The role of organic polymer modifiers in cementitious systems towards durable and resilient infrastructures: A systematic review

• Over 370 articles from 1982 to 2022 (40 years) have been systematically reviewed. • Organic polymer modifiers play different roles and functions in cementitious systems. • Physical and chemical polymer–cement interactions modify hydration kinetics and physico-mechanical behaviours. • Self-healing, waterproofing and corrosion-inhibiting effects of polymers prolong the service life of concrete. • Polymer films and particles refine the microstructure and pore structure of concrete. With the deterioration and ageing of concrete structures, repair and rehabilitation have emerged as one of the most critical activities associated with high maintenance costs. One of the most promising resolutions for improving the long-term cost-effectiveness and serviceability of cementitious materials is the incorporation of organic polymer modifiers. Hence, this paper aims to review the pivotal role of polymers and elucidate their mechanisms in cementitious systems. Overall, organic polymers have multi-functions, which can simultaneously act as rheology regulators, setting and hydration modifiers, self-healing agents, reinforcing members and microcrack stoppers, corrosion inhibitors, electrical insulators, energy absorbers and waterproofing membranes. The physical adsorption, chemical interaction among colloidal particles, types of surface charge, particle size and pH value strongly influence the rheological characteristics and hydration of the cement matrices. While the structural network of polymer chains triggers different self-healing actions and reinforcing mechanisms to strengthen the polymer-cement bonding. The formation of polymer films across matrices and pores hinders ion diffusion and transport, thereby enhancing corrosion resistance, electrical insulation and waterproofing. Viscoelasticity of polymer layers also contributes to the energy absorption against shock and vibration. The morphology of cement hydration tends to be slightly modified due to the interaction between polymer particles and phases. Meanwhile, pore structure varies depending upon the dual effect of air entrainment and pore refinement. In practice, polymer-concrete composites are opted for repairing purposes or concrete structures in aggressive environments. Recently, 3D printable polymer-modified concrete has attracted many studies due to its high interlayer bond strength compared to traditional 3DP concrete. Despite high performance and durability, the addition of polymers in concrete has faced several challenges, including but not limited to mixing, curing regime, delamination, photo-oxidation, flammability, toxicity and high initial cost. Nonetheless, its drawbacks can be addressed by adopting advanced technologies and necessitating future research and development.