冻融循环对硅烷改性ECC力学与吸水性能的影响OA

This study comprehensively investigated the influence patterns and mechanisms of internally incorporated silane types on the mechanical properties and water absorption properties of engineered cementitious composites(ECC)using multiple material testing techniques.It analyzed the evolution patterns and microscopic mechanisms of mechanical and water absorption properties for both unmodified ECC and isooctyl triethoxy silane IOTS modified ECC after freeze-thaw cycles.The results show that:except for γ-methacryloxy propyl trimethoxy silane(KH570),neither IOTS nor N-(β-aminoethyl)-γ-aminopropyl trimethoxy silane(KH792)causes a significant negative impact on the mechanical properties of ECC.Both KH570 and KH792 markedly delay the hydration heat release of the cementitious materials.The IOTS modified ECC exhibited the best hydrophobicity,maintaining its hydrophobic characteristics even after severe freeze-thaw damage.After freeze-thaw cycles,the compressive strength deterioration rate of IOTS-modified specimens is higher than that of unmodified specimens,but their flexural strength remains higher.As the number of freeze-thaw cycles increases,the relationship between the water absorption mass per unit area and the square root of time shifts from linear to bilinear for both types of specimens,and the duration of the initial linear stage shortens as the number of freeze-thaw cycles increases.The research findings provide a theoretical basis for the hydrophobic design of ECC and its application and durability evaluation in freeze-thaw environments.