Polymer Concrete

PAPER PRESENTATION

ON

By

T.V.M. Akhilash Guptha B. Nareen Kumar

Email: akil_chari@yahoo.co.in nareen_rathode2007@yahoo.com

FaaDoOEngineers.com

2

ABSTRACT:

In Concrete Technolgy there are many types of Concretes here we are mainly discussing

about Polymer Concrerte. Polymer concrete is a composite material. A graded mixture

coarse and fine aggregates bound together by an appropriate organic resin system. Polymer

concrete is a relatively low-cost composite material system that has been developed to be a

technically viable alternative to porcelain for most high voltage electrical insulation

applications. Polymer composites appear as useful materials for repair and protection of

building structures, as well as for manufacturing pre-cast elements. In the case of pre-cast

elements as well as repair materials, the usefulness and durability of polymer composites

depend on the selection of the material composition for obtaining the composite with

controllable properties Polymer Concrete consists of a polymer binder which may be a

thermoplastic but more frequently is a thermosetting polymer, and a mineral filler such as

aggregate, gravel and crushed stone. PC has higher strength, greater resistance to chemicals

and corrosive agents lower water absorption and higher freeze-thaw stability than

conventional Portland cement concrete.

Polymer modified concrete may be divided into two classes; polymer impregnated

concrete and polymer cement concrete. The first is produced by impregnation of pre-cast

hardened Portland cement concrete with n monomer that is subsequently converted to solid

polymer. To produce the second, part of the cement binder of the concrete mix is replaced by

polymer Both have higher strength, lower water permeability, better resistance to chemical,

and greater freeze-thaw stability than conventional concrete.

FaaDoOEngineers.com

3

INTRODUCTION

Polymer concrete is a composite material in which the binder consists entirely of a synthetic

organic polymer. It is variously known as synthetic resin concrete, plastic resin concrete.

Because the use of a polymer instead of Portland cement represents a substantial increase in

cost, polymers should be used only in applications in which the higher cost can be justified

by superior properties, low labor cost or low energy requirements during processing and

handling. It is therefore important that architects and engineers have some knowledge of the

capabilities and limitations of PC materials in order to select the most appropriate and

economic product for a specific application. The first polymer concrete construction in the

worldis Concrerte-Roman_colosseum_red.

Concrerte-Roman_colosseum_red.

NATURE AND GENERAL PROPERTIES:

FaaDoOEngineers.com

4

Polymer concrete consists of a mineral filler and a polymer binder (which may be a

thermoplastic, but more frequently, it is a thermosetting polymer. When it is used as a filler,

the composite is referred to as a polymer mortar. Other fillers include crushed stone, gravel,

limestone, chalk, condensed silica fume, granite, quartz, clay, expanded glass, and metallic

fillers.

To produce PC, a monomer, a hardener and a catalyst are mixed with the filler. Other

ingredients added to the mix include plasticizers and fire retardants. To achieve the full

potential of polymer concrete products for certain applications, various fiber reinforcements

are used. These include

glass fiber,

glass fiber-based mats,

fabrics and

metal fibers.

The amount polymer binder used is generally small and is usually determined by the size of

the filler. Normal the polymer content will range from 5 to 15 percent of the total weight, but

if the filler is fine, up t 30 percent may be required.

Polymer concrete composites have generally good resistance to attack by chemicals and other

corrosive agents have very low water sorption properties. Portland cement concrete permits

the use of up to 50 percent less material. This puts polymer concrete on a competitive basis

with cement concrete in certain special applications. The chemical resistance and physical

properties are generally determined by the nature of the polymer binder a greater extent than

by the type and the amount of filler In turn, the properties of the matrix polymer are highly

dependent on time and the temperature to which it is exposed.

FaaDoOEngineers.com

5

The polymers most frequently used are based on four types of monomers systems: methyl

methacryl , polyester prepolymer-styrene, epoxide prepoiymer hardener and furfuryl alcohol.

The typical range of properties of PC products made with each of these four polymers is

presented in Table I. General characteristics and principal applications are described in

Table II.

Table I. Typical Range of Properties of Common PC Products and Portland Cement Concrete

___________________________________________________________________________________Thermal

Modulus CoefficientWater Compressive Tensile Flexural of of

Type of Density, Sorption Strength, Strength, Strength, Elasticity, Poisson ExpansionBinder kg/dm3 % MPa MPa MPa GPa Ratio 10GC-1

Poly(methylrnetha cry late)

2.0-2.4 0.05-0.60 70-210 9-11 30-35 35-40 0.22-0.33 10-19

Polyester 2.0-2.4 030-1.0 50-150 8-25 15-45 20-40 0.16-0.30 10-30

Epoxy 2.0-2.4 0.02-1 0 50-150 8-25 15-50 20-40 0.30 10-35

Furan polymer 1.6-1.7 0.20 48-64 7-8 - - - 3B-.61'

Concrete" 1.9-2.5 5-8 13-35 1.5-35 2-8 20-30 015-0.20 10-12

Table II General Characteristics And Applications of Polymer Concrete Products

___________________________________________________________________________

Type of Binder Used in PC General Characteristics Typical Applications

Poly (methylmethacrylate) Low tendency to absorb

water; thus high freeze-thaw

resistance : low rate of

shrinkage during and after

Used in the manufacture of

stair units, façade plates,

sanitary products for

curbstones

FaaDoOEngineers.com

6

setting; very good chemical

resistance and outdoor

durability

Polyester Relatively strong, good

adhesion to other materials,

good chemical and freeze-

thaw resistance, but have

high-setting and post-setting

shrinkage.

Because of lower cost, widely

used in panels for public and

commercial buildings, floor

tiles, pipes, stairs, various pre-

cast and cast-in applications in

construction works.

Epoxy Strong adhesion to most

building materials; low

shrinkage; superior chemical

resistance; low water

sorption.

Epoxy polymer products are

relatively costly; they are

mainly used in special

applications, including use in

mortar for industrial flooring.

Furan-based polymer Composite materials with

high resistance to chemicals,

strong resistance to polar

organic liquids.

Furan polymer mortars and

grouts are used for brick

floors.

.

MATERIALS AND TESTING PROGRAM

Based on workability, polymer content for GFRPC and CFRPC were determined to be 18%and 20% respectively. Fiber content for both the matrices was varied up to 6%. CIGMATstandards (CIGMAT PC1-01, CIGMAT PC2-01, CIGMAT PC3-01) were followed forspecimen preparations, compression test and tension test. Destructive tests were performed indisplacement-controlled mode.

TEST RESULTS AND CONCLUSIONS

Based on the experimental study the following conclusions can be drawn:

FaaDoOEngineers.com

7

Adding 6% glass fibers required 18% polymer in the GFRPC system for goodworkability. Glass fibers increased the failure strain, peak strength and modulus incompression and tension.

Adding 6% PAN based carbon fibers required 20% polymer to develop a workableCFRPC. The addition of carbon fibers increased the failure strain, but strength andmodulus decreased. In tension, it increased the tensile strain, modulus and strength.Carbon fibers also increased the failure strain in compression, but reduced thestrength and modulus.

0

10

20

30

40

50

60

70

80

90

0 0.2 0.4 0.6 0.8 1

Strain,%

Str

ess

,MP

a

PC

GFRPC

CFRPC

Compression Test

0

2

4

6

8

10

12

14

16

0 0.05 0.1 0.15

Strain,%

Str

es

s,M

Pa

PC

GFRPC

CFRPC

Tension Test

Acrylic Polymer Concrete:

The most common acrylic polymer is poly, obtained by polymerization of methyl

methacrylate. PC made with this acrylic polymer as a binder is versatile material,has

FaaDoOEngineers.com

8

excellent weathering resistance

good waterproofing properties

good chemical resistance and

relatively low setting shrinkage

its coefficient of thermal expansion is equivalent to that of Portland cement concrete.

Because of its very low tendency to absorb water, acrylic PC has a very high freeze-thaw

resistance.

Polyester Polymer Concrete :

Because of low cost, the most widely used polymer-binders are based on unsaturated

polyester polymer. In most applications, the polyester binder is a general purpose,

unsaturated polyester prepolymer formulation. The chemical reaction is called cross-linking,

the production process associated with it is referred to as curing, and the resulting polymer

binder is a thermosetting polymer.

Polyester PC has good mechanical strength, relatively good adhesion to other materials, and

freeze-thaw resistance. Polyester PC is used in various pre-cast and cast-in place applications

in constructs works, public and commercial buildings, floor tiles, sewer pipes and stairs.

Epoxy Polymer Concrete :

Epoxy binder like polyester, is a thermosetting polymer. The epoxy polymer can be hardened

with a variety of curing agents, the most frequently used being polyamines. The use of

polyamine hardeners results in PC products with the highest chemicals resistance. Other

curing agents are polyamides and polysulfide polymers. Epoxy PC products cured with

polyamides give greater flexibility.

FaaDoOEngineers.com

9

Epoxy PC exhibits high strength, low-setting and post-setting shrinkage, high chemical

resistance, good fatigue and creep resistance. Because they are relatively expensive, epoxy

polymers have not been used very widely as binders in PC products. Therefore, epoxy PC is

used for special applications. Epoxy PC reinforced with glass, carbon or boron fiber is used

in the fabrication of translucent panels, boat hulls and automobile bodies.

Furan Polymer Concrete :

Furan polymers are based on furfuryl alcohol, which is derived from agricultural residues

such a corn cobs, rice hulls, oat hulls or sugar cane bagasse. The furan pre-polymer is usually

cross-linked with furfuryl alcohol, furfuraldehyde to yield thermosetting polymers, high

resistant to most aqueous acidic or basic solutions and strong solvents such as ketones,

aromatics, and chlorinated compounds. The furan polymers are used as binders in mortars

and grouts to achieve chemically resistant brick floors and linings. In addition to exhibiting

superior chemical resistance, these floors have excellent resistance to elevated temperatures

and extreme thermal shock.

Polymerization :

Polymer- modified cementitious materials date back more than 70 years. In the 194G's they

were developed for use on ships' decks and bridges. Polymers arc made from simple organic

molecules that combine to form more complex structures through a process called

polymerization. The polymers are dispersed in water. These are added to hydraulic cement,

with or without aggregate or admixtures, depending on trip desired result.

FaaDoOEngineers.com

10

Advantages of adding polymers to concrete :

In Polymer- Modified Concrete, a report by the American Concrete Institute. Lists these

advantages to polymer concrete:

• Increased bond strength

• Freeze/thaw resistance

• Abrasion resistance

• Flexural and tensile strengths

• Reduced permeability and elastic modulus

How it works :

To the normal process of cement hydration, polymer modifications add a process of

coalescence. As cement hardens, there form small spaces between the aggregate particles.

These spaces arc what allow water to penetrate, and do damage in freezing conditions.

Polymer particles coalesce to fill these voids. Thai's why the concrete becomes less

permeable and better protected against freeing. Interestingly, polymer concrete does not

produce bleed water. It makes an excellent overlay because it needs very little finishing. It is

more accurate to say that it dries, than to call it curing. For that reason that it is used to

resurface concrete.

Applications & Advantages :

There are several chemical systems for polymer concrete and mortar. Acrylic binders provide

excellent environmental resistance and fast setting times. Epoxy resins exhibit high strength

and low shrinkage during curing. They also provide toughness and resistance to chemical and

environmental damage. Furan resins are formed from the polymerization or poly

condensation of furfural, furfural alcohol, or other compounds containing a furan ring. They

are commonly used in foundry binders, grinding wheels, refractories and other high-

FaaDoOEngineers.com

11

temperature applications Polymers resins are used in place of phenolics fiberboard binder

applications. Polyurethane provides excellent flexibility, impact resistance and durability.

Other chemical systems for polymer concrete and mortar include silicone, polyester, and

vinyl ester.

The subject of polymer concrete has generated a lot of interest among researchers during the

past decade. This is due to the many advantages that polymer concrete pavement offers

compared to regular portland cement concrete. The advantages of polymer concrete, when

compared to portland cement concrete include, quick curing and setting, reduced moisture

sensitivity and permeability and improved mechanical properties resulting in reduced

pavement thickness to support the same load. These advantages will lead to attractive life

cycle cost benefits. Material properties and mix designs for PC with epoxy,

methylmethacrylate and Polyester as the binder material have been investigated. It has been

shown in this study that increased material cost of PC can be offset by the reduced thickness

of the pavement. In order to develop life cycle cost information, it is necessary to obtain field

performance data of PC pavement, especially in the composite design mode.

Applicaton of Polymer Impregnated Concrerte:

Keeping in view the numerous beneficial properties of PIC it is found useful in a

large no of applications some of which have been listed &discussed below

a) Prefabricated structural elementsb) Prestressed Concretec) Marine worksd) Desalination plantse) Sewage works – Pipe & Disposal Works

a) Prefabricated structural elements:For solving the tremendous problems of Urban housing shortage,

maintaining , quality econmy and speed ,builders had to fall back on prefabricatedtechniques of construction. At present due to the low strength of conventional concrete, theprefabricated sections are large and heavy ,resulting in costly handling and erection. Thesereasons have prevented wide adoption of prefabrication in many countries.

At present, the technique of polymer impregnation is ideally suited for precast concrete .Itwill find unquestionable use in industrialization if building components .Owning to strength ,much thinner &lighter sections could be used which enables easy handling and erection.

FaaDoOEngineers.com

12

b) Prestressed Concrete :Further development in prestressed concrete inability to produse high strength

concrete, compatible with the high tensile steel available for prestressing .Since PIC providesa high compressive strength of the order of 100 to 140 Mpa will be possible to use it forlarger spans and for heavier loads.Low creep properties of PIC willl also make it goodmaterial for prestressed concrerte

c) Marine Works :Aggressive nature of sea water ,abrasive and leaching action of waves and

inherent porosity ,impair the durability of conventional concrerte in marine works. PIC,possessing high surface hardness ,very low permiabilty and greatly increased resistance tochemical attack is a suitable material for marine works.

d) Deslination Plants :Deslination if sea water is being resorted augment the shortage of surface and

ground water in many countries .The material used in the construction of flash distillationvessels in such works has to withstand the corrosive effects of distilled water ,brine andvapour upto a temp of 143 C. Carbon steel vessels which are currently in use arecomparatively costly .

e) Sewage Disposal Works :It is common experience that concrete sewer pipes deteriorate due to attack of

effluents and when buried in sulphated infested soils. Further, in the sewage treatment plant,concrete structures are subjected to severe attack from corrosive gases particularly in sludgedigestion tanks.

f) Impregnation of Ferrocement Products :The Ferrrocement techniques of construction is being extensively used in

manufacture of boats, fishing trawlers , domestic water tanks .Application of Polymer-impregate concrete due to its high sulphate and high resistance will prove to suitablematerial in the ssituations .References :

1. A. Blaga and J.J. Beaudoin. "Polymer Modified Concrete", Division of Building

Research, National Research Council Canada, Canadian Building Digest 241, Ottawa,

2. A. Blaga. "Plastics", Division of Building Research, National Research Council Canada,

Canadian Building Digest 154. Ottawa, 1973

3. A. Blaga. "Thermoplastics" , Division of Building Research, National Research Council

Canada, Canadian Building Digest 158, Ottawa, 1974.

FaaDoOEngineers.com