PVA and Natural Rubber Latex for Sustainable Pavement Materials

The increasing use of recycled and waste-derived materials offers an important pathway toward more sustainable pavement construction. However, the engineering performance of these materials may require modification before they can be effectively used in road applications. A series of previous studies has explored the use of polyvinyl alcohol (PVA) and natural rubber latex (NRL) as polymer modifiers for conventional and recycled materials associated with ground improvement, pavement base and subbase, asphalt concrete, and concrete pavement applications. PVA, a water-soluble polymer with strong film-forming and adhesive characteristics, has shown potential for modifying both soil-based and recycled materials. In high-calcium fly ash geopolymer-stabilized soft Bangkok clay, PVA enhanced matrix development and increased unconfined compressive strength by approximately 40% at the optimum condition. For pavement base and subbase applications, the combination of PVA and cement improved the strength and toughness of recycled concrete aggregate (RCA), with selected cement–PVA–RCA mixtures satisfying road authority strength requirements. PVA was also used in RCA concrete, where an appropriate PVA dosage improved flexural strength and enabled selected mixtures to satisfy requirements for rigid pavement applications. These studies indicate that PVA can enhance bonding and deformation characteristics in cementitious and geopolymer systems containing recycled or alternative materials. NRL, a renewable elastomeric polymer, has been investigated in a wider range of pavement materials. In cement-stabilized soils and pavement base materials, appropriate NRL contents improved tensile strength, resilient response, deformation characteristics, and fatigue resistance. In bottom ash-based geopolymer-stabilized RCA, NRL film formation contributed to improved interaction between RCA particles and the geopolymer matrix. For flexible pavement surfaces, NRL-modified asphalt mixtures showed improvements in tensile strength, resilient modulus, fatigue resistance, and rutting performance, with the response influenced by rubber content and aggregate characteristics. In concrete pavements, suitable NRL contents enhanced flexural strength and flexural fatigue resistance and improved resistance to sulfate-induced deterioration. NRL has also been incorporated with RCA, fly ash, PET, and crumb rubber, extending its application to pavement materials containing recycled and waste-derived constituents. Across these studies, the beneficial effects of PVA and NRL are associated primarily with polymer-film formation, improved particle or matrix bonding, and modification of the deformation response. Their effectiveness nevertheless depends on polymer dosage, binder system, material characteristics, and the targeted engineering property. The accumulated findings highlight the importance of material-specific and performance-based optimization of PVA and NRL in developing sustainable pavement materials that incorporate both conventional and recycled resources.