High alumina cement is also called aluminate cement, commonly known as bauxite cement. The raw materials are bauxite and lime, which are prepared in a certain proportion and then calcined and ground to make a hydraulic cementitious material. It can be used as a binder for refractory castables.
1. High alumina cement has high heat of hydration. It cannot be used in large-area concrete projects and wet and high-temperature projects. It is most suitable for use in an environment of 5-35 degrees. Adding a certain proportion of high temperature refractory cement to the castable can make the castable set fast and have strong compactness during construction.
2. High alumina refractory cement has strong resistance to sulfate erosion. The cement stone structure of high alumina cement is dense, the main component is low calcium aluminate, and the calcium oxide content is very small. It is more suitable for applications that require high sulfate resistance.
3. High alumina refractory cement has good heat resistance. Because solid phase reaction occurs at high temperature and sintering bonding replaces hydration bonding, high alumina cement will always maintain a solid phase state in a high temperature environment, and the strength of the cement will not change.
4. The requirements for the use of high alumina cement are relatively harsh. The early strength of high alumina cement increases rapidly, and it is suitable for use in emergency rescue projects or projects with high early strength requirements. The late strength of high alumina cement will decrease, especially in a humid and hot environment higher than 30℃, the strength of high alumina cement will drop even more fast and more obviously. In severe cases, it will cause damage to the castable structure, so be cautious when using high alumina cement in structural engineering. High alumina cement is weak in alkali resistance. High alumina cement will cause corrosion when it comes into contact with alkaline solution, and it will also cause corrosion when a small amount of alkaline compound is contained in the concrete aggregate. Therefore, it is said that high alumina cement cannot be used in projects that contact alkaline solution.
