Effect of Alumina and Silica Powder on the Performance of Light Expanded Clay Aggregates Concrete

Although structural light expanded clay aggregate concrete (LECA concrete) has properties of low weight, there is a problem that appears when achieving the strength requirements due to the weak strength of LECA aggregate. The importance of this research lies in improving the properties of LECA concrete by changing the types of LECA and the properties of the matrix. A portion of cement was replaced with alumina and silica powder. The practical programme included evaluation of compressive strength, water absorption, chloride migration coefficient, and corrosion of reinforced LECA concrete. The results indicated that compressive strength was greatly affected by changing the type of LECA aggregates, while there was no significant effect when changing the properties of the matrix. Meanwhile, silica powder contributed to improving the durability of LECA concrete by reducing water absorption and porosity, as well as reducing the chloride migration coefficient and achieving a 60% reduction in crack width from corrosion of steel reinforcement.