Influence of curing conditions on the mechanical and physical properties of chemically-activated phosphorous slag cement

• High phosphorous slag content cement was chemically and thermally activated.
• Strength development of this cement was studied at various curing conditions.
• Curing at temperatures higher than 85 °C results in lower compressive strength.

In this paper, the influence of curing time and temperature on the compressive strength development of chemically-activated high phosphorous slag content cement composed of phosphorous slag (80 wt.%), Portland cement (14 wt.%), and a compound chemical activator consisting of sodium sulphate and anhydrite (6 wt.%) is investigated. For this purpose, mortar specimens were prepared and cured in lime-saturated water at different temperatures of 25, 45, 65, 85, and 100 °C in an oven and at temperatures of 165 and 200 °C in autoclave. Results showed that the ultimate compressive strength decreases at curing temperatures higher than 45 °C. Investigations by XRD and FTIR show that curing at temperatures higher than 45 °C results in the formation of α-C2SH.

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