This paper aims to investigate the thermal behavior of concrete containing propylene fibers (0.05, 0.075 and 0.1%) and micro-silica (5, 10 and 15% of cement weight).
A concrete mix is designed to gain 40 MPa strength in 28 days. It is exposed to heat to reach 600°C and kept for one hour. Tensile and compressive residual strengths are determined and compared.
Before heat strengths of concrete containing micro-silica and propylene are higher than those of conventional concrete (63% increase in compressive strength and 13% increase in tensile strength). In the case of post-fire strengths, the concrete containing micro-silica propylene has a higher compressive strength than conventional concrete (43.1% increase). The tensile strength of the specimens containing micro-silica and polypropylene fibers decreased significantly after heating, and it became lower than that of the control specimen (15.3% loss in the control specimen versus the average loss of 60.6 for other specimens). This can be attributed to the melting of polypropylene fibers during the heating process.
This paper is to investigate the residual strength of concrete mix containing 5–15% micro-silica and 0.05–0.1% polypropylene after exposure to a temperature of 600°C for an hour. The research is conducted by heating cubic and cylindrical specimens in the form of 12 mix designs, and the effect of simultaneous use of micro-silica and polypropylene, with different percentages, on the post-heat properties of concrete is investigated.
