Influence of NaOH treatment of rubber aggregates on the durability properties of rubberized mortars

The work presented in this paper aims to study the durability of mortars, in which part of the sand has been replaced with rubber aggregates from used tires and have undergone a surface treatment with a sodium hydroxide solution (NaOH). The substitution rates studied are 10%, 17.5%, and 25%. The results are compared with ordinary mortar and mortars with untreated rubber aggregates while samples with the same substitution rates were used. To do this, the following properties have been studied: compressive strength, flexural tensile strength, water absorption by capillarity, water absorption by total immersion, water-accessible porosity, water permeability, and resistance to the chemical degradation by sulfuric acid H₂SO₄.

The results obtained show that the treatment of rubber aggregates by the solution method (NaOH) presented a considerable improvement in mechanical performance (increase in compressive strength and flexural tensile strength) and better durability compared to reference mortar and mortar with untreated rubber granulate.