Study on leaching damage mechanism of calcium ions of reactive powder concrete (RPC) under ion corrosion

• Published in: Construction & building materials Vol. 269; p. 121303
• Main Authors: Li, Jun, Xu, Yan, Tian, Zefeng, Ma, Jie, Jing, Pengfei, Song, Zhenyun
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.02.2021
• Subjects: Calcium leaching damage; Ion corrosion; RPC; Ion corrosion; RPC; Calcium leaching damage
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2020.121303

•The strength damage caused by dissolution and leaching of calcium ions.•·The microscopic structure evolution with chemical corrosion of ion solution.•·A constitutive model of reactive powder concrete (RPC) under the cooperative action of ion corrosion and loading. The damage of dissolution and leaching of calcium ions caused by ion corrosion to the macroscopic mechanical properties of RPC is investigated, and the microscopic mechanism of ion corrosion is revealed. Through the unconfined compression test, the effects of different ion corrosion types on the unconfined compression strength (UCS) and failure morphology of RPC, and standard cement mortar (SCM) were studied. The effect of ion corrosion on the micro-structure and element ratio of hydration products was analyzed by SEM/EDS. In addition, through the calcium leaching model test, the effect of NaCl and MgSO4 corrosion on calcium dissolution and destruction of RPC slabs was studied, and the composition of the precipitate was determined by XRD analysis method. A damage constitutive model of RPC with ion corrosion and loading coupling was established, providing a theoretical basis for calculating the ion corrosion depth. The results show that RPC has better resistance to the damage of calcium leaching caused by ion corrosion than SCM. After 90 days of chloride ion and sulfate ion corrosion, calcium precipitation and recrystallization appeared on the surface of RPC, where an insoluble substance formed, and the ion corrosion depth was 13.32 mm and 11.30 mm, respectively.