Early-strength mechanisms, carbon sequestration, and phytocompatibility of ecological porous concrete synergistically modified with triethanolamine and nano-silica: Hydration kinetics and microstructural mechanisms

To address the specific demands for early-strength materials in ecological slope emergency restoration projects and ecological slope construction in cold regions, this study has developed Ecological Porous Concrete (EPC) with low-alkali characteristics and enhanced early-strength advantages through a synergistic mechanism of alkalinity regulation and strength enhancement. This provides new material support for advancing the ecological restoration technology system within the context of carbon neutrality. In this study, we systematically investigated the influences of triethanolamine (TEA) and nano-silica (NS) on the mechanical properties and CO₂ absorption capacity of EPC cementitious materials. The results indicate that the incorporation of TEA and NS effectively mitigates the issue of reduced early strength in EPC caused by oxalic acid, leading to a significant improvement of 33.3 % in the early mechanical properties. Furthermore, the addition of TEA and NS promotes crystal nucleation and growth during the hydration reaction of EPC cementitious materials, facilitating the transition from the nucleation and growth (NG) process to the impingement (I) process, and enhances the CO₂ sequestration capacity of the EPC cementitious materials. Planting tests demonstrate that the early-strength EPC exhibits excellent vegetation performance, fulfilling the practical needs of the project. These research findings offer robust technical support for accelerating the construction speed of EPC and ensuring project quality. They are of considerable significance in promoting the industrialized application of EPC in green building and ecological restoration fields, particularly in cold region engineering and emergency ecological slope restoration projects.