Capillary suction induced water absorption and chloride transport in non-saturated concrete: The influence of humidity, mineral admixtures and sulfate ions
Capillary suction induced water absorption and chloride transport in non-saturated concrete: The influence of humidity, mineral admixtures and sulfate ions
复制标题
非饱和混凝土中毛细吸力引起的吸水和氯离子传输：湿度、矿物掺合料和硫酸根离子的影响
DOI：
10.1016/j.conbuildmat.2019.117581
复制
发表时间：
2020-03-10
影响因子：
7.4
通讯作者：
Liu Jian
中科院分区：
文献类型：
--
作者：
Chang Honglei;Jin Zuquan;Liu Jian
海洋环境中的混凝土结构会受到毛细吸力引起的氯离子侵蚀的严重危害。为研究不同因素下毛细吸力对混凝土的侵蚀作用，以海水和NaCl-Na 2SO 4溶液为腐蚀介质，获得了不同水胶比、粉煤灰和矿渣掺量以及内部相对湿度条件下混凝土吸水量和氯离子含量的变化规律。结果表明，混凝土内部相对湿度的降低导致混凝土在短时间内通过毛细吸力吸收的海水量增加，促使混凝土表面氯离子含量快速增长。对于早龄期（28 d）混凝土试件，粉煤灰掺量为0-30%或矿渣掺量为0- 50%时，混凝土的吸水率和氯离子含量更容易随掺量的增加而下降。在短时毛细吸力条件下，SO 42-对混凝土吸水率影响较小，但会略微增加氯离子含量。然而，氯离子含量的演变并不符合SO 42-浓度的变化。此外，在短时间内，氯离子含量与毛细吸收量呈线性关系，不宜用氯离子扩散系数来反映毛细吸收作用下混凝土的氯离子迁移速率。(C)2019爱思唯尔有限公司版权所有。
Concrete structures in marine environments are gravely jeopardized by chloride attack caused by capillary suction. To investigate the erosion of concrete induced by capillary suction under various factors, seawater and NaCl-Na2SO4 solution were used as corrosive solution to obtain the evolution law of water absorbed amount and chloride content in concrete with different water to binder ratio, fly ash and slag dosages and internal relative humidity. The results show that the decrease of internal relative humidity leads to the increase of seawater absorbed by capillary suction in a brief period, and boost rapid growth of chloride content in surface of concrete. For early age (28 d) concrete specimens, when the fly ash dosage is 0-30% or the slag dosage is 0-50%, the water absorption rate and chloride content of concrete are more likely to drop with the dosage increasing. Furthermore, under short-time capillary suction condition, SO42- has a minor impact on water absorption of concrete, while slightly increases the chloride content. However, the chloride content does not evolve coincidently with the change of SO42- concentration. Moreover, within a brief exposure period, the chloride content linearly develops with absorbed sweater amount, and it is inappropriate to use chloride diffusion coefficient to reflect the chloride transport rate of concrete under capillary absorption effect. (C) 2019 Elsevier Ltd. All rights reserved.