The curing times effect on the strength of ground granulated blast furnace slag (GGBFS) mortar

Abstract

This research aims to study the effects of setting times and soundness of the GGBFS cement for various fineness of ground granulated blast furnace slag (GGBFS) as partial replacement ordinary Portland cement (OPC) at 20 wt%, 40 wt% and 50 wt%, on the compressive and flexural strength of GGBFS mortar. A total of 54 test samples and 9 controlled samples of prisms were cast and cured for 7, 28 and 90 days before compressive and flexural strength test. However, the setting times and the soundness test results of GGBFS cement and controlled OPC were investigated. The results showed that GGBFS cement with higher Blaine’s fineness with 40 wt% replacement had the highest compressive strengths of 57.29 MPa and 69.70 MPa at 28 and 90 days of curing duration respectively. Moreover, outperformed OPC with compressive strengths of 55.67 MPa and 61.49 MPa at 28 and 90 days of curing duration, respectively. Setting times decreased with a higher fineness of GGBFS cement, but increased with greater percentages of GGBFS cement, while the average expansion of soundness test is within acceptable limits. Therefore, it can be concluded from this study that curing duration increases the strength of mortar and GGBFS cement is useful for partial replacement of OPC.