Review of Chemical Treatment Effects on Crumb Rubber from Waste Tires in Concrete Properties

Abstract

The disposal of waste tires has increased substantially in recent years due to the global rise in automobile usage. Incorporating crumb rubber into cementitious composites presents a sustainable solution for waste tire management and can improve the dynamic properties of concrete. However, previous studies have consistently reported a marked reduction in the strength of rubberized concrete. Insufficient adhesion between hydrophobic rubber particles and hydrophilic cement paste remains a primary barrier to widespread structural application. This review evaluates chemical treatment strategies designed to modify the crumb rubber surface and enhance the Interfacial Transition Zone (ITZ). The effectiveness of sodium hydroxide (NaOH), acidic and alkaline solutions, oxidation, sulphur compounds, silane treatment, and mortar coating is assessed. Although NaOH treatment is the most frequently documented, recent cement coating modifications show greater promise for strength recovery. Furthermore, there is a significant gap in research concerning the assessment of the dynamic properties of these chemical modifiers. This review establishes a framework for optimizing rubberized concrete for high-performance structural applications