Title: Using Drinking Water Treatment Waste as a Low-Cost Internal Curing Agent for Concrete

Author(s): Qiwei Cao Nowasell and John T. Kevern

Publication: Materials Journal

Volume: 112

Issue: 1

Appears on pages(s): 69-78

Keywords: compressive strength; curing agent; degree of hydration; internal curing; scanning electron microscopy; shrinkage

DOI: 10.14359/51686980

Date: 1/1/2015

Abstract:
This paper presents results from a preliminary study that investigated the potential of using drinking water treatment waste sludge as an internal curing agent for concrete. The concept consists of using the high water content, primarily calcium carbonate material, as a concrete admixture. Two other commonly used internal curing agents—prewetted lightweight fine aggregate and a superabsorbent polymer—were investigated as a comparison. Cement mortars were tested for compressive strength, degree of hydration, and shrinkage. Micrographs of mortars containing the three different internal curing agents were compared visually to evaluate the distribution of internal curing agents and relative hydration. Results show that drinking water treatment waste is an effective internal curing agent, improving cement hydration, compressive strength, and mitigating autogenous shrinkage.