Influence of initial steam curing and different types of mineral additives on mechanical and durability properties of self-compacting concrete

Some projects have to be done in a short period of time, especially in urban regions. Since molds have to be demolded as soon as possible, the rate of concrete element production plays an important role in the progress of the whole project. Therefore, initial heat or steam curing at atmospheric pressure is highly needed to achieve a considerable initial compressive strength so that molds can be used for another casting. On the other hand, reduction in the usage of Portland cement clinker, the production of which is highly energy consuming and CO2 emissive, can be achieved by using mineral additives. In this study, the effect of initial steam curing and different types of mineral additives (Metakolin, Pomis, and Trass) on mechanical and durability characteristics of self-compacting concrete (SCC) was investigated and evaluated by various test methods. Concrete specimens were exposed to six different steam curing regimens after casting, namely two different temperatures (60, and 70 °C), and three total steam curing durations (16, 18, 20 h). Results of capillary absorption, surface electrical resistivity, and Rapid chloride penetration test (RCPT) as durability tests, and compressive strength for mechanical properties showed that exposing specimens to higher temperature could significantly improve compressive strength by promoting hydration; however, regarding scanning electron microscope (SEM) analysis it has several adverse effects on durability.