Chapter No 2 Introduction to Ferrocement

8/9/2019 Chapter No 2 Introduction to Ferrocement

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CHAPTER NO.2 INTRODUCTION TO FERROCEMENT

Chapter 2

INTRODUCTION TO FERROCEMENT

2.1 FERROCEMENT: DEFINATION AND HISTORICALBACKGROUND

2.1.1 Intro !"t#on $%&

The initial definition of ferrocement can be drawn from a patent application submitted by Joseph-Louis Lambot of France, in 1852. The patent for iron-cement,! containedthe followin" description#

$y in%ention shows a new product which helps to replace timber where it isendan"ered by wetness, as in wood floorin", water containers, and plant pots etc&.The new substance consists of a metal net of wire or stic's which are connected or formed li'e a fle(ible wo%en mat. ) "i%e this net a form which loo's in the best

possible way, similar to the articles ) want to create. Then ) put in hydraulic cement or similar bitumen tar or mi(, to fill up the *oints.Lambot built two rowboats in 18+8 and 18+ , in len"th respecti%ely about . m and

m /12 and foot0, 1. m /+ ft0 wide and 8 mm /1.5 in.0 thic', and disclosed his patent at the aris e(hibition in 1855 by showin" one of the boats. The first boat isnow at the ri"noles museum in France /Fi"ure 1.20. 3 typical modern %ersion of aferrocement canoe is shown in Fi" 1. .

/4ombination of iron and cement, destined to replace wood, called fer-cement!substitute for construction wood. $etallic "rid or s'eleton for a boat, a water tan', or an oran"e bo(.!0

STRENGTHENING OF REINFORCEMENT CONCRETE BEAM USING FERROCEMENTCAST INSITU LAMINATESDANISH AZAD AHTESHAM ALTAF IMRAN ASLAM MUHAMMAD UMERABDULLAH KHAN

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Joseph Louis Lambot was born May 22, ! ", in MinFort#sur#$r%ens an& &ie&$u%ust

2, !!', in (ri%no)es, Fran*e


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)n 188 a 6utch man, $r. oon, built a small craft of ferrocement, the 7eemeuw /or sea"ull0 and se%eral bar"es of reinforced mortar to carry ashes and refuse on water canals. The 7eemeuw was reported to be still operatin" at the 3msterdam oo in

1 8. )t is currently displayed in the loun"e of the 9ereeni"in" :ederland;s 4ement)ndustries; office in 3msterdam.

6urin" the First


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an"'o', Thailand. )n 1 5, the 3merican concrete )nstitute formed 4ommittee 5+ ,Ferrocement. )n 1 1, the )nternational Ferrocement =ociety was established /under the leadership of D. arma0 with headCuarters at 3)T in an"'o'.

2.1.2 De'n#t#on () ACI Co**#ttee +,-

The followin" definition of ferrocement was "i%en by 34) 4ommittee 5+ in a state-of-the-art report on ferrocement /34) 5+ D0 first published in 1 8> and still enforced

at time of this writin".Ferrocement is a type of thin wall reinforced concrete commonly constructed of hydraulic cement mortar reinforced with closely spaced layers of continuous andrelati%ely small si e wire mesh. The mesh may be made of metallic or other suitablematerials .E+

2.1.% S! e/te Re0#/e De'n#t#on


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ased on past e(perience and ad%ances in ferrocement, the author su""ests thefollowin" definition, which is an e(tension of that of 34) 4ommittee 5+ #

Ferrocement is a type of thin wall reinforced concrete commonly constructed of hydraulic cement mortar reinforced with closely spaced layers of continuous andrelati%ely small si e wire mesh. The mesh may be made of metallic or other suitablematerials. The fineness of the mortar matri( and its composition should be compatiblewith the mesh and armature system it is meant to encapsulate. The matri( may containdiscontinuous fibers.

2.1 A LICATIONS OF FERROCEMENT

)n its role as a thin reinforced concrete product and as a laminated cement-basedcomposite, ferrocement can be used in numerous applications, includin" newstructures and the repair and rehabilitation of e(istin" structures. E5

2.1.1 Mar#ne App #"at#on/$arine applications of ferrocement include boats, fishin" %essels, bar"es, doc's,car"o tu"s, flotation buoys, and water or fuel tan's. The 'ey criteria for such.

2.2 CONSTITUENT MATERIALS OF FERROCEMENT


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2.2.1 Ce*ent Mortar Matr#3: Co*po/#t#on anCo*pre//#0e Stren thThe hydraulic cement matri( for ferrocement should be desi"ned accordin" standardmi( desi"n procedures for mortar and concrete. )ts components "enerally include

ortland cement, fine a""re"ates /sand0, water, and %arious admi(tures. The materialsshould satisfy standards similar to those used for Cuality reinforced concreteconstruction, with particular attention paid to the type of application.


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2.2.2 S4e eta Stee

)n ferrocement construction s'eletal steel is often used in the form of welded wire

fabric, or simply as a "rid of steel wires, rods, or strands. =uch s'eletal reinforcementis needed to form the s'eletal of the shape of the structure to be built, around whichthe mesh layers are later attached. The use of s'eletal steel, when the thic'ness of ferrocement allows it, can be %ery cost affecti%e. )t acts as a spacer, leadin" to sa%in"sin mesh layers. )t also adds si"nificantly to the tensile and punchin" shear resistanceof ferrocement.

2.%.% Me/h Re#n5or"e*ent

Thus far steel meshes ha%e been the primary mesh reinforcement for ferrocement.Gowe%er, research on fiber reinforced polymeric or plastic meshes will brin"additional alternati%es and impetus to ferrocement construction.

=teel meshes for ferrocement include sCuare wo%en or welded meshes, chic'en wiremesh of he(a"onal shape, and e(panded metal lath or sheet similar to those used in

plaster and stucco applications /Fi"s. 1.1 a.b0. B(pect for e(panded metal mesh, allmeshes used are preferably "al%ani ed.


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2.% DISTINCT CHARACTERISTICS OF FERROCEMENT6ERSUS REINFORCED CONCRETE

3s stated in the definition, ferrocement is a type of reinforced concrete construction.


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2.,.% ro"e//#n 7 Man!5a"t!r#n 7 Ma#ntenan"e 7Repa#r

• 4onstruction methods for ferrocement are different from those for con%entional reinforced concrete.

• Ferrocement can accommodate a lower le%el of technolo"y thanreinforced concreteH it needs less mechani ation and less hea%yeCuipment. )t also can be amenable to as hi"h a le%el of industriali ation as reinforced concrete with less capital in%estment.

• Ferrocement is %ery easy to maintain and repair.•

For marine applications, ferrocement "enerally pro%ides a lower costsolution than wood, reinforced concrete, or polymeric composites. )n

boat buildin", it is definitely the choice o%er reinforced concrete.

2., SIMILARTIES BET8EEN FERROCEMENT ANDREINFORCED CONCRETE

There are numerous similarities between ferrocement and reinforced concrete. )naddition to the fact that both use similar matri( and reinforcement materials, they obey

the same principles of mechanics and can be modeled accordin" to the same theoriesHthey can be analy ed usin" similar techniCuesH and they can be desi"ned accordin" tothe same philosophy, such as the limit state desi"n philosophy to satisfy both ultimateand ser%iceability limit states. Ane must 'eep in mind, howe%er, that ferrocement can

be considered an e(treme boundary of reinforced concrete and, as such, scale effectsmay be si"nificant enou"h to differentiate them.E8


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2.+ 6OLUME FRACTION OF REINFORCEMENT

The %olume fraction of reinforcement is the ratio of %olume of reinforcement to the%olume of composite.

9er. I Deinforcement

9composite

)n the abo%e definition the %olume of reinforcement includes the s'eletal steel.Gowe%er, if the s'eletal steel is placed in the center of the ferrocement member and if

bendin" is considered, its influence may be i"nored. :e%ertheless, the s'eletal steelshould be considered in e%aluatin" the resistance of tensile members.E

2.+.1 S9!are or Re"tan ! ar Me/he/


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2. .1 FR Me/he/The diameter of a yarn of a fiber reinforced plastic or polymeric /FD 0 mesh /as of ate(tile yarn0 is "enerally "i%en in a unit called denier!. 3 denier is defined as thewei"ht in "rams of >>> meters of yarn. Gence a >>> m lon" yarn of 2>> denier would wei"h 2>>". For yarns or bundles of filaments of any cross section, round or not, it is often desirable to determine the eCui%alent diameter. ELet us consider a fiber or yarn with a denier %alue 6f. 6efine#


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3s a first appro(imation when the %olume fraction of reinforcement is small 3c can bereplaced by 3m in the abo%e eCuation, where 3m is the net area of matri(.

=r can be di%ided into two parts one associated with the lon"itudinal and the other withthe trans%erse direction, thus#

2.< DISTINCTI6E BEHA6IOR OF REINFORCEMENT INTENSION %!!&

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composites. )ndeed it can be shown that cement matrices de%elop micro crac's /penny Kshaped two-and three-dimensional surface crac's0 as soon as they are sub*ected totensile loadin".

:umerous e(perimental studies ha%e obser%ed that, e%erythin" else bein" eCual, thetensile stress at first crac'in" in ferrocement is directly related to the specific surfaceof reinforcement

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3 composite is a material made of at least two different components, resultin" in asyner"ism where the composite property of interest for a particular application is better than either of its components ta'en separately. Gere is a case in point# a plain mortar roofin" plate or a plain wire mesh, ta'en separately, will not, indi%idually ser%e thefunction of roofin" panelH the plain mortar plate will li'ely fail under any load and themesh by itself will not pro%ide protection a"ainst rain and other en%ironmental effectsHyet combined in a ferrocement composite, they can pro%ide the functions of load

bearin" and en%ironmental protection essential for a roofin" panel. E12


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2.1? AD6ANTAGES OF FERROCEMENT AS ACONSTRUCTION MATERIAL

3ll the benefits that are attributed to the use of concrete and reinforced concrete in theconstruction applications "enerally applied to ferrocement as well. Gowe%er, there areattributes that ma'e ferrocement a preferred material when compared to wood, masonry,reinforced concrete, steel, and fiber reinforced plastics. E1

1. Ferrocement is made of materials that are readily a%ailable in most countriesH shouldsteel meshes be in short supply, other in"enious reinforcin" systems made of *ute,sisal, bamboo, and the li'e can be used.

2. Ferrocement is suitable for a wide ran"e of construction techniCues, ran"in" fromself-help construction for housin" and a"ricultural structures, to hi"hly prefabricatedindustrial processes, includin" precast panels for housin", pipes, channels, and curtainwalls.

. 3t the low end, ferrocement reCuires a low le%el of technolo"y and common labor s'illsH because it is relati%ely li"ht wei"ht, it does not reCuire hea%y constructioneCuipment or plants.


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+. 3t the hi"h end, ferrocement is suited for industriali ed construction and hi"h le%elsof prefabrication, where its relati%e li"ht wei"ht compared to con%entional reinforcedconcrete is also a benefit.

5. Ferrocement can be fabricated in any desired shapeH it is particularly suitable for shells and free form shapes and has been used for domes, boats, housin" structures,and sculptures.

. Ferrocement, li'e concrete and masonry, is durable and resistant to the en%ironmentH itis non-flammableH is less prone to corrosion than steelH is not sensiti%e to humidityand, unli'e wood, does not rotH and has a si"nificantly lon"er ser%ice life than fiber reinforced plastics.

. Ferrocement can be easily maintained and repaired after dama"e.8. Ferrocement is cost effecti%e.

. 3ccordin" to a definition adopted by the ?nited :ations 4onference on Bn%ironmentand 6e%elopment, ferrocement can be considered an en%ironmentally soundtechnolo"y. Bn%ironmentally sound technolo"ies protect the en%ironment, are less

pollutin", use all resources in a more sustainable manner recycle more of their wastesand products and handle residual wastes in a more acceptable manner thantechnolo"ies for which they substitute. Ferrocement Cualifies in terms of usin" fewer resources and less ener"y, in bein" less pollutin", and in "eneratin" less waste.


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Chapter No 2 Introduction to Ferrocement

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