Open AccessElectrochemical Performance of Steel Embedded in CSA Concrete and Its Interfacial Microstructure
Author(s) -
Meimei Song,
Qiu Li,
Ke Wu,
Yihua Dou
Publication year - 2020
Publication title -
advances in materials science and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 42
eISSN - 1687-8442
pISSN - 1687-8434
DOI - 10.1155/2020/4761854
Subject(s) - materials science , microstructure , carbonation , cementitious , corrosion , passivation , portland cement , cement , dielectric spectroscopy , composite material , anode , scanning electron microscope , calcium hydroxide , carbon steel , metakaolin , ettringite , porosity , metallurgy , electrochemistry , layer (electronics) , chemical engineering , electrode , chemistry , engineering
Calcium sulfoaluminate cement (CSA) is a low-carbon cementitious material that significantly reduces alkalinity and produces calcium hydroxide-free (CH-free) matrix environment in comparison to ordinary Portland cement (OPC). It might be, however, less efficient towards the passivation of steel in concrete and further investigation before widespread adoption is required. In this project, scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX) on polished samples was employed to provide the interfacial characterization of steel reinforced CSA concrete and study the relationship of interfacial quality and corrosion resistance of the embedded steel. The galvanostatic polarization behavior indicates that the steel embedded in CSA concrete remains passive for 28 days in absence of Cl − ions and carbonation. Microstructure analysis has shown that there is an Al-enriched layer at interfacial zone in CSA concrete with the main hydration product of AH 3 , which is also alkaline and is expected to improve the steel passivity. Furthermore, the interfacial zone has markedly reduced porosity compared to the bulk matrix, which leads to reduced possibility of current flow between anode and cathode and therefore improves the corrosion resistance of the embedded reinforcement.