Effect of Mix Design on Fresh Self-Consolidating Concrete and Inferences on Formwork Pressure

Abstract

The use of self-consolidating concrete (SCC) has become more prevalent due to its economic and technological advantages over other types of concrete. Nevertheless, issues relating to casting and placement hinder its widespread use. One of the primary concerns of using SCC is related to its high formwork pressure, which affects any type of structural element, whether it is precast or cast on site. This study aimed to make correlations between different parameters obtained through slump flow and shear rheological tests in order to determine what the implication would be on the evolution of formwork pressure for five typical precast SCC mixes. The parameters were slump flow diameter, spreading rate, yield stress, plastic viscosity, and rate of structural rebuilding (stress relaxation). In addition, the advantages, from the point of view of cost and safety, of incorporating nanoclays and viscosity-modifying admixtures in SCC to reduce initial pressure and increase rate of pressure drop to optimize the formwork design were demonstrated.