摘   要：为了研究拉伸荷载作用下混凝土的抗渗性，本文通过试验研究了拉伸荷载下水灰比、矿物掺合料、引气剂掺量和纤维掺量等对混凝土气体表面渗透系数的影响。结果表明，水灰比越小，气体表面渗透系数随极限荷载比例的变化趋势越小，当水灰比大于0.4，极限荷载比例大于30%时，气体表面渗透系数随极限荷载比例的增大急剧增长；粉煤灰和矿渣的加入都能不同程度改善混凝土的抗渗性能，其中当粉煤灰掺量为10%左右时，气体表面渗透系数最小，低极限荷载比例下矿渣对抗渗性能的改善效果优于粉煤灰，而在高极限荷载比例下情况相反；引气剂的加入会使混凝土的抗渗性有所降低；加入适量纤维能明显改善混凝土在拉伸荷载作用下的抗渗性，且使抗渗性能出现明显劣化的极限荷载比例显著增大，纤维掺量宜在1.0%左右。

Abstract: In order to study the effect of impermeability of concrete under tensile load, the influences of water cement ratio, mineral admixture, air entraining and fiber content on gas permeability coefficient of concrete surface under tensile load are studied in this paper. The results show that water cement ratio is smaller, the change trend of surface gas permeability coefficient with the ultimate load proportion is smaller, when the water cement ratio is greater than 0.4, the limit load ratio is greater than 30%, the increase of surface gas permeability coefficient with the growth of the ultimate load ratio is rapidly. Fly ash and slag can improve the impermeability of concrete properties of different level, when the dosage of fly ash is about 10%, the surface of the gas permeability coefficient is minimal, lower limit load ratio to improve the performance of slag against seepage effect is better than that of fly ash, and under the high proportion of limit load is opposite. The addition of air-entraining agent can make the permeability resistance of concrete decreases, adding appropriate fiber can obviously improve the permeability resistance of concrete under tensile load, and the permeability in the significant increase in the proportion limit load of a significant degradation, fiber content should be in about 1%.