Abstract
This study aims to develop the calcium sulfoaluminate cement-based engineered cementitious composites (CSA-ECC) to enhance the resistance of newly placed concrete against vibration-induced damage during highway bridge widening. The effects of vehicle-bridge coupled vibration on the mechanical properties of CSA-ECC including compressive strength, flexural strength and flexural toughness were investigated. The results indicate that the volume percentage of coarse air bubbles (> 1.0 mm3) decreases from 54.70–25.94%, and the volume percentage of micro air bubbles (0-0.2 mm3) increases from 30.89–54.19%. As a result, the microstructure of matrix and fiber/matrix interface are densified due to the redistribution of air bubbles caused by the coupling vibration. Therefore, the application of vibration significantly enhances the flexural strength and flexural toughness of CSA-ECC, ascribing to stronger matrix fracture toughness and fiber/matrix interfacial frictional bond. The digital image correlation (DIC) analysis also indicates that vibration delays the occurrence of main cracking and leads to more obvious multi-cracking characteristics. These indicate that the CSA-ECC has a promising application scenario in highway bridge widening projects with exceptional vibration-induced damage resistance ability.