Effects of Impure Water Sources on the Early-Age Properties of Calcium Sulfoaluminate (CSA) Cement

Abstract

One of the benefits of calcium sulfoaluminate (CSA) cements is that these materials gain strength rapidly, and strength development is often measured in hours instead of days. This property makes these materials desirable for use in temporary, nonreinforced repairs of roadways, airfields, and navigable locks. The rapid repair of these infrastructure elements is critical to transporting supplies into regions devastated by disaster. In these austere environments, potable water may not be available in sufficient quantities to make vital repairs, and the use of impure water in the production of CSA cement–based concrete would be advantageous. However, the hydration products formed by CSA cement are significantly different from those formed by portland cement and may react differently to alkalis, chlorides, sulfates, and other contaminates that these impure water sources may contain. This article investigates the impact of calcium, sodium, potassium, and magnesium chloride and calcium, sodium, and magnesium sulfate on the early-age unconfined compressive strength development of commercially available CSA cement–based concrete. Of these salts, calcium chloride had the greatest effect on early-age concrete properties, retarding unconfined compressive strength development. The strength results obtained from CSA cement–based concrete mixed with these saline solutions are compared with those obtained from potential real-world sources of mixing water, including seawater and greywater.

Effects of impure water sources on early-age properties of calcium sulfoaluminate cements for rapid airfield damage recovery

“…The laboratory study effort was broadly focused on identifying the factors of primary influence on early-age properties and is documented in Chapters 3 and 4. The laboratory study was utilized for an MSCE degree thesis (Long 2019), and a portion of the laboratory data has also been published in Long et al (2019). The field demonstration addressed the specific application of CSA cement to rapid airfield damage recovery (RADR) scenarios and is documented in Chapter 5.…”

Synergetic–Complementary Use of Industrial Solid Wastes to Prepare High-Performance Rapid Repair Mortar

“…Calcium sulfoaluminate (CSA) cement features high early strength, low permeability, rapid setting, and slight expansion properties, which are primarily attributed to the rapid crystallization of ettringite (3CaO Al 2 O 3 3CaSO 4 32H 2 O), produced by the hydration of the key mineral, ye'elimite (3CaO 3Al 2 O 3 CaSO 4 ) (Telesca et al, 2014;Du et al, 2021). Researchers have found that CSA cement is very suitable as the cementing material for RRM preparation (Zhang J. et al, 2018;Long et al, 2019;Yeung et al, 2019). Moffatt and Thomas (2017) prepared RRM by blending 30% CSA cement with 70% OPC as the cementing material, and achieved a compressive strength of 22 MPa at 3 h. Shi et al (2021) also prepared RRM using CSA cement, and the flexural and compressive strengths at 1 day reached ∼7 and ∼36 MPa.…”