title: Self-immunity microcapsules for corrosion protection of steel bar in reinforced concrete.
abstract: A novel microcapsule-based self-immunity system for reinforced concrete is proposed. Its feasibility for hindering the corrosion of steel rebar by means of lifting the threshold value of [Cl(-)]/[OH(-)] is discussed. Precisely controlled release behavior enables corrosion protection in the case of depassivation. The release process is characterized over a designated range of pH values, and its release characteristics of the microcapsules, triggered by decreasing pH value, are captured by observing that the core crystals are released when exposed to a signal (stimulus). The aim of corrosion protection of steel bar is achieved through the constantly-stabilized passive film, and its stability is promoted using continuous calcium hydroxide released from the microcapsule, restoring alkaline conditions. The test results exhibited that the release process of the microcapsules is a function of time. Moreover, the release rate of core materials could interact with environmental pH value, in which the release rate is found to increase remarkably with decreasing pH value, but is inhibited by high pH levels.
authors.affiliation: Department of Civil Engineering, Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering, Shenzhen University, Shenzhen 518060, P.R. China.
authors.forename: Yanshuai
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Civil Engineering, Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering, Shenzhen University, Shenzhen 518060, P.R. China.
authors.forename: Guohao
authors.initials: G
authors.lastname: Fang
authors.affiliation: Department of Civil Engineering, Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering, Shenzhen University, Shenzhen 518060, P.R. China.
authors.forename: Weijian
authors.initials: W
authors.lastname: Ding
authors.affiliation: Department of Civil Engineering, Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering, Shenzhen University, Shenzhen 518060, P.R. China.
authors.forename: Ningxu
authors.initials: N
authors.lastname: Han
authors.affiliation: Department of Civil Engineering, Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering, Shenzhen University, Shenzhen 518060, P.R. China.
authors.forename: Feng
authors.initials: F
authors.lastname: Xing
authors.affiliation: Department of Civil Engineering, Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering, Shenzhen University, Shenzhen 518060, P.R. China.
authors.forename: Biqin
authors.initials: B
authors.lastname: Dong