Portland cement grout should be kept damp for optimum cure for how many days?

• A. 1 day
• B. 3 days
• C. 5 days
• D. 7 days

Answer: (B)

Cement grout gains most of its early strength through hydration, which requires a steady supply of moisture. If the surface dries out too quickly, the hydration reaction slows or halts, causing shrinkage cracks and weaker bonding to the tiles. Keeping the grout damp during the critical early curing period lets hydration continue and reduces moisture loss, so the grout develops strength properly.

Three days is the commonly recommended duration for damp curing of Portland cement grout. During this time, maintain an even level of moisture on the surface. After about three days, the grout has achieved most of its early strength, and curing continues more slowly, but the key window for optimal cure is around three days.