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.

在本文中，通过在 LSECC 梁中预诱导弯曲裂纹，研究了低收缩工程水泥基复合材料 (LSECC) 中裂纹对氯化物渗透的影响。具有不同裂纹宽度的裂纹梁用 3% 重量的氯化钠溶液浸泡，从梁底部开始进行浸泡和干燥循环。在测试中应用了四种水与粘合剂比为 0.20、0.25、0.30、0.35 且纤维含量相同的 LSECC 混合物。通过在选定点用电锤钻孔粉末样品来确定沿裂纹路径及其邻近位置的光束中氯离子的含量。测试结果表明： 1) LSECC 中使用更高的基体强度或更低的水与粘合剂比导致非开裂 ECC 中更高的氯化物渗透阻力；2) 对于破解的 LSECC，当裂纹宽度小于临界值时，未观察到裂纹对复合材料氯化物渗透的影响；3）根据目前的研究，LSECC-0.20、LSECC-0.25和LSECC-0.30的临界裂纹开口分别位于0.0625和0.1043 mm、0.0467-0.0952 mm和0.0435-0.0870 mm之间；4) 由于裂纹宽度大于临界值，而小于一定值，10 次浸泡干燥后沿裂纹路径或裂纹附近的氯离子含量仍小于粘结剂重量的0.3%循环。25 和 LSECC-0.30；4) 由于裂纹宽度大于临界值，而小于一定值，10 次浸泡干燥后沿裂纹路径或裂纹附近的氯离子含量仍小于粘结剂重量的0.3%循环。25 和 LSECC-0.30；4) 由于裂纹宽度大于临界值，而小于一定值，10 次浸泡干燥后沿裂纹路径或裂纹附近的氯离子含量仍小于粘合剂重量的0.3%循环。