NAME- IMRAN ALI (110107076)

POLYMER MODIFIED

CONCRETE

Introduction The concept of polymer modification for cement

mortar and concrete is not so new, as in 1923 the first patent of the concept had already been issued to Cresson

(1)This patent refers to paving materials with natural rubber latexes, and cement was used as a filler. The first patent with the present concept of polymer modification was published by Lefebure

(2)In 1924. Since then, considerable research and development of polymer modification for cement, mortar and concrete have been conducted in various countries for 70 years or more. As a result, many effective polymer modification systems for cement mortar and concrete have been developed, and currently are used in various applications in the construction industry.

Polymer modification of concrete

To produce polymer-modified mortar and

concrete, mostly polymers in dispersion (latex or

emulsion) form are added to ordinary cement

mortar and concrete during mixing. Polymer-

modified mortar and concrete have considerable

attraction because their process technology is

very similar to that of ordinary cement mortar and

concrete.

The polymer dispersions widely used are styrene-

butadiene rubber (SBR)latex, ethylene-vinyl

acetate (EVA), and polyacrylic ester (PAE)

SBR Modified Concrete

SBR Polymer is the most widely used in concrete

shows the chemical structure of Styrene

butadiene Rubber latexes. Co-polymers of

butidine with styrene(styrene-butadine rubber

(SBR)), are a group of large-volume synthetic

rubbers

High adhesion occurs between the polymer films

that form and cement hydrates .This action gives

less strain compared to ordinary concrete and

improves the properties of concrete such as

flexural and compressive strength and gives also

a higher durability

cost Various ingredients with their cost to produce 1

Kg of polymer have been ,It can be , that the total

cost to produce 1 Kg of polymer combination of

ratio 4:4:1 came to be rs 10/Kg whereas the cost

of cheapest polymer available in the market

varies from rs 40 to 100/Kg. Thus substantial cost

saving can be achieved by using the said polymer

combinations developed during the

Tensile and compressive strength of

PMC

Tensile and compressive strengths of ordinary

concrete and polymer modified concrete using

varying proportions of PVA emulsion and subsidiary

Chemical that the polymer alteration resulted in an

increase in the flexural tensile and compressive

strength of the ordinary concrete. Highest tensile

strength i.e., 1,200 Psi with corresponding highest

compressive strength 12,400 Psi was achieved in

polymer-modified concrete with the ratio of 4:4:1 by

weight of PVA, AG and SBR, respectively

ADVANTAGES OF PMC

High performance ,low cost , great convenience ,

and excellent durability.

Rupture strength, tensile splitting strength, bond

strength and impermeability is higher by 28.6%,

37.5%, 55.3% and 77.2% than ordinary concrete

respectively

Smooth surface finishing.

Water proofing

Applications of PMC

The uses of SFC over the past thirty years have

been so varied and so widespread, that it is

difficult to categorize them. The most common

applications are pavements, tunnel linings,

pavements and slabs, shortcrete and now

shortcrete also containing silica fume, airport

pavements, bridge deck slab repairs, and so on.

Conclusion

1. SBR Addition of steel to a concrete will improve both its flexural and compressive strength. The strengths increase significantly with fiber content.

2. The flexural strength increases greatly when containing 3-10 wt.% SBR. The optimal use of SBR is 5 wt.%, which achieves the highest flexural strength. However, the compressive strength may decrease with the addition arrives 10 wt.%, a 16% reduction is observed.

3.Polymer films are observed in concretes when incorporating 5 or 10 wt.% SBR, and act as bridges across pores and cracks. Moreover, the polymer films in concrete incorporating 10 wt.% SBR are thicker and more coherent.

4. The pore size distribution curves of specimens exhibit at least two peaks, which locate in the ranges of 5-20 nm and 50-1000 nm, respectively. Higher addition of SBR leads to a larger peak magnitude in the range of 50-1000 nm.

5. The overall porosity increases with the increasing dosage of SBR.