Need. After sand, flaky and cement enter the site, testing engineer must be notified in advance to take samples for inspection. You can't start using it until it is qualified. The construction team shall prepare the mold trial and temporary curing pool, and the test pieces shall be randomly selected by the tester. However, before the construction starts, the construction team must inform the testers, and the inspection report witnessed by the supervisor should not be less than 20%. The specimen shall be kept and maintained by members of the construction team at the construction site.