Experimental study on chloride penetration in cracked engineered cementitious composite under soak-dry cycles

•The crack width that does not influence chloride penetration is determined.•Matrix strength can influence chloride penetration in cracking and non-cracking of ECC.•As crack width is less than 60mm, no influence of cracking on chloride penetration. In the present paper, the effect of cracks in low shrinkage engineered cementitious composite (LSECC) on chloride penetration is investigated by pre-inducing bending cracks in LSECC beams. The cracked beams with different crack width were soaked with 3% in weight of sodium chloride solution undergo soaking and drying cycles from the bottom of the beams. Four LSECC mixtures with water to binder ratio of 0.20, 0.25, 0.30, 0.35 and with the same fiber content were applied in the tests. The content of chloride ion in the beam along the crack path and its neighboring places was determined by drilling powder sample with electric hammer at the selected point. The test results show: 1) higher matrix strength or lower water to binder ratio used in LSECC leads to higher resistance of chloride penetration in non-cracking ECC; 2) for cracked LSECC, as crack width is less than a critical value, no influence of cracking on chloride penetration of the composites is observed; 3) based on the present study, the critical crack opening is located between 0.0625 and 0.1043 mm, 0.0467–0.0952 mm and 0.0435–0.0870 mm respectively for LSECC-0.20, LSECC-0.25 and LSECC-0.30; 4) as crack width is larger than the critical value, while is less than a certain value, the content of chloride ion along the crack path or at neighbors of the crack is still less than 0.3% of the binder weight after 10 soak-dry cycles.