Properties of super-thin layer mortar with recycled brick fines for sintered perforated block masonry

A super-thin layer of mortar with recycled brick fines (RBF) for sintered perforated block masonry was prepared. Six mortar mixtures were designed with different replacement ratios of RBF from 0 % to 50 %. The physical and mechanical properties were experimentally investigated, including compressive strength, tensile bond strength, freezethaw resistance, density, water preservation and thermal conductivity. When the RBF replacement ratio increased, the compressive strength of the mortar at 7 days, 28 days and 56 days showed an upward trend and reached its maximum value when the RBF replacement ratio was 40 %. However, when the replacement ratio of RBF was below 30 %, the tensile bond strength increased. With an increase in the RBF replacement ratio, the mass and strength loss of the mortar increased, and the thermal conductivity decreased. Furthermore, the SEM analysis results show that with an increase in the RBF replacement ratio, the microstructural characteristics of the mortar were more porous. The mechanical behavior of sintered perforated block masonry with the super-thin layer mortar was tested. The results indicated that the compressive and shear strengths of masonry were influenced by the daubing technology of super-thin layer mortar. The compressive strength and shear strength of masonry when using super-thin layer mortar daubed on both sides could reach 84% and 89%, respectively, of those with special high-cost mortar.