Influence of artificial lightweight aggregate on property modification of unfired brick with low energy super-sulfated cement

Rapid increase in concrete demand for infrastructural construction has been associated with depletion of natural resources, leading the urgent need to utilize manufactured materials substituting natural materials in concrete productions. This study proposes applying cold-bonded low calcium Class F fly ash (FFA) based artificial lightweight aggregate (ALWA) to partially replace natural fine aggregate in an ecological unfired brick with a low energy super-sulfated cement (SSC). To estimate the influence of ALWA on the brick properties, natural fine aggregate (FA) in the reference brick was substituted with ALWA at four different amounts of 25, 50, 75 and 100% by volume. Various properties including unit weight, flowability, dried density, compressive strength, water absorption, and drying shrinkage were investigated. Experimental results showed that ALWA addition as partial replacement of FA at all ratios resulted in the modified bricks with significantly increase in flowability and decreases in both unit weight and dried density. With neglecting minor reduction on compressive strength, the 75% ALWA substituting FA by volume was considered as the optimum value to manufacture the modified unfired bricks with remarkable enhanced performance.