The present paper focused on development of structural lightweight concrete by using light weight expanded clay aggregate (LECA) with unit weight of 1700 kg/m 3 to 1900 kg/m 3 and compressive strength of 40 MPa. In this study, investigation was done using LECA as coarse aggregate in concrete by replacing normal aggregate in three differing volume fractions i.e., 30%, 40% and 50% with different w/b ratios 0.40, 0.50 and 0.60 to produce lightweight expanded clay aggregate concrete (LECAC) with addition of chemical admixture. For that, concrete mix design was done using IS method and replacement of lightweight aggregate was calculated based on volume batching. The effect of mineral admixture (i.e., 10% microsilica) on the properties of lightweight expanded clay aggregate concrete and normal weight aggregate concrete such as workability of fresh concrete, compressive strength and flexural strength of concrete were compared. The studies also include the effect of elevated temperature on light weight expanded clay aggregate concrete and normal weight aggregate concrete.