Residual strength characteristics of polymer fibre concrete exposed to elevated temperature

Abstract

Mechanical properties of polymer based concrete exposed to high temperature effects are evaluated in the present study. Concrete mixtures were prepared using styrene butadiene rubber (SBR) latex and reinforced with polypropylene (PP) fibres. “Latex polymer modified concrete mixes consisting of different aggregate proportions, polymeric fibre contents (0.1 and 0.3% Vf) and fly ash contents (25 and 50%) were investigated for high temperature performance. Concrete specimens after required curing were subjected to different high temperature effects from 200°C to 800°C and the corresponding weight loss and residual strength was determined. In addition, the residual elastic modulus of polymer concretes was determined from the compressive stress-strain properties. Experimental observations showed that, compared to plain concrete the residual strength characteristics of polymer fibre concretes were affected when exposed to high temperature. Strength degradation occurred with increase in temperature and the test results indicated that the temperature sustainability of polypropylene fibre concretes were observed up to 200°C. A maximum compressive strength loss upto 56.75% for plain concrete and 9.87% for polymer fibre concrete was noticed when exposed to high temperature upto 800°C. Further, microscopic analysis of fibre concretes exposed to high temperature showed possible melting of PP fibres resulting in filling the pore spaces which possibly improved the matrix hardening. Also, the high volume fibre incorporated concrete mixes showed maximum residual strength gain due to favourable matrix strengthening and demonstrated high temperature performance of polymer concretes.