Concrete is a building material that is made from a mixture of cement, water, and aggregate. Once it is mixed, it is poured into moulds or forms where it will harden. The time it takes for concrete to be fully set depends on a number of factors, including the type of cement used, the ratio of water to cement, the temperature and humidity levels, and the size and shape of the mould. In general, concrete takes 24 to 48 hours to fully set. However, in some cases, it can take up to 28 days for the concrete to reach its full strength. Therefore, it is important to consult with a professional before starting any concrete project.