Builders Cement is a blended cement that fully complies with the requirements for Type GB cement described in AS3972 – Portland and blended cements. This product nominally contains 25% fly ash. Combine cement, clean aggregate and sand in correct proportion in a non-porous vessel. Large jobs require a concrete mixer. Add drinkable water gradually and mix thoroughly. Use enough water to make a workable mix. Excess water ruins good concrete. Use the product immediately after mixing. Keep job moist for 7 days for the best results.