High Performance Concrete

Unit-IV

Syllabus• High Performance Concrete: Concrete of High Grades,

various tests and application of high performance concrete

High Strength Concrete

• Based on the compressive strength; concrete is normally classified asnormal strength concrete, high strength concrete and ultra strengthconcrete. Indian standard recommended methods of mix design denotesthe boundary at 35 Mpa between normal strength and high strengthconcrete.

• The advent of pre-stressed concrete techniques has given impetus formaking concrete of higher strength. High strength concrete is necessaryfor the construction of high rise building and long span bridges.

• To achieve high strength, it necessary to use high cement content with thelowest possible W/C ratio which invariable affect the workability of themix. It should be remembered that high cement content may liberate largeheat of hydration causing rise in temperature which may affect settingand may result in excessive shrinkage.

High Strength Concrete

High Strength Concrete

• Various methods of producing high strength concrete are:• (i) Seeding• (ii) Revibration• (iii) Inhibiting Cracks• (iv) Using admixtures• (v) Sulphur impregnation• Seeding is a process of adding a small quantity of finely ground, fully hydrated

Portland cement to the fresh concrete mix.• Revibration of plastic concrete also improves the strength of concrete. Concrete

undergoes plastic shrinkage. Mixing water creates continuous capillary channelsand bleeding, reducing strength of concrete. Revibration removes all thesedefects and increases the strength of concrete.

Special methods of making high strength concrete

Seeding: This involves adding a small percentage of finely ground, fully hydrated Portland cementto the fresh concrete mix.

Revibration: Controlled revibration removes all the defects like bleeding, water accumulates ,plastic shrinkage, continuous capillary channels and increases the strength of concrete.

High speed slurry mixing: This process involves the advance preparation of cement - watermixture which is then blended with aggregate to produce concrete.

Use of admixtures: Use of water reducing agents are known to produce increased compressivestrength.

Inhibition of cracks: If the propagation of cracks is inhibited, thestrength will be higher.Concrete cubes made this way have yielded strength up to 105MPa.

Sulphur Impregnation: Satisfactory high strength concrete have beenproduced by impregnating low strength porous concrete by sulphur.

The sulphur infiltrated concrete has given strength up to 58MPa.

Use of Cementitious aggregates: Using slag as aggregate, strength up to25MPa has been obtained with water cement ratio 0.32.

High Strength Concrete

High Strength Concrete

• Various methods of producing high strength concrete are:• In conventional concrete, micro-cracks develop even before loading

because of drying shrinkage and other volume change. When thestructure is loaded the micro cracks open up and propagate. Theweakness can be removed by inclusion of small, closely spaced anduniformly dispersed fibres in concrete.

• Use of water reducing agents are known to produce increasedcompressive strength.

High Strength Concrete

High Performance Concrete

• The development of high performance concrete (HPC) is a giant stepin making concrete a high-tech material with enhancedcharacteristics and durability. High performance concrete is anengineered concrete obtained through a careful selection andproportioning of its constituents. The concrete is with the same basicingredients but has a totally different microstructure than ordinaryconcrete.

High Performance Concrete

• The low water cement ratio of HPC results in a very dense microstructurehaving a very fine and more or less well connected capillary system.

• The dense microstructure of HPC, makes the migration of aggressive ionsmore difficult, consequently HPC is more durable when exposed toaggregate environment conditions.

• High performance concrete can hence be defined as an engineeredconcrete with low water/ binder ratio to control its dimensional stabilityand when receive an adequate curing.

• The cementitious component of high or any combination of cementitiousmaterial such as slag, fly ash, silica fume, metakaolin and filler such as,limestones.

High Performance Concrete • Concrete compressive strength is closely related to the density of hardened

matrix. High performance concrete has also taught us that the coarseaggregate can be the weakest link in concrete when the strength ofhydrated cement paste is drastically increased by lowering thewater/binder ratio. In such case concrete failure can start to developwithin the coarse aggregate itself. As a consequence, there can beexceptions to the water/ binder ratio law when dealing with HPC. Whenthe concrete’s compressive strength is limited by the coarse aggregate, theonly way to get higher strength is to use a stronger aggregate.

• •If water curing is essential to develop the potential strength of cement inplain concrete, early water curing is crucial for high-performanceconcrete in order to avoid the rapid development of autogenous shrinkageand to control concrete dimensional stability, as explained below.

High Performance Concrete

• The hydration of cement paste is accompanied by an absolute volumecontraction that creates a very fine pore network within the hydratedcement paste. This network drains water from coarse capillaries,which start to dry out if no external water is supplied. Therefore, ifno drying is occurring and no external water is added during curing,the coarse capillaries will be empty of water as hydration progresses.This phenomenon is called self desiccation. The difference betweendrying and self-desiccation is that, when concrete dries waterevaporates to the atmosphere, while during-self desiccation waterstay within the concrete i.e. It only migrates towards the very finepores created by the volumetric contraction of the cement paste.

High Performance Concrete

High Performance Concrete

• HPC must be cured quite differently from ordinary concrete becauseof the difference in shrinkage behaviour. The ordinary concreteexhibits no autogeneous shrinkage whether it is water cured or not,where as HPC can experience significant autogenous shrinkage if itis not water cured during the hydration process. While curingmembranes provide adequate protection for ordinary concrete, theycan only help prevent the development of plastic shrinkage in HPC.They have no value in inhibiting autogenous shrinkage. Therefore,the most critical period for any HPC runs from placement orfinishing up to 2 to 3 days later

High Performance Concrete

High Performance Concrete

• During this time the most critical period is usually from 12 to 36hours. In fact, the short time during which efficient water curingmust be applied to HPC can be considered a significant advantageover ordinary concrete.. In fact, the short time during which efficientwater curing must be applied to HPC can be considered a significantadvantage over ordinary concrete. Water ponding, wheneverpossible or fogging are the best ways to cure HPC.

High Performance Concrete• Concrete is the most widely used construction material in India with annual

consumption exceeding 100 million cubic metres. It is well known thatconventional concrete designed on the basis of compressive strength does notmeet many functional requirements such as impermeability, resistance to frost,thermal cracking adequately.

• Conventional Portland cement concrete is found deficient in respect of:• Durability in severe environs (Shorter service life and require maintenance)• Time of construction (longer release time of forms and slower gain of strength)• Energy absorption capacity (for earthquake-resistant structures)• Repair and retrofitting jobs• High performance concrete (HPC) successfully meets the above requirement.

High Performance Concrete• High performance concrete (HPC) is a specialized series of concrete

designed to provide several benefits in the construction of concretestructures that cannot always be achieved routinely usingconventional ingredients, normal mixing and curing practices. In theother words a high performance concrete is a concrete in whichcertain characteristics are .developed for a particular application andenvironment, so that it will give excellent performance in thestructure in which it will be placed, in the environment to which itwill be exposed, and with the loads to which it will be subjectedduring its design life.

High Performance Concrete

“High performance Concrete”• It includes concrete that provides either substantially improved

resistance to environmental influences (durability in service) orsubstantially increased structural capacity while maintainingadequate durability. It may also include concrete, which significantlyreduces construction time without compromising long-termserviceability. While high strength concrete, aims at enhancingstrength and consequent advantages owing to improved strength,

• the term high-performance concrete (HPC) is used to refer toconcrete of required performance for the majority of constructionapplications.

“High performance Concrete”• In general, a “High performance Concrete” can be defined as

that concrete which has the highest durability for any givenstrength class, and comparison between the concretes ofdifferent strength classes is not appropriate. This means that,with the available knowledge, one can always strive toachieve a better (most durable) concrete required for aparticular application.

“High performance Concrete”• HPC is a concrete, which meets special performance, and

uniformity requirements that cannot be always achieved byusing only the conventional materials and normal mixing,placing, and curing practices. The performancerequirements may involve enhancement of placement andcompaction without segregation and long term mechanicalproperties, early age strength, toughness, volume stability,service life.

“High performance Concrete”• A High Performance concrete element is that which is designed to give optimized

performance characteristics for a given set of load, usage and exposure conditions,consistent with requirement of cost, service life and durability.

• High Performance concrete has,• (a) Very low porosity through a tight and refined pore structure of the cement paste.• (b) Very low permeability of the concrete• (c) High resistance to chemical attack.• (d) Low heat of hydration• (e) High early strength and continued strength development• (f) High workability and control of slump• (g) Low water binder ratio• (h) Low bleeding and plastic shrinkage

“High performance Concrete”

HPC Definition• American Concrete Institute (ACI)• A more broad definition of HPC was adopted by the ACI. HPC was

defined as concrete, which meets special performance anduniformity requirements that cannot be always be achieved routinelyby using only conventional materials and normal mixing, placingand curing practices. The requirements may involve enhancement ofplacement and compaction without segregation, long termmechanical properties, early age strength, volume stability or servicelife in severe environments. Concretes possessing many of thesecharacteristics often achieve higher strength. Therefore, HPC is oftenof high strength, but high strength concrete may not necessarily be ofhigh performance.

Composition of High Performance Concrete• The composition of HPC usually consists of cement, water, fine sand,

super-plasticizer, fly ash and silica fume. Sometimes, quartz flour andfibre are the components as well for HPC having ultra strength and ultraductility, respectively. The key elements of high performance concrete canbe

• summarized as follows:• Low water-to-cement ratio,• Large quantity of silica fume (and/or other fine mineral powders),• Small aggregates and fine sand,• High dosage of super-plasticizers,• Heat treatment and application of pressure which are necessary for ultra

high strength concrete after mixing (at curing stage).

Composition of High Performance Concrete

Key Features of High Performance Concrete

• HPC should have a better performance when compared tonormal strength concrete. Three of the key attributes to HPCare, strength, ductility and durability.

Strength

• In practice, concrete with a compressive strength less than 50MPa is regarded asNSC, while high strength concrete (HSC) may be defined as that having acompressive strength of about 50MPa.

• Recently, concrete with the compressive strength of more than 200MPa has beenachieved. Such concrete is defined as ultra high strength concrete. As thecompressive strength of concrete has been steadily increasing with ampleexperimental validation

• In general, the addition of admixture does not improve the concrete strengthonly. Usually, other aspects of performance, like ductility and durability, are alsoenhanced

Key Features of High Performance Concrete

Table shows the characteristics of different type of High Strength Concrete

with various compositions.

Ductility

• HPC is usually more brittle when compared with NSC,especially when high strength is the main focus of theperformance. Ductility can be improved by applying aconfining pressure on HPC. Besides confinement, theductility of HPC can be improved by altering its compositionthrough the addition of fibres in the design mix. Concretewith fibres inside is regarded as fibber reinforced concrete(FRC).

Ductility

Durability

• Many researchers have conducted investigations related toconcrete durability and have identified that the majority ofconcrete durability problems are related to the resistance ofconcrete to permeation of water and chemical ions. Suchproblems include corrosion of steel reinforcement, freeze-thaw damage, and alkaline-silica reaction.

Durability

• The permeability of concrete is a key factor influencing thedurability of concrete. Concrete permeability is dependenton permeability of each constituent material and itsgeometric arrangement.

• The permeability of cement paste is primarily related to porestructure, which includes porosity, pore size andconnectivity; while pore structure is a function of the water-to-cement ratio and the degree of hydration.

Durability

Methods for achieving High Performance• In general, better durability performance has been achieved by using

high-strength, low w/c ratio concrete. Though in this approach the designis based on strength and the result is better durability, it is desirable thatthe high performance, namely, the durability, is addressed directly byoptimizing critical parameters such as the practical size of the requiredmaterials.

• Two approaches to achieve durability through different techniques are asfollows.

• (1) Reducing the capillary pore system such that no fluid movement canoccur is the first approach. This is very difficult to realize and all concretewill have some interconnected pores.

• (2) Creating chemically active binding sites which prevent transport ofaggressive ions such as chlorides is the second more effective method.

Methods for achieving High Performance

Methods for achieving High Performance

Requirements for High-performance Characteristics

• Permeation is a major factor that causes prematuredeterioration of concrete structures.

• The provision of high-performance concrete must centre onminimizing permeation through proportioning methods andsuitable construction procedures (curing) to ensure that theexposure conditions do not cause ingress of moisture andother agents responsible for deterioration.

Requirements for High-performance Characteristics

• Permeation can be divided into three distinct but connected stages oftransportation of moisture, vapour, air, gases, or dissolved ions.

• It is important to identify the dominant transport phenomenon anddesign the mix proportion with the aim of reducing that transportmechanism which is dominant to a predefined acceptableperformance limit based on permeability.

salient high-performance requirements

Salient High-performance Requirements

Salient High-performance Requirements• The parameter to be controlled for achieving the required performance criteria could be

any of the following.• (1) Water/ (cement + mineral admixture) ratio• (2) Strength• (3) Densification of cement paste• (4) Elimination of bleeding• (5) Homogeneity of the mix• (6) Particle size distribution• (7) Dispersion of cement in the fresh mix• (8) Stronger transition zone• (9) Low free lime content• (10) Very little free water in hardened concrete

Salient High-performance Requirements

Material Selection

• The main ingredients of HPC are almost the same as that of conventionalconcrete.

• These are• 1) Cement• 2) Fine aggregate• 3) Coarse aggregate• 4) Water• 5) Mineral admixtures (fine filler and/or pozzolonic supplementary

cementations materials)• 6) Chemical admixtures (plasticizers, super plasticizers, retarders, air-

entraining agents)

Material SelectionCement• There are two important requirements for any cement:• (a) strength development with time and• (b) facilitating appropriate rheological characteristics when fresh.• 1) High C3A content in cement generally leads to a rapid loss of flow

in fresh concrete. Therefore, high C3A content should be avoided incements used for HPC.

• 2) The total amount of soluble sulphate present in cement is afundamental consideration for the suitability of cement for HPC.

Material Selection

• 3) The fineness of cement is thecritical parameter. Increasing finenessincreases early strength development,but may lead to rheologicaldeficiency.

• 4) The super-plasticizer used in HPCshould have long molecular chain inwhich the sulphate group occupiesthe beta position in the polycondensate of formaldehyde andmelamine sulphate or that ofnaphthalene sulphate.

• 5) The compatibility of cement withretarders, if used, is an importantrequirement.

Material Selection

Coarse aggregate• The important parameters of coarse aggregate that influence the

performance of concrete are its shape, texture and the maximum size.Since the aggregate is generally stronger than the paste, its strength is nota major factor for normal strength concrete, However, the aggregatestrength becomes important in the case of high performance concrete.Surface texture and mineralogy affect the bond between the aggregatesand the paste as well as the stress level at which micro cracking begins.The surface texture, therefore, may also affect the modulus of elasticity, theshape of the stress-strain curve and to a lesser degree, the compressivestrength of concrete. Since bond strength increases at a slower rate thancompressive strength, these effects will be more pronounced in Highstrength concrete. Tensile strengths may be very sensitive to differences inaggregate surface texture and surface area per unit volume.

Material Selection

Mineral admixtures• Mineral admixtures form an essential part of the high-performance

concrete mix. These are used for various purposes, depending upon theirproperties. More than the chemical composition, mineralogical andgranulometric characteristics determine the influence of mineraladmixture's role in enhancing properties of concrete. The fly ash (FA), theground granulated blast furnace slag (GGBS) and the silica fume (SF) hasbeen used widely as supplementary cementitious materials in highperformance concrete. These mineral admixtures, typically fly ash andsilica fume (also called condensed silica or micro silica), reduce thepermeability of concrete to carbon dioxide (CO2) and chloride-ionpenetration without much change in the total porosity.

Material Selection

• Fly ash used as a partial replacement for cement in concrete, provides verygood performance. Concrete is durable with continued increase incompressive strength beyond 28 days. There is little evidence ofcarbonation, it has low to average permeability and good resistance tochloride-ion penetration.

• Silica fume not only provides an extremely rapid pozzolanic reaction, butits very fine size also provides a beneficial contribution to concrete. Silicafume tends to improve both mechanical properties and durability. Silicafume concretes continue to gain strength under a variety of curingconditions, including unfavourable ones. Thus the concretes with silicafume appear to be more robust to early drying than similar concretes thatdo not contain silica fume.

• Silica fume is normally used in combination with high-range waterreducers and increases achievable strength levels dramatically.

summary of the characteristics of different mineral admixtures

summary of the characteristics of different mineral admixtures

summary of the characteristics of different mineral admixtures

summary of the characteristics of different mineral admixtures

Super-plasticizers or HRWR• The super-plasticizers are extensively used in HPCs with very low water cementitious

material ratios. In addition to de-flocculation of cement grains and increase in thefluidity, the other phenomena that are likely to be present are the following.

• (a) Induced electrostatic repulsion between particles.• (b) Dispersion of cement grains and consequent release of water trapped within cement

flocks.• (c) Reduction of surface tension of water.• (d) Development of lubrication film between particles.• (e) Inhibition of the surface hydration reaction of the cement particles, leaving more

water to fluidity the mix.• (f) Change in morphology of hydration products.• (g) Induced steric-hindrance preventing particle to particle contact.

summary of the characteristics of different mineral admixtures

• The main objectives for using super-plasticizers are the following.• (i) To produce highly dense concrete to ensure very low permeability with adequate resistance to

freezing-hawing.• (ii) To minimize the effect of heat of hydration by lowering the cement content.• (iii) To produce concrete with low air content and high workability to ensure high bond strength.• (iv) To lower the water-cement ratio in order to keep the effect of creep and shrinkage to a

minimum.• (v) To produce concrete of lowest possible porosity to protect it against external attacks.• (vi) To keep alkali content low enough for protection against alkali-aggregate reaction and to• keep sulphate and chloride contents as low as possible for prevention of reinforcement corrosion.• (vii) To produce pumpable yet non-segregating type concrete.

summary of the characteristics of different mineral admixtures

• Retarders• Retarders are, generally, recommended for HSC to minimize the

slump loss problem.• However, it is difficult to maintain compatibility between the

retarder and the super plasticizer.• Therefore, the Retarders are recommended only as a last resort; the

rheology is better controlled by the use of appropriate mineraladmixture (supplementary cementing material) discussed before

Mix Proportion• The main difference between mix designs of HPC and CC is the emphasis laid on• performance aspect also (in fresh as well as hardened stages of concrete) besides

strength, in case of HPC, whereas in design of CC mixes, strength of concrete is animportant criterion. By imposing the limitations on maximum water–cement ratio,minimum cement content, workability (slum, flow table, compaction factor, Vee-Beeconsistency), etc., it is sought to assure performance of CC; rarely any specific tests areconducted to measure the durability aspects of CC, during the mix design. In HPC,however, besides strength, durability considerations are given utmost importance. Toachieve high durability of HPC, the mix design of HPC should be based on the followingconsiderations:

• i) The water-binder (w/b) ratio should be as less as possible, preferably 0.3 and below.• ii) The workability of concrete mix should be enough to obtain good compaction (use

suitable• chemical admixtures such as super-plasticizer (SP)).• iii) The transition zone between aggregate and cement paste should be strengthened

(add fine• fillers such as silica fume (SF)).

Properties of High Performance ConcreteProperties of Fresh Concrete

• High performance concrete is characterized by special performance both short-and long-term and uniformity in behaviour. Such requirements cannot alwaysbe achieved by using only conventional materials or applying conventionalpractices.

• It is wrong to believe that the mechanical properties of high performanceconcrete are simply those of a stronger concrete. It is also as wrong to considerthat the mechanical properties of high-performance concrete can be deduced byextrapolating those of usual concretes as it would be wrong to consider thatnone of them are related. It is also wrong to apply blindly the relationshipslinking the mechanical properties of a usual concrete to its compressive strengththat were developed through the years for usual concretes found in codes andtext books.

Properties of High Performance Concrete

Workability• The workability of HPC is normally good, even at low slumps, and HPC

typically• pumps very well, due to the ample volume of cementing material and the

presence of chemical admixtures, particularly HRWR. Due to reducedwater-cementing material ratio no bleeding occurs. In the flowingconcrete bleeding is prevented by providing adequate fines in the concretemix. The cohesiveness of super-plasticized concrete is much better as aresult of better dispersion of cement particles. Cohesion is a function ofrheology of concrete mix, which is consequently improved. However,excessive dosages of super-plasticizer can induce some segregation, but ithas little effect on physical properties of hardened concrete.

Properties of High Performance ConcreteCuring• The compressive strength of HPC is less sensitive to temperature and relative

humidity than the normal strength concrete. However, tensile strength of HSChas been found to be more sensitive. The concrete containing very largequantities of ground granulated blast furnace slag requires longer moist curingtimes to develop adequate strength and is more sensitive to drying than plainPortland cement concretes.

• The higher internal temperatures frequently found with high early strength HPCcan lead to a rapid strength gain in concrete accompanied by a consequent gainin elastic modulus.

• The larger differential temperatures occurring within a stiffer concrete willcreate higher stresses and can cause more pronounced cracking than withnormal concrete. These cracks will occur, regardless of the method of curing,due to stress caused by differential temperatures.

Properties of High Performance Concrete

Properties of Hardened concrete• The behaviour of hardened concrete can be characterized in terms of

its short-term (essential instantaneous) and long-term properties.Short-term properties include strength in compression, tension andbond, and modulus of elasticity. The long-term properties includecreep, shrinkage, behaviour under fatigue, and durabilitycharacteristics such as porosity,

• permeability, freezing-thawing resistance, and abrasion resistance.

Application of High Performance Concrete• Application of High Performance Concrete• Major applications of HPC have been in the areas of pavements, long-span

bridges and high-rise buildings.• Pavements:• High Performance concrete is being increasingly used for highway pavements

due to the potential economic benefits that can be derived from the earlystrength gain of high performance concrete, its reduced permeability, increasedwear or abrasion resistance to steel studded tires and improved freeze-thawdurability. While the conventional normal strength concrete continue to be usedin most cases of pavement construction, different types of high performanceconcretes are being considered for pavement repairs for early opening to traffic,bridge deck overlays, and special applications in rehabilitation of structures andother developments.

Application of High Performance Concrete• A durable concrete called fast track concrete designed to give high strength at a very

early age without using special materials or techniques has been developed. The earlystrength is controlled by the water-cement ratio, cement content and its characteristics.Typically, a rich, low water content mix containing 1 to 2 per cent calcium chloride willproduce adequate strength and abrasion resistance for opening the pavement to trafficin 4-5 hours at temperatures above 100C. Fast track concrete paving (FTCP) technologycan be used for complete pavement reconstruction, partial replacement by an inlay of atleast one lane, strengthening of existing bituminous or concrete pavements by aconcrete overlay, rapid maintenance and reconstruction processes, and air-fieldpavements. The benefits of applying FTCP technology in such applications are: a reducedconstruction period, early opening of the pavement to traffic, and minimizing the use ofexpensive concrete paving plant. Flowable HSC overlays over thick bridge decks canmake the construction cost effective.

Application of High Performance Concrete• Bridges:• The use of high performance concrete would result in smaller loss pre-stress and

consequently larger permissible stress and smaller cross-section being achieved,i.e. it would enable the standard pre-stressed concrete girders to span longerdistances or to carry heavier loads. In addition, enhanced durability allowextended service life of the structure. In case of precast girders due to reducedweight the transportation and handling will be economical.

• Concrete structures are preferable for railway bridges to eliminate noise andvibration problems and minimize the maintenance cost.

• In the construction of the concrete bridges and highway structures a generalrequirement of using a water-binder ratio of less than 0.40 combined with theuse of silica fume so as to improve the chloride resistance against de-icing agentsand marine environment is recommended. This process improvement willprovide the advantages of reduced weight, increased strength and enhanceddurability

High-strength concrete is often used in bridges

Application of High Performance Concrete• High-rise Buildings• The reasons for using the high strength concrete in the area of high-rise

buildings are to reduce the dead load, the deflection, the vibration and the noise,and the maintenance cost.

• Miscellaneous Applications• Fibre reinforced concrete has been used with and without conventional

reinforcement in many field applications. These include bridge deck overlays,floor slabs, pavements and pavement overlays, refractories, hydraulic structures,thin shells, rock slope stabilization, mine tunnel linings and many precastproducts. The addition of steel fibres is known to improve most of themechanical properties of concrete, namely, its static and dynamic tensilestrengths, energy abrasion and toughness, and fatigue resistance. Hence properutilization of steel fibre reinforced concrete depends on the skill of the engineer.

High-performance concrete is often used in bridges and tall buildings

Materials Used in High-Performance ConcreteMaterial Primary contribution/Desired property

Portland cement Cementing material/durability

Blended cement Cementing material/durability/high strength

Fly ash Cementing material/durability/high strength

Slag Cementing material/durability/high strength

Silica fume Cementing material/durability/high strength

Calcined clay Cementing material/durability/high strength

Metakaolin Cementing material/durability/high strength

Calcined shale Cementing material/durability/high strength

Super plasticizers Flow ability

High-range water reducers Reduce water to cement ratio

Hydration control admixtures Control setting

Retarders Control setting

Accelerators Accelerate setting

Corrosion inhibitors Control steel corrosion

Water reducers Reduce cement and water content

Shrinkage reducers Reduce shrinkage

ASR inhibitors Control alkali-silica reactivity

Polymer/latex modifiers Durability

Optimally graded aggregate Improve workability and reduce paste demand

ConcreteEnvironment Deterioration

Impact

ResistanceConcreteEnvironment

Durable Concrete

(HPC)

The required durability characteristics are governed by the application ofconcrete and by conditions expected to be encountered at the time ofplacement. These characteristics should be listed.

References• Concrete Technology by: R.P. Rethaliya• Concrete Technology by . M.S. Shetty

• Internet websites• http://www.foundationsakc.org/

Thanks