Characterisation of mortarless refractory masonry joints under elevated temperatures

•Dry joint closure in alumina-spinel refractory masonry at elevated temperatures.•Non-linear joint closure behaviour due to the distribution of surface asperities.•Joint closure behaviour at different temperatures is related to thermal expansion and material stiffness.•Validation of various analytical models to represent non-linear joint closure behaviour.•Numerical analysis to evaluate joint closure behaviour in mortarless refractory masonry.