ISTRA 40 is a normal setting, rapid hardening Cal-cium Aluminate Cement (CAC) with high early strength. It differs substantially from the usual calci-um silicate cements (Portland cements) in its manufacturing process, chemical composition and rapid strength gain. ISTRA 40 is composed of calcium aluminates with the following characteristics: high early strength, refractoriness, high abrasion resistance, resistance to biogenic sulphuric acid corrosion (BSAC.