Work

Crack-mediated chloride ingress in ECC-replaced negative moment regions under sustained loading

Year: 2026

Type: article

Abstract: This study investigated crack-mediated chloride ingress in negative moment regions with local engineered cementitious composite (ECC) replacement under sustained loading. Different cracking states were generated at sustained load levels of 0.3 P max , 0.5 P max , and 0.7 P max , followed by 25, 50, and 70 chloride wet–dry cycles. Crack characteristics, effective chloride ingress paths, penetration depth, chloride content, and phase evolution were evaluated. ECC changed the cracking mode from localized wide cracking in normal concrete (NC) to distributed fine cracking. However, the increased number of surface-visible cracks in ECC did not lead to a proportional increase in effective chloride ingress paths. Only 40.0–52.9% of the surface-visible cracks in ECC developed into effective chloride ingress paths, compared with 84.6% for NC at the same load level. The maximum chloride penetration depth was limited to 17 mm in uncracked ECC, whereas crack-mediated penetration ranged from 46 to 145 mm. Chloride content at the 20 mm cover depth generally increased with crack width and sustained load level and decreased nonlinearly along effective ingress paths. Increasing wet–dry exposure mainly promoted chloride accumulation within established paths rather than systematically extending the maximum penetration depth. XRD analysis detected Friedel’s salt at the cover depth, providing qualitative evidence of partial chloride binding. These results demonstrate that local ECC replacement improves chloride resistance primarily by limiting the development of surface cracks into effective inward transport paths.

Source: Construction and Building Materials

DOI: 10.1016/j.conbuildmat.2026.148505