Remediation and Air Void Stability of Hauled Self-Consolidating Concrete

Abstract

In the production of self-consolidating concrete (SCC), long hauling times are often necessary for transportation to the job site. During such hauling time, highly fluid SCC can lose a significant amount of slump flow, necessitating the mixtures to be remediated. Consequently, hauling and remediation can have a detrimental effect on the air void size and spacing, which are necessary characteristics for guaranteeing adequate frost durability in the hardened concrete. The purpose of this investigation was to determine the effects of two forms of remediation, overdosing and retempering, on the air void characteristics of SCC. Three slump flows of 559, 635, and 711 mm and eight hauling times from 20 to 90 min were studied. The required admixture dosage for each remediation technique depended on the target slump flow and hauling time duration. Hauling time and remediation caused the air content to increase and air void characteristics to improve from their initial state, although they typically were inferior to the nonremediated mixtures. Both forms of remediation exhibited similar trends in air void characteristics with hauling time.