Behavior of the use of fine recycled concrete aggregates on rheological parameters and hardened mortar properties

Abstract

The depletion of natural sand and the large amount of demolition waste that exists across the world are realizing the potential benefits of using this abundant waste to create recycled fine aggregates for use in the production of masonry mortars. This research aims to analyze the mechanical performance of mortar with recycled aggregates from old concrete, natural sand (NS) is partially substituted with fine recycled concrete aggregates (FRCA) and a quantity of superplasticizer has been added to keep the same spreading. The experimental study focused on different substitution rates by volume (0%, 25%, 50%, 75% and 100%) for recycled sand. Tests in the fresh state of the mortar such as spreading, yield stress and plastic viscosity will be carried out. In order to evaluate the mechanical performance of the recycled mortar, tests of compressive strength and flexural strength will be carried out. As well as the effect of the use of these aggregates on durability such as shrinkage and sorptivity. The results found show that recycled sand can be an alternative to natural sand, despite its detrimental effects on the durability properties of the mortar. These effects can be neglected given its contribution to the economic and environmental aspect. Adequate relationships have been established to predict rheological parameters, mechanical strengths and durability performances as a function of test parameters with high correlation coefficient and low root mean square error.