Effects of aluminate rich slag on compressive strength, drying shrinkage and microstructure of blast furnace slag cement

Abstract

Aluminate rich steel slag (ARS) is a by-product of the steelmaking process. ARS contains high contents of Al2O3 and CaO and is mainly composed of C(12)A(7) and C(3)A. This work investigated the effects of ARS and gypsum on the mechanical and chemical properties of blast furnace slag cement. The compressive strength, drying shrinkage, hydration and microstructure characteristics of blast furnace slag cement were investigated based on the addition of different percentages of ARS and gypsum. The results showed that a quaternary binder of OPC-GGBFS-ARS-Gypsum has a beneficial effect on the compressive strength and drying shrinkage. The ettringite formed in the OPC-GGBFS-Gypsum binder were like sharp needles while the ettringite formed in the OPC-GGBFS-ARS-Gypsum binder were like thick needles. Because of such ettringite formation differences, the compressive strength and drying shrinkage of the quaternary binder was better than that of the ternary binder. (C) 2017 Elsevier Ltd. All rights reserved.