Performance evaluation of regenerated clinker from completely recyclable mortar

Abstract This study aims to characterize the performance of recycled clinker prepared from more sustainable concrete that can preserve natural resources. A completely recyclable mortar (CRM) was designed with a composition similar to that of the raw cement materials. Then, recycled cement generated from CRM was used to prepare another CRM and further recycled. The XRD patterns, free calcium oxide content, and mechanical strength of the recycled clinker after each cycle were studied. The results showed that as the number of cycles increased, the strength and hydration activity of the recycled cement clinker gradually decreased. Mineralogical composition analysis showed the weakening of the C3S diffraction peak and decrease in C3S content as well as strengthening of the C2S diffraction peak and increase in C2S content with an increase in cycle number. The degradation of the recycled clinker performance may be attributed to the presence of unhydrated cement particles in the heat-cured mortar. Although the hydration activity of the recycled cement clinker decreased, its carbonization strength increased significantly, which could be attributed to its high C2S content.