Capillary suction induced water absorption and chloride transport in non-saturated concrete: The influence of humidity, mineral admixtures and sulfate ions

• Published in: Construction & building materials 2020-03, Vol.236, p.117581, Article 117581
• Main Authors: Honglei, Chang, Zuquan, Jin, Tiejun, Zhao, Benzhen, Wang, Zhe, Li, Jian, Liu
• Format: Article
• Language: English
• Subjects: Capillary suction; Chloride; Concrete; Water absorption
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2019.117581

•Seawater and NaCl-Na2SO4 composite solution are used as the aggressive solution in experiments.•Water absorption and chloride transport induced by short time capillary suction are characterized.•Influence of internal humidity, mineral admixtures, and sulfate ions are discussed.•Relation between water absorption and chloride penetration under short time capillary suction condition are evaluated. 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.