This research aims to utilize recycled rice straw and rice husk to produce environmentally friendly concrete with optimum
properties. An experimental program was conducted which consisted of three phases. Rice straw and rice husk were treated
by different methods to obtain rice straw ash (RSA), rice husk ash (RHA) and rice straw (RS) which were used as partial
cement replacement in concrete mixes. Chemical treatment was made for rice straw and the test results showed that this
treatment managed to produce pure silica without emission of carbon monoxide. Concrete mixes containing RS were exposed
to high temperatures of 300°C, 500°C and 700°C for 1 and 2 hours. Fresh and hardened concrete tests were made to investigate
the effect of cement replacement with different percentages of RS, RSA and RHA on concrete properties at normal and
elevated temperatures. The obtained test results demonstrated the improvement of physical and mechanical properties of
concrete, especially at high temperatures.