Strength properties of self-compacting mortar mixed with GGBFS

Abstract

Self-compacting cement grout (SCCG) is one of the e conomical and an effective material used for repairing structural cracks. However, in terms of raw material cost, SCCG is higher than for conventional concrete due to the high cement volume s at relatively low water-binder ratios to achieve satisfactory combinations of high fluidity and stability. It is expected that ground granulated blast furnace slag (GGBFS) can be used a s an alternative material to replace high volume of cement in preparing self-compacting repair mortar (SCRM). In this study, the effects of GGBFS content on both fresh and hardened properties of SCRM were investigated. The influence of different curing conditions on lon g term compressive strength was also studied. In addition, the microstructure of some mi xes at the age of 6 months was also observed by using scanning electron microscope. The results show that the workability and final bleeding value of fresh SCRM decreased with the inc rease in GGBFS content. At early ages, the compressive strength rate of SCRM incorporating GGBFS was lower but it increased with time and became more pronounced at 30% to 50% repla cement level. Thus, the maximum limit of GGBFS replacement is suggested to be controlled at 50% to make the most excellent development in long-term compressive strength. As f or curing condition, specimens stored in water showed higher gain in long-term strength than those samples exposed to air and natural weather weathering conditions.