Influence of structural and phase conversions on the thermomechanical properties of chamotte concrete based on high-alumina cement

Conclusions The dehydration of the calcium hydroaluminates and aluminum hydrates when the concrete is heated causes the binder to lose strength and results in the formation of a porous structure.The structure of the cement block depends on the fineness of the cement. During heating at 1100°C, two processes develop in the binder, viz., solid-phase diffusion sintering accompanied by shrinkage, and coalescence of the pores.The reaction of the cement with the chamotte results in the formation of low-temperature minerals in the form of calcium aluminosilicates, the consequence being that liquid-phase sintering continues accompanied by considerable shrinkage.Above 1200°C and especially above 1300°C a large amount of liquid phase is formed in the concrete and dissolves the crystalline minerals (calcium aluminosilicates, mullite, cristobalite, and corundum).The peak temperature at which the chamotte concrete based on high-alumina cement can be used is 1350°C.Translated from Ogneupory, No. 1, pp. 52–57, January, 1977.