Optimization of low-cement high-temperature resistant composite mixtures

Cement-based composites have a very broad field of applications but their composition has to be designed with care to meet the desired functional properties. High-temperature resistant mixtures can be stated as a characteristic example in that respect. The standard calcium silicate binder should be replaced usually by high alumina cements which can be supplemented by waste materials or byproducts within the global environmental protection efforts. To reach the optimal properties and composition, advanced optimization techniques are supposed to be used rather than empirical approaches. This paper presents an application of downhill simplex method to optimize the composition of a binder based on calcium alumina cement and supplemented by ceramic powder, super reactive alumina and boehmite powder. The optimization procedure results in a 7% improvement of compressive strength, which reaches ∼117 MPa. Due to the high temperature resistant nature of all substances used (chamotte and corundum as fillers), the proposed mixture is supposed to resist increased temperatures up to 1400 °C.