CSA-treated sand for geotechnical application: Microstructure analysis and rapid strength development

Abstract

This paper studies the effectiveness of calcium sulfoaluminate (CSA), which has a much lower carbon footprint than conventional ordinary portland cement (OPC), in geotechnical applications which use high water:cement ratios. Unconfined compressive strength is used to compare OPC and CSA treated sand. Apart from its ecofriendly characteristics, CSA-treated sand has significantly high initial strength development due to the fast hydration of ye'elimite. Two curing methods are used to simulate wet field and dry field conditions. For both OPC-treated and CSA-treated sand, the samples cured underwater have lower strength than the dry-cured samples. However, the strength reduction due to wet curing is less for CSA than for OPC. In addition, recoverable strength loss is observed in CSA-treated sand subjected to wet curing between 7 and 14 days, which is not observed in dry curing. The effect of water content on the strength of cemented sand is presented. The use of CSA would help move toward a sustainable approach to reduce the carbon footprint in geotechnical applications. (C) 2018 American Society of Civil Engineers.