Mechanical properties of low‐carbon cementitious sand based on olivine sand synergized with multi‐source industrial solid waste

Abstract Over the past two decades, the global construction industry has experienced a period of significant expansion, and its development process has been accompanied by significant carbon dioxide emission problems. Olivine is a widely distributed alkaline mineral with excellent carbon sequestration performance, which can permanently fix carbon dioxide. Therefore, in this paper, olive sand and multi‐source industrial solid waste are used in cement‐based composites to fix the carbon in building materials. This provides an innovative method for reducing carbon emissions in the construction industry. At present, there are relatively few studies on the mechanical properties of olive sand combined with industrial solid waste as cementitious materials. This study investigated the partial substitution of cement by fly ash and steel slag, as well as the substitution levels of olive sand (0%, 25%, 50%, 75%, 100%). The mechanical properties of fly ash—steel slag—olivine low‐carbon cement mortar (FGL) before and after carbon sequestration were studied. The changes in mechanical properties and brittle failure mechanisms of materials before and after carbon fixation during compression and bending tests were analyzed by using digital image correlation (DIC) technology. DIC analysis revealed that carbonation‐induced densification delayed crack initiation and increased strain localization resistance. The results show that after carbon sequestration treatment, its flexural strength and compressive strength increase by at least 2.2%–23.7%, respectively. Before and after carbon sequestration, the strength increases with the increase of olive sand content. The above‐mentioned research will contribute to the development of new low‐carbon concrete.