Before pressure and leakage tests are done for a new pipe installation, allow at least ______ days for the concrete used for thrust blocks to cure.

• A. 1 Day
• B. 3 Days
• C. 5 Days
• D. 7 Days

Answer: (C)

Allowing the thrust-block concrete to cure before applying pressure tests ensures the block has developed enough strength to resist the hydraulic forces once the system is pressurized. Concrete gains compressive strength as it cures, and a five-day minimum gives sufficient strength to hold the block in place and prevent movement or cracking during testing. Shorter curing times, like one or three days, risk insufficient strength and potential leaks or block failure when pressure is applied. Seven days is longer than typically required under standard conditions, unless special climate or mix factors demand it. Therefore, the recommended minimum curing time is five days.