excellentworkability (low stickiness of the wet mortar).According to their application, two main typesof tile grouts can be classified (Table 7).
For white and colored tile grouts, white ce-ment is used as amineral binder. Alkali-resistantpigments such as iron oxides should be used forcolored grouts. Appropriate carbonate fillers canbe used additionally or even exclusively insteadof silica sand as a filler. To reduce the risk ofefflorescence, the use of hydrophobing agents isvery helpful, and microsilica or trass can addi-tionally be added. The main technical require-ments for tile grouts are summarized in Table 8.
Dry Mortars 19
Table 6. Summary of European standards for ceramic-tile adhesives
Test Standard Requirements
Definitions and terminology EN 1322Slip resistance EN 1308 < 0.5mmWetting capability EN 1347Tensile adhesion strength EN 1348 Minimum requirement: > 0.5N/mm2 for all
storage conditionsStorage conditions: standard conditions: 28 d sc∗ waterimmersion: 7 d sc + 21 d in water heat aging: 14 d sc + 14 d70 ◦C +1 d sc freeze-thaw: 7 d sc + 21 d in water + 25cyclesfreeze-thaw
Additional requirement: > 1.0N/mm2 for allstorage conditions
Heat-aging test: 14 d sc + 14 d 70 ◦C + 1 d scFreeze – thaw resistance: 7 d sc + 21 d in water + 25 cyclesfeeze – thaw)Open time EN 1346 > 20min; or > 30minDeformability/flexibility with transverse deformation test EN 12002Adhesives for tiles – definitions and specifications EN 12004
∗A: standard gray tile grout for interior and exterior use, B:high-quality, pigmented, smooth-surface tile grout for interiorand exterior use.
6.5. Exterior Thermal InsulationComposite Systems
External thermal insulation composite systems(ETICS) or external insulation and finishing sys-tems (EIFS) were developed in Europe in theearly 1970s. The first oil crisis in Germany in1973, together with financial support from thegovernment for homeowners, helped tremen-dously to promote the system. From 1973 to1993 ca. 300× 106 m2 of facades in the FederalRepublic of Germany were equipped with ET-ICS [24], and more than 18× 109 L of heatingoil was thus saved. Apart from saving energy,emissions of pollutants and CO2 are reduced.
ETICS also significantly increases the com-fort while living in a building due to a more con-stant temperature and humidity over the seasons.It reduces significantly building damages by de-
creasing the temperature variations in the exter-nal wall construction and combined with lesscondensation of dampness allows to reduce theoverall building costs. Therefore, thermal insu-lation is not only a sensible investment in newbuildings, but also a good renovation measure,especially if the facade has to be renovated any-way.
The first ETICS, introduced in the 1970s,consisted of a dispersion-bound paste adhesiveto which cement was added at the constructionsite. This compound was used to fix expandedpolystyrene panels to the walls to be insulated.The same product and procedure was used toembed the fiber-glass mesh that serves as a rein-forcement in the reinforcement layer or base coaton top of the fixed thermal insulation panel. Inearlier years mainly dispersion-bound syntheticresin plasters were applied as a finishing coatafter the base coat had been primed.
However, in practicemanymistakes occurredwhen using this system, in particular during themixing of the dispersion-bound paste adhesivewith cement at the construction site. With thissystem it is not possible to always produce a ho-mogeneous mixture with a constant polymer tocement ratio, and adhesives and base coats withdifferent compositions are thus obtained. Thisresults in inadequate product characteristics andpossible damage to the facades due to insuffi-cient adhesive bond strength or flexibility. Thisargument also apply to the two-component sys-tems, inwhich awater-based dispersion is addedto dry-mix mortars at the construction site. For
20 Dry Mortars
Table 8. Important requirements, test methods, and standards for cement based tile grout mortars
Standard Requirements
Grouts for tiles – definitions and specifications prEN 13888Determination of water absorption prEN 12808-5 water absorption (WA) determined with 16× 4× 4 cm prisms;
requirements:fundamental characteristic: WA after 30min < 5 g; WA after240min < 10 gadditional characteristic: WA after 30min < 2 g; WA after 240min< 5 g
Determination of resistance to abrasion prEN 12808-2 abrasion tester according to EN102; requirements:fundamental characteristic: volume removed during test< 2000mm3
additional characteristic: volume removed during test < 1000mm3
Determination of shrinkage prEN 12808-4 shrinkage determined with 16× 4× 4 cm prisms after 28 d sc;requirement: < 2mm/m
Determination of flexural and compressive strength prEN 12808-3 flexural (FS) and compressive strength (CS) determined with16× 4× 4 cm prisms after 28 d sc and freeze – thaw cycles;requirements: FS> 3.5 N/mm2; CS> 15N/mm2
these reasons, togther with the above-mentionedprinciple disadvantages of two-pack systems, to-day thepolymer-modified cement baseddry-mixmortars have almost completely substituted allother systems for ETICS.
Classic ETICS consist of the following com-ponents:– Adhesive for fixing the thermal insulationpanels, mainly expanded polystyrene, on thewall (depending on instructions and techni-cal guidelines, additional mechanical fixingwith special dowels may be necessary).
– Base-coat for embedding the reinforcementmesh on top of the thermal insulation panels(mechanical protection of the thermal insu-lation panels).
– Mineral finishing coating (mainly cementi-tious plasters or stucco with different struc-tures).A typical formulation (in wt %) for the adhe-
sive and base-coat mortar is given in the follow-ing:
The combination of individual componentsof an ETICS must always be seen as a whole.Thus the adhesive, thermal insulation panels,embedding mortar, fiber mesh, primer (or key-coat if necessary), dowels (if an additional me-chanical fixing is required), and the finishing
coat must be carefully adjusted to each otherand must be tested and approved together as asystem. Therefore, it is not permitted to combineindividual components from different sources tocreate an ETICS which has not been tested andapproved as a whole system.
Figure 9 shows a typical composition of a ET-ICS.
Figure 9.Typical components of a ETICS (Wacker PolymerSystems)
To meet the technical requirements, ca.4 – 5 % of organic binder in form of a redis-
Dry Mortars 21
persible powder is used for the adhesive mor-tar and the base coat. This means that apartfrom the required good adhesion of the cemen-titious mortar on the substrate and on the insu-lating polystyrene panels, a sufficient deforma-bility (flexibility) and a high degree of impactresistance of the mortars are achieved as well.
A large choice of different materials and sys-tems are available nowadays as finishing coatsfor theETICS.Apart from the classic dispersion-bound plasters, available inmany structural vari-ations and colors, mainly mineral cement – limeplasters or stuccoes, silicate plasters, and to acertain extent silicone resin plasters are used.
Various countries have differing regulationsand specifications for ETICS. At present a Euro-pean standard is being prepared for external ther-mal insulation composite systems [draft fromEuropean Organisation for Technical Approvals(EOTA)]. It will describe all specifications forthe individual components of the system andthe overall composite system itself (e.g., phys-ical and construction specifications as well astechical requirements like water absorption, be-havior under hydrothermal stress, inflammabil-ity, water-vapor permeability, adhesive strength,impact resistance, etc.).
Worldwide, new thermal insulation regula-tions (e.g., WschVO in Germany [25]) further-more establishminimumrequirements for theK-value (thermal insulation value) of the externalwalls of new buildings. For concrete and brickswalls these binding minimum requirements canoften only bemet by the additional application ofan ETICS, and this will lead to a further growthin thermal insultation systems. Even in countrieswith an high average temperature, thermal insu-lation composite systems are becoming popularfor saving energy for air-conditioning.
6.6. Powder Paints
The use of liquid dispersion paints is wellknown and has proven itself in practice sincetheir invention in the 1950s, and today this isthe leading technology for interior and exteriorpaint application. As a sole binding agent forhis type of products aqueous dispersions basedon styrene – acrylate, vinyl acetate ethylene, orother copolymers are used.
In DIN 55945 surface coating materials suchas laquers and paints are defined, classified, andcharacterized. Paints according to this standardare compounds in liquid and pasty form, basedon solvents, binding agents, pigments, fillers,and additives, but including powder-form coat-ing materials as well. Paints can be classified as:
– Spray-applied powder coatings– Paints and coating materials in powder form(powder paints) to be mixed with water be-fore application
Powder paints were known for many decadesbefore the invention of the liquid dispersionpaints. In the early days of the powder paints thebinder was either of organic origin (e.g., distem-per paint based on glue) or of inorganic origin(e.g.,mineral paints basedon themineral bindershydrated lime and/or cement). For a long timethe mineral binder was modified with organicbinding agents (casein, cellulose ether, starchether) to improve the technical characteristicsof the mineral coating material.
Natural organic binders have since been re-placed with much more efficient synthetic poly-mer binders in the form of redispersible pow-ders, and this has again led to an increasing im-portance of powder paints. Redispersible pow-der as organic binder is used as the sole binder inpowder dispersion paints and for the modifica-tion of mineral powder paints based on cement,hydrated lime, or water glass (silicate powderpaints) to improve their technical performanceand durability.
Powder dispersion paints were first used onbuilding facades inAustria in the 1960s and laterin Germany. They provide almost the same char-acteristics as liquid dispersion paints, but offerall the advantages of a powder system. Powderdispersion paints are used for interior and exte-rior applications. The most important differencein formulation is the content of polymer binder.The higher the polymer content, the better theadhesion and the higher the wet-scrub resistanceof the paint.
Like typical dry-mix mortars, powder paintsare supplied in paper bags or in silos to the jobsite and are gauged with water befor use and areapplied by brush, roller or spraying.
22 Dry Mortars
Table 9. Important test methods and standards for (powder) paints
Standard Comments
Definitions DIN 55945 definitions, composition, types of painting materials,General requirements DIN 53778 general requirements concerning workability, capability of dilution,
tinting, compatibility with pigments, minimum temperature ofapplication, recoatability, gloss, hiding power
Water absorption EN ISO 15148 coefficient of water absorption W < 0.5 kgm2 h0.5 and W · Sd < 0.2kgmh0.5 for exterior application (EN ISO 15148 substitutes DIN 52617)
Water-vapor permeability EN ISO 12572 diffusion-equivalent air-layer thickness Sd < 2m (EN ISO 12572substitutes DIN 52615)
Wet-scrub resistance DIN 53778 > 1500 cycles for indoor application, > 5000 cycles for outdoorapplication and for scrub-resistant paints
Table 9 summarizes the most important stan-dards and technical requirements for powderpaints.
6.7. Cementitious WaterproofingSealing Slurries
Water in liquid or in vapor form is the most de-structive weathering element for building ma-terials such as concrete, masonry, and naturalstones.
Traditional sealing and waterproofing sys-tems (e.g., according to DIN 18195) include bi-tuminous materials, plastic waterproofing foils,and metal tapes for interior and exterior applica-tions. Different types of materials can be used toseal and protect the surface of buildings or theirstructural components against the intrusion ofdampness andwater.Nowadays products for thispurpose are based on reactive resins like epoxyand/or polyurethane, dispersions (paintable wa-terproofing membranes), and mineral binderslike cement, which are known as waterproofingmembranes or sealing slurries.
Cementitious waterproofing membraneshave been successfully used for more than40 years in Europe. The structures to be pro-tected were either exposed to periodic or long-term wetting (surface water, seepage water),low hydrostatic pressure (soil dampness), orin combination with appropriate engineeringeven high hydrostatic pressure. Cementitiousmembranes (slurries) are used to waterproofwet rooms and water tanks, and due to theirexcellent weathering resistance also for exteriorsurface protection. Further typical applicationsare the sealing and waterproofing of basement
walls, of swimming pools, as well as walls andfloors in bathrooms, and on balconies and ter-races as a waterproofing layer to be tiled over.Some of the main advantages of cement-basedwaterproofing membranes are their excellent re-sistance to water (even if exposed permanently),excellent long-term weathering resistance, goodscratch resistance, good load-carrying capacityand much higher water-vapor permeability thanmost of the other systems.
Figure 10 shows a typical application of acementitious waterproofing sealing slurry bybrush.
Figure 10. Typical application of a cementitious water-proofing sealing slurry by brush (Wacker Polymer Systems)
Cement-based waterproofing slurries areeasy to use, nontoxic, provide a fully bound andmonolithic surface without joints, and can be
Dry Mortars 23
easily applied on substrates with complex sur-face shapes. In contrast to other systems, ce-mentitious waterproofing slurries can even beused on damp and wet mineral surfaces. Theirphysical properties are also less temperature-dependent compared to bitumen-based materi-als. So far there are no standards available forthese alternative sealing products, but nationalguidelines of mortar associations are well ac-cepted in the building industry [26].
Simple, non-polymer-modified cement-based slurries are still used for protection againstsurface water, but they are not suitable for seal-ing against water under hydrostatic pressure.To improve the poor adhesion, the poor watertightness, and the extremely low deformabil-ity and flexibility of these unmodified systems,polymers are added in form of liquid disper-sions on the job site or as a redispersible powderalready mixed with the dry-mix mortar. Spe-cial additives in these dry mix mortars includewater-retention agents, thickening agents, andrheological additives.
Today standard or rigid mineral waterproof-ing slurries are polymer-modified, prepackeddry-mix mortars with a high cement and rela-tively low polymer (redispersible powder) con-tent. They are used for mineral substrates whichare dimensionally stable, sound, and solid with-out risk of crack formation, movement, or di-mensional changes such as shrinkage. Develop-ments in the late 1970s led in Europe to flexiblewaterproofing slurries, which to a certain extentare capable of bridging small cracks (up to ca.1mm) in the substrate. The flexibility of suchproducts strongly depends on the polymer to ce-ment ratio and on the flexibility of the polymeritself. Flexible and highly flexible waterproofingcementitious slurries are used on substrates thatare still subject to shrinkage, vibration, move-ment, stress, and crack formation, and on sub-strates that are difficult to coat, such as wood,steel, aerated lightweight blocks, and gypsum.Due to their high polymer content (up to 40wt%of the total formulation), they have a high dif-fusion resistance and are chemically resistant tochloride, sulfate ions, carbon dioxide, or otheraggressive substances. In central Europe flexiblecementitious waterproofing sealing slurries rep-resent the last domain for two-component (two-pack) systems, which are based on prepackeddry-mix mortar and liquid admixes. However,
even in these high-polymer products, there is astrong trend towards one-pack systems in formof polymer-modified dry-mix mortars.
6.8. Self-Leveling Underlayments andScreeds
Self-leveling underlayments (SLUs) are from atechnical perspective probably the most com-plex field for dry-mix mortars. On a given un-even substrate (i.e., screed or surface to be refur-bished), self-leveling mortars have to provide asuitable, smooth and solid substrate for apply-ing all kinds of flooring materials like carpets,wooden parquet, PVC, tiles, etc. Self-levelingunderlayments should be applicable in an easyand efficientmanner, even for large areas. There-fore, the SLU material has to have very goodflow characteristics, and self-leveling and self-smoothing properties. In addition, it should setand dry quickly so that the flooring material canbe applied on top of the hardened mortar afteronly a few hours. The SLU mortar should ad-here to all kinds of substrates and exhibit lowshrinkage, high compressive strength, and goodabrasion resistance.
The technical requirements for SLUs rangefrom very simple to highly sophisticated prod-ucts. They vary in thickness from a verythin layer of 1 – 10mm (feather finish, self-leveling/troweling mortars and underlays), upto 60mm for self-leveling screeds, which are al-ways applied bymachines (mixing and pumpingin one set up).
The screeds are used as a loadwearing base ina thickness from 30 to 80mm, and are thus high-volume-application mortars. These mortars canbe based on cement or gypsum (anhydrite) asmineral binder, the latter providing underlay-ments with a high dimensional stability (lowor even no shrinkage). The set time (“walk-over time”) of these materials varies from nor-mal/regular setting to fast-setting products. Nor-mally this depends on the requirements of a spe-cific job, that is, the flooring material can be laidon the SLU in a certain time frame. The shorterthe setting and drying time, and the thicker themortar is applied, the more complicated and ex-pensive the formulation becomes. Self-levelingcompounds for underlayments and screeds arebased on special hydraulic binders like Portland
24 Dry Mortars
cement (OPC), high-alumina cement (HAC),and gypsum (anhydrite), to achieve fast curingand drying by avoiding excessive shrinkage orexpansion.
So far there are no standards on self-levelingunderlayments (SLU) in Europe. However, thetechnique and its application have been wellknown formany years, and exclusively polymer-modified prepacked dry-mix mortars are usedfor this application.
6.9. Patching and Repair Mortars
Concrete is a very versatile, long-lasting, anddurable building and construction material if itis applied according to the state of the art. In thepast, and even today, unfortunately, repeated dis-regard of the fundamental principles of concreteand structural concrete application still leads tosevere and serious damage in the building indus-try. The cost of the repair of concrete structureshas dramatically increased over the last 30 yearsin all industrial countries. In Germany approxi-mately 20 % of the cost of the volume of struc-tural concrete work is attributed to the repairandmaintenance of existing buildings and struc-tures. The degradation of structural concrete iscaused by corrosion of the steel reinforcementdue to carbonation of concrete caused by atmo-spheric carbon dioxide and other aggressive me-dia (e.g., SO2, acid rain). The corroded steel re-inforcement increases in volume and splits offthe overlying concrete, thus destroying the struc-ture.
In the construction industry concrete repairwork can be classified into two types:
1) Repair of concrete which does not containsteel reinforcement and which does not haveload-bearing functions. It is normally car-ried out for aesthetic reasons (cosmetic re-pair work) only, with patching mortars orpatching compounds.
2) Repair and reconstruction of damaged rein-forced and load-bearing concrete structuresto maintain and reconstitute their structuralstability and function. This is carried out instages with different kind of mortars, whichare part of a “concrete rehabilitation system”(typical applications: repair work and reha-bilitation of bridges, parking decks, tunnels,etc).
Patchingmortars for reprofiling and cosmeticrepair are based on dry-mix mortars. Usuallycement-based mortars are used for indoor andoutdoor applications, whereas gypsum-basedproducts are only used for some specific indoorapplications (cosmetic repair), i.e., for fillingsmall holes, voids, cracks and cavities to restorethe original dimensions.
Toguarantee the durable and reliable repair ofstructural concrete, concrete rehabilitation sys-temsmust restore the corrosion protection of thesteel reinforcement (alkaline environment), re-profile the concrete structure, restore its load-bearing functions, and finally restore the protec-tion and thus durability of the whole construc-tion (protection against weathering and environ-mental damage caused by CO2, SO2, Cl2, de-icing salts, etc).
For the rehabilitation of structural concretethree types of mortars are used today: cement-based concrete mortars (CC; mostly applied asa shotcrete mortar), polymer (modified) cementconcrete (PCC) as prepacked dry-mix mortars,and epoxy cement concrete (ECC).
Today mainly PCC mortars are used for therehabilitation of concrete structures. These mor-tars can be applied by hand as well as by ma-chine, in a wet or even a dry spraying shotcreteprocess. Different kind of mortars delivered asdry-mix mortars with different characteristicsand functions are used as the components forconcrete rehabilitation systems:
– Primer and adhesion promoter for the rein-forced steel (polymer-modified cementitiousslurry or epoxy-based coating materials)
– Adhesion-promoter slurry (primer or key-coat) for the concrete to be repaired(polymer-modified cement based slurry)
– Restoration and reprofilingmortar (polymer-modified cement-based mortar)
– Fine stopper or smoothing mortar (polymer-modified cement-based mortar containingfine aggregates)
So far mainly national guidelines imple-mented by various organizations and regulationsare relevant to the requirements for concrete-repair systems [27]. Concrete rehabilitation sys-
Dry Mortars 25
tems are subjected to an official approval accord-ing to relevant laws and regular quality supervi-sion from independent test institutes.
7. Market Aspects
Precise data on worldwide production and con-sumption of dry mortars are not available, al-though for Germany, France, and Italy calcula-tions of the production are known. According toref. [28] the production of dry mortars in 2001was 10× 106 in Germany, 3× 106 in Italy, and2.7× 106 in France, and total consumption in
Western Europe was 30× 106 [28] or35 – 40× 106 according to other estimates.Worldwide consumption lies in the range of50 – 60× 106 [28], or (60 – 70)× 106 accordingto other estimates.
With increasing local working costs the ratiobetween dry mortars and mortars mixed on siteis increasing, as the application of dry mortarsrequires less time for the samework.Worldwidedry mortar consumption is increasing. Whilegrowth was strong in central Europe from the1960s to the 1980s, nowadays growth is mainlyin Eastern and Southern Europe, as well as inparts of the Asian and Latin American market.
8. References
Specific References1. A. Konietzko: “The Application of Modern
3. M. Guldner: “Production and Processing ofDry, Factory-Mixed, Mortars”, ZKG(Zement,Kalk,Gips) International, 52 (1999)no. 11, 628 – 631.
4. Data from EMO (European MortarOrganisation) and Wacker Polymer SystemsGmbH & Co. KG.
5. DIN 1164, Zement mit besonderenEigenschaften, Zusammensetzung,Anforderungen, Ubereinstimmungsnachweis(November 2000).
6. K. Krenkler, Chemie des Bauwesens, Band 1:Anorganische Chemie, Springer, Berlin, 1980.
7. J. A. H. Oates, Lime and Limestone,Wiley-VCH, Weinheim, 1998.
8. EN 459: Building Lime, Part 1: Definitions,Specifications and Conformity Criteria draftDIN EN 459-1, January 1999; Part 2: TestMethods draft DIN EN 459-2, January 1999;part 3: Conformity Evaluation, draft DIN EN459-3, January 1999.
9. D. Distler, Wassrige PolymerdispersionenWiley-VCH, Weinheim, 1999.
10. J. Schulze, Tonindustrie-Zeitung, 109 (1985)698.
11. K. Adler, Schweizer Baublatt 31 (1988) 44.12. L. Brandt, Cellulose Ethers, Ullmann’s
Encyclopedia of Industrial Chemistry, 5th ed.,vol. A 5, (1986) 461 – 488.
13. DIN 18555: Testing of Mortars with MineralBinders: Part 1: General, Sampling, TestMortar (September 1982); Part 2: FreshMortars Containing Aggregates with CompactStructures, Determination of Consistency,Density and Air Content (September 1982);Part 3: Hardened Mortars; Determination ofBinding Strength, Compressive Strength andDensity (September 1982); Part 4: HardenedMortars; Determination of Linear andTransverse Expansion and of DeformationCharacteristics of Mortars for Bricklaying byMeans of a Static Pressure Test (March 1986);Part 5: Hardened Mortars; Determination ofthe Bond Shear Strength of Mortars forBricklaying (March 1986); Part 6: HardenedMortars; Determination of the AdhesiveTensile Strength (November 1987); Part 7:Fresh Mortars; Determination of the WaterRetention Value by the Filter Plate Method(November 1987); Part 8: Fresh Mortars;Determination of the Workability Time andCorrection Time of Thin Bed Mortars forMasonry (November 1987); Part 9: HardenedMortars; Determination of the MortarCompressive Strength (September 1999).
14. DIN 52617: Determination of the WaterAbsorption Coefficient of Building Materials(May 1987).
15. Die Wirkung von Fließmitteln in hydraulischgebundenen Baustoffen. April 1997,SKW-Trostberg.
16. DIN 18557: Factory Mortar – Production,Control and Delivery (November 1997).
17. DIN 1168, Part 1: Gypsum Plasters, Terms andDefinition, Types and Application, Deliveryand Marking (January 1986); Part 2: GypsumBuilding Plasters; Requirements, Testing,Control (July 1975).
26 Dry Mortars
18. Draft DIN EN 13279; Gypsum and GypsumBased Building Plaster; Part 1: Definitions andRequirements (July 1998); Part 2: TestMethods (July 1998).
19. EN 1346: Adhesives for tiles – Determinationof open time (March 1999).
20. EN 1308: Adhesives for tiles – Determinationof slip (March 1999).
21. EN 1348: Adhesives for Tiles – Determinationof Tensile Adhesion Strength for CementitiousAdhesives (March 1999).
22. DIN 18550: Plaster; part 1: Terminology andRequirements (January 1985); Part 2: Plastersand Renderings out of Mortar with MineralBinders; Execution (January 1985); Part 3:Rendering; Rendering Systems for ThermalInsulation Purposes Made of MortarConsisting of Mineral Binders and ExpandedPolystyrene (EPS) as Aggregate (March1991); Part 4: Plaster and Rendering:Lightweight Plasters and Renderings;Execution (August 1993).
23. EN 87: Ceramic floor and walltiles – Definitions, Classification and Marking.
