Mix-Design Optimization of Self-Compacting Paste Incorporating Powdery Industrial Solid Wastes Based on a Paste Rheological Threshold Theory

Abstract

The effect of powdery industrial solid wastes on the optimal proportion of pastes and self-compacting concrete (SCC) is investigated in this study. There were nine groups of powdery industrial solid wastes designed, including cement, fly ash (FA), limestone powder (LP), granulated blast furnace slag (GBFS), and modified phosphogypsum (MPG). The powder materials have different properties, such as zeta potential, density, and specific surface area. The paste rheological threshold theory was used to calculate the self-compacting paste (SCP) zone and the optimal proportion. To assess the effect of powder properties on the optimal mix proportion, a model was proposed. The linear regression method was used to obtain quantitative relationships between the optimal proportion and powder characteristics, which can benefit in the SCC optimization process. A new powder combination was designed, and the optimal water-to-powder ratio by volume (VW/VP) and the dosage of superplasticizer by mass (SP%) can be calculated using the powder combination’s physical and chemical properties. The search area was narrowed, and the SCP zone was obtained, where a good SCC was achieved, validating the powder effect model’s effectiveness.