Mechanical and durability performance of mortars with fine recycled concrete aggregates and reactive magnesium oxide as partial cement replacement

Abstract In this paper, mortar specimens were produced using two types of commercially-available reactive MgO as partial cement replacement (10%, 15% and 20%, by weight) and fine recycled concrete aggregate as siliceous sand substitute (50% and 100%, by volume). The specimens were subjected to thermogravimetric, energy dispersive X-ray, differential thermal and powder X-ray diffraction analyses. The mechanical and durability performance of all specimens was evaluated in terms of their flexural and compressive strength, dynamic modulus of elasticity, water absorption by capillary action, carbonation, and shrinkage. The main results indicate an overall decline in mechanical and durability-related performance with the use of both MgO and fine recycled concrete aggregates, but enhanced shrinkage behaviour was observed in all MgO-containing specimens.