Effects of hardening accelerators on the performance of self-compacting mortars designed for rapid repair purposes

Today, self-compacting mortars are mostly preferred for patch repair purposes due to their application easiness and labour saving advantages. However, the speed of hardening in case of conventional self-compacting mortars is not appropriate for many rapid repair purposes. In this study, it was aimed to develop a repair mortar that was initially self-compactable at fresh state and gain high strength at early hours of hydration. The main ingredients of this mortar were calcium aluminate cement (CAC), quartz aggregate and polycarboxylate based superplasticizer. In order to provide high early strength three accelerators (sodium aluminate, calcium chloride and lithium carbonate) were employed at varying dosages. From these accelerators, lithium carbonate was found as the most appropriate. Optimum dosages of lithium carbonate were proposed which brought a self-compactable and high early strength mortar mixture at the same time. However, it should be noted that as a general tendency, any attempt that improved the early strength, reduced the later age strength of repair mortars.