Development of Sustainable High-Strength Self-Consolidating Concrete Utilising Fly Ash, Shale Ash and Microsilica

Abstract

With high flowability and passing ability, self-consolidating concrete (SCC) does not require compaction during casting and can improve constructability. The favourable properties of SCC have enabled its widespread adoption in many parts of the world. However, there are two major issues associated with the SCC mixes commonly used in practice. First, the cement content is usually at the high side. Since the production of cement involves calcination at high temperature and is an energy-intensive process, the high cement content imparts high embodied energy and carbon footprint to the SCC mixes. Besides, the exothermic reaction of cement hydration would cause high heat generation and early thermal cracking problem that would impair structural integrity and necessitate repair. Second, the strength is usually limited to around grade 60, which is considered as medium strength in nowadays achievable norm. With a view to develop sustainable high-strength self-consolidating concrete (HS-SCC), experimental research utilising fly ash (FA), shale ash (SA), and microsilica (MS) in the production of SCC has been conducted, as reported herein.

Cement Equivalence of Metakaolin for Workability, Cohesiveness, Strength and Sorptivity of Concrete

“…This is echoed by the finding that the CEF values for SI are always larger than those for flow. As both cohesiveness and flowability are needed for self-consolidating concrete [65][66][67], such increase in cohesiveness at the same flowability, i.e. improvement in concurrent cohesiveness-flowability performance, due to MK addition, demonstrates that MK is a useful SCM for producing self-consolidating concrete.…”