High temperature performance of high strength concrete with rice husk

The purpose of this study is to determine the behaviour of high strength concrete under high temperature effects and propose solutions for problems involved. Nowadays, together with increase of modern building construction and technological advances, production of better concrete with higher strength is increasingly becoming an objective. Along with strength, durability is also of recent concern. Studies about behaviour of normal strength concrete under high temperature effects date back to 1920's; however, only during the last decades, behaviour of high strength concrete under the same effects has been studied. High temperature effects cause high vapour pressures to develop within concrete. These high vapour pressures, coupled with the low porosity of high strength concrete, cause it to exhibit explosive spalling behaviour. One of the most common methods to solve this problem is adding synthetic fibres with low melting points (such as polypropylene etc.,) into the concrete. Polypropylene fibres are not sustainable materials; their production causes environmental pollution and they release harmful gases due to decomposition in case of a fire. Rice husk is thought to be a suitable alternative as additive to them; because it is natural, easier to produce - obtain and it is likely to reduce the amount of harmful gas emissions in case of a fire. Rice husk is also a good adsorbent thanks to its chemical structure and it is estimated to be able to adsorb some harmful gases during the fire. In this study, the effects of polypropylene fibres and rice husk on mechanical, physical and thermophysical properties of high strength concrete after the concrete is exposed to high temperature effects are examined; and results obtained from the experiments with two additives are compared against each other. Keywords: High temperature, high strength concrete, polypropylene fibers, rice husk.