EFFECT OF FIBER ON COMPRESSIVE AND TENSILE STRENGTH OF AUTOCLAVED AERATED CONCRETE

Nowadays, new technologies and advanced producing technique materials result in reducing weight and cost of construction. Aerated concrete was first developed as a lightweight material consisting of combinations of cement and quicklime silica sand, slag, pulverized fly ash, or other siliceous fine aggregates, in the form of a fine powder. The powder is mixed with water to form a slurry, and air or other gas (usually hydrogen) is introduced into the slurry. Due to initial hydration of the cement, accelerated by the heat produced by the quicklime, the mixture sets acquired a uniform cellular structure. Air entraining can be used to reduce the density of concrete. In recent years AAC is one of the most popular building materials for infill panels and structural system of low-rise masonry building. It has many advantages. The advantages that made this building material are lightweight, energy saving, environmentally friendly, and cost effective, but this material still has some disadvantages, such as low mechanical properties which need to be improved. In this paper, the effects of fibrous additives of Carbon, Polypropylene, A-Glass and E-Glass on mechanical properties of Autoclaved Aerated Concrete (AAC) have been investigated experimentally. Due to the fact that fiber additives could improve mechanical properties, in this study, fibrous additives (such as Carbon, Polypropylene, A-glass, and E-glass) are used in making AAC. The results show that adding fibers have effects on fluidity and swelling of mixtures, which decrease by adding more fibers to the mixtures especially in the mixtures containing A-Glass and E-Glass. Adding 0.3% of carbon and polypropylene fibers could improve mechanical properties of AAC. However, the effect of carbon fibers is much higher than polypropylene fibers. Using A-glass fibers leads to reducing compressive and tensile strength. Adding 0.4% of A-glass reduces compressive amount to 32% and tensile strength amount to 29%: this could happen owing to the fact that the glass fiber reacts with alkaline environment and prevents the hydrogen release in the mix.