Prolonging the Initial Setting Time of Cement using Gypsum and Recycled Marble Powder for Hot Desert Climates

This study evaluated a practical, sustainable mineral intervention to overcome premature cement setting in hot desert environments. The key findings are summarized below: Desert Heat Impact: Temperatures above 35* accelerate cement hydration, cutting setting time to under 45 minutes. Gypsum Function: Adding 3%–4% gypsum provides soluble sulfate to prevent flash setting. Marble Powder Function: Waste Marble Powder (WMP) fills pore voids and forms monocarboaluminate to lower heat output.  Mix M1 (Control — 100% OPC): Initial setting time of 68 minutes due to unretarded clinker hydration.  Mix M2 (3% Gypsum / 5% WMP): Extended setting time to 92 minutes, but formed a weak, porous structure. Mix M3 (3% Gypsum / 7% WMP): Optimal blend — initial setting time of 88 minutes with the highest structural strength. Mix M_4 (4% Gypsum / 8% WMP): Longest setting time at 120 minutes, but suffered from water bleeding and poor matrix compatibility. Practical Outcome: The M3 blend (3% Gypsum + 7% WMP) restores placement open time while lowering cement carbon emissions by 12%–15%

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