Title:
OPC-CSAB Blends for Durable Rapid Repair Applications
Author(s):
Burris
Publication:
Web Session
Volume:
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
10/17/2021
Abstract:
Calcium Sulfoaluminate belite cements (CSAB) are known for their rapid setting and early strength development, two traits which are desirable for rapid repair applications and other construction processes where early strength generation is important. However, one of the demonstrated challenges associated with CSAB, when used as a 100% replacement of OPC in concrete mixtures, is its chloride penetration rates. Chloride ingress in CSAB cement matrices have been shown in the lab to progress at a order of magnitude greater rate than in OPC concrete, and could lead to rapid corrosion initiation in CSAB concrete placements. Thus, this work attempted to understand the effects of utilizing binary blends of OPC and CSAB cements to optimize properties for both materials for use in rapid repair applications - (accelerated setting time and strength gain for OPC mixtures without use of chloride accelerators, and increased chloride durability for CSA mixtures). Mixtures were created across a spectrum of CSA:OPC ratios to evaluate the ability of binary cement mixtures to ‘dial in’ desired properties in terms of setting times and early strength development, as well as to produce concrete with adequate resistance to chloride penetration. Results showed that CSAB reactions tended to dominate setting and early strength generation, and that CSAB + OPC mixtures generated greater long-term strengths compared to the 100% OPC concrete.