CEMIX FASTCRETE Fast Set Concrete is a user friendly formulation of sand, aggregate, cement, and admixtures. It is prepared in a fully computerized environment, where a high degree of accuracy and consistency is maintained. It is ideal for setting posts, fences, clothes lines, mailboxes and any use where a strength of up to 15MPa is required. Its unique composition enables it to be poured in a hole already filled with the required amount of water and the post. No mixing is required and the initial set time is only 15 minutes.