Stiffness of ramming mixes and refractory mortar joints – effects of temperature and installation practice

Abstract

In refractory linings, the behaviour of ramming and mortar joints is essential for the performance of the whole structure. The compressive stiffness of commercially available ramming mixes and mortars is discussed in this paper. Effects of temperature, density and the joint thickness are analysed. The data are obtained using uni-axial tests with lateral constraints, maximally representative for the service conditions. The results indicate that above 700°C for the ramming and in the range 300-1000°C for the mortar, the joints are to develop stiffness of the same order of magnitude as the surrounding refractories. Viscosity effects are expected below 50°C and above 1000°C for ramming and mortar, respectively. The deviation from the specified density and the joint thickness is to affect the joint stiffness in the whole service temperature range.