Mechanical and freezing cycles properties of geopolymer concrete with recycled aggregate

Geopolymer concrete as a green concrete has attracted great attention among scientists to reduce cement consumption and emissions. This study examines the use of recycled aggregates in geopolymer concrete as a substitute for coarse aggregates. To assess the mechanical performance, compressive strength, tensile strength, and flexural strength were measured for 20 mixing designs and their relationships with suitable convergence were obtained. The scanning electron microscope (SEM) images taken from the samples made with the highest and lowest resistance showed that the formation of hardened geopolymer gel depends on the concentration of chemical solutions. The results of the freezing and thawing cycle and mass loss of samples showed that the compressive strength of the geopolymer concrete had not decreased significantly and had a good durability in these conditions.