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Definition Polymer cement concretes have high tensile strength, good ductile behavior and high impact resistance capability due to the formation of a three dimensional polymer network through the hardened cementitious matrices. Because of the void-filling effect of this network and its bridging across cracks, the porosity decreases and pore radius are refined. Furthermore, the transition zone may be improved due to the adhesion of a polymer. A styrene butadiene rubber emulsion is incorporated to improve the ductile behavior and flexural strength of steel fibre reinforced cement concretes (SFC). Silica fume and fly ash are also used to enhance the densification of cementitious matrix. The mechanical properties, microstructure, porosity and pore size distribution of polymer modified steel fibre reinforced concrete are studied Mix Design Of SFC As with any other type of concrete, the mix proportions for SFC depend upon the requirements for a particular job, in terms of strength, workability, and so on. Several procedures for proportioning SFC mixes are available, which emphasize the workability of the resulting mix. However, there are some considerations that are particular to SFC. In general, SFC mixes contain higher cement contents and higher ratios of fine to coarse aggregate than do ordinary concretes, and so the mix design procedures the apply to conventional concrete may not be entirely applicable to SFC. Commonly, to reduce the quantity of cement, up to 35% of the cement may be replaced with fly ash (Nguyen Van, 2006). In addition, to improve the workability of higher fibre volume mixes, water reducing admixtures and, in particular, superplasticizers are often used, in conjunction with air entrainment
Applications Of SFC 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, shotcrete and now shotcrete also containing silica fume, airport pavements, bridge deck slab repairs, and so on. There has also been some recent experimental work on roller-compacted concrete (RCC) reinforced with steel fibres. The fibres themselves are, unfortunately, relatively expensive; a 1% steel fibre addition will approximately double the material costs of the concrete, and this has tended to limit the use of SFC to special applications.
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