Properties of cement-based bricks with oyster-shells ash

The large amounts of abandoned oyster-shells in ostrea-culture have led to serious environmental problems and health hazards. This paper presents a parametric experimental study on the recycling of calcined oyster-shells ash (OS) to replace lime in the production of unfired fly ash bricks (UFB). Experiments were conducted with five different replacement levels of OS (between 0% and 20%) to study the effect on mechanical strength and freeze-thaw resistance. In addition, this study investigates the effect of wet-dry cycles on the shrinkage, water absorption and strength of UFB samples. According to the test results, the bricks incorporating OS and lime achieved 28-day strength and durability within grade M15 according to GB/T2542-2012 (Chinese Standard). Moreover, the wet-dry cycles within the investigated limits in this study showed positive effect on mechanical properties, indicating that the bricks are usable in both wet and dry environmental conditions. The present investigation demonstrates a potential application of waste OS that can enhance the sustainable of society by reducing environmental pollution by converting hazardous waste into useful construction material.