Effect of SCM and superplasticizer on excessive paste thickness and properties of concrete

Abstract

The optimum mix design considering fresh and hardened mechanical properties is of great significance for the quality of construction materials. This study mainly examines the influence of excessive paste thickness based on the variation of supplementary cementitious materials (SCMs) and superplasticizer content on the mechanical properties of high-performance concrete (HPC). The test results exhibited the significance of excessive paste thickness on slump flowability and flow retention even without a superplasticizer. The yield stress of HPC was mainly influenced by the presence of a superplasticizer, however, plastic viscosity was primarily dependent on the excessive paste thickness. The test results exhibited that the presence of fly ash slightly improves the rheological properties of HPC, however, its trend depends on the presence of a superplasticizer. The excessive paste thickness has a positive impact on the strength development of HPC up to an optimal point indicating the significance of paste thickness as well as superplasticizer. A slight reduction in compressive strength was observed with the replacement of cement with fly ash, however, a positive impact based on the presence of slag was observed. No significant effect of excessive paste thickness on various environmental factors such as abrasion, chloride penetration, and carbonation of HPC was examined.