Durability of Modified Asphalt-Based Grouting Material for Post-Tensioned Concrete Structures

This work proposes that a non-bleeding modified asphalt-based grouting material (AG) can be used to improve the durability performance of prestressed tendon (PT) in post-tensioned concrete structures (PTCS). Therefore, durable and mechanical properties of PTs are tested and compared to PTs coated by AG, AH70 matrix asphalt (AH), epoxy resin (ER), respectively. The combined effect of different coatings on diffusion coefficient, strength and ductility are highlighted. Results showed that AG recorded higher enhancing impermeability than ER and exceeded by 1–2 orders of magnitude compared with traditional CG. Compared with the PS and AH, ER and AG can slightly improved the strength of the strands and significantly enhance the ductility by 50% or more. A corrosion constitutive model for different coated strands is proposed, which features excellent applicability and accuracy. Finally, based on the linear weighted sum optimization method, the protective effect of AG has been discussed and validated. Satisfactory responses have been found AG is effective in enhancing the durability of prestressed strands.