Cement base grout can be worked on in how many days and reaches full compressive strength after how many weeks?

The choice indicating that cement base grout can be worked on after 7 days and reaches full compressive strength after 4 weeks is correct.

Cement-based grouts typically develop a significant portion of their strength within the first week. After 7 days, the grout has hardened enough to allow for further construction activities to resume safely. This timeframe is important for contractors as it helps schedule subsequent work without delaying the overall project timeline.

Full compressive strength of cement-based grout is generally achieved around 28 days; however, in some guidelines and practical scenarios, it is often acceptable to consider it fully operational after 4 weeks. It is crucial for millwrights and construction professionals to understand these timeframes because they impact the planning and execution of projects, particularly when heavy machinery or other loads will be placed on the grouted materials.