Impacts of trace additives and early-stage curing conditions on the shrinkage cracking resistance of blast-furnace slag cement concrete

Abstract

Medium volume blast furnace slag concrete has been highly expected to reduce carbon dioxide emission in concrete production, while it was found that this concrete was prone to shrinkage cracking specifically under hot summer climates. To improve this negative performance, this study focused on the utilization of trace additives and water curing. The trace additives were gypsum and calcium carbonate, with which binder is called low shrinkage BFS. Furthermore, to reduce prominent autogenous shrinkage, initial water curing was investigated. As a result, combination of low shrinkage BFS and water curing was found to significantly strengthen shrinkage cracking resistance, which was expressed by cracking age resulted in restrained shrinkage cracking tests. Furthermore, curing experiment showed that water curing may be substituted by water covered curing on element surface in construction site as a simple and economical measure to supply water to concrete at initial stage of hardening.