Behavior of concrete using alccofine and nano-silica under elevated temperature

Fire protection is a critical concern since it can occur at any time because of naturally occurring or human threats. Concrete is proven to be excellent fire-resistant construction material, but spalling and infinite cracking occur if exposed to fire for a long period. In this paper effect of high temperature on concrete using alccofine (Al) and nano-silica (Ns) is examined for M40, M50, and M60 concrete grade. Residual compressive strength (RCS), % weight loss and spalling & color change of concrete cubes exposed to the fire temperatures of 200ºC, 400ºC, 600ºC, 800ºC & 1000ºC for the period of 4, 8 and 12 hrs are studied. Results have shown that the addition of alccofine (Al) and nano-silica (Ns) to concrete decreased weight and compressive strength. The increase in temperature above 600ºC affected the compressive strength of the Al + Ns mixes more than control mixes. At 1000ºC, excessive micro-cracking is also observed. Increased fire duration substantially increased concrete degradation.