Preventing crack propagation for self-healing potential in PVA-modified CSH composites

J Jia and A Zaoui and W Sekkal, CONSTRUCTION AND BUILDING MATERIALS, 491, 142771 (2025).

DOI: 10.1016/j.conbuildmat.2025.142771

Concrete is present in vast quantities in the world's infrastructure and continues to be used at an enormous rate. Cracks of concrete often lead to a loss of serviceability. The study employed molecular dynamics simulations with reactive force field to investigate the structure, interfacial bonding, and mechanical response of calcium silicate hydrate (CSH) systems modified with 1-5 % content polyvinyl alcohol (PVA), carbon nanotubes (CNT), and hydroxyl-functionalized CNTs (CNT-OH) at different positions (interlayer and crack). In-crack PVA builds dense C-O-Si bridges, quadruples adhesion energy (-8.0 vs-2.1 x 10 3 kcal mol-1) and lifts peak tensile stress by 31 %, while also boosting Young's modulus in the strong direction by 26 %. Gains rise non-linearly with dosage and saturate at 5 %, 1 and 3 % improve strength by only 1 % and 7 %, respectively. CNTs create fewer interfacial bonds and disturb the Ca-O network. This study aims to provide systematic guidance for the improvement of cementitious composite construction materials.

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