عنوان مقاله [English]
Light weight concrete was aimed of several investigations and developed in order to increase mechanical strength. In the present study, pozzolanic effect of micro silica on density and mechanical strength of light weight concretes is investigated. Results showed that density and strength will decrease due to Perlite increased and in contrast strength will increase because of micro silica increased. By increasing micro silica amount, concrete matrix will be become denser and more homogenous. Strength increasing is supposed to micro silica and calcium hydroxide reaction to and hydrous calcium silicate phase evolution. Scanning electron micrographs showed crack deflection toward Perlite particles and in contrast cracks passed from sand and cement phase boundaries. Pozzolanic effect of micro silica on phase evolution was investigated by XRD technique.