AUTHOR=Xupeng Chen , Zhuowen Sun , Jianyong Pang 

TITLE=Study on Metakaolin Impact on Concrete Performance of Resisting Complex Ions Corrosion

JOURNAL=Frontiers in Materials

VOLUME=Volume 8 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/materials/articles/10.3389/fmats.2021.788079

DOI=10.3389/fmats.2021.788079

ISSN=2296-8016

ABSTRACT=the tests conducted in this study are mainly to verify the Metakaolin (MK) impacts on the concrete durability when the concrete suffers joint corrosion by SO42-,Mg2+ and Cl-. A total of 4 groups of concrete test blocks with different MK contents are tested to see their physical property changes and macro-morphology differences during the cyclic process. And a series of approaches, including XRD,FTIR,SEM, and EDS, are applied to study the concrete phase composition changes and the micro-morphology features of all groups. The results show that, when reaching 20 cycles, the concrete mixed with 10% MK shows the best concrete physical properties; when reaching 120 cycles, the concrete with 5% MK admixture shows the best durability, produces corrosion products in quantity similar to ordinary concrete, presents relatively compacted micro-structure and small internal porosity. Mg2+ actually has a great impact on Metakaolin. The corrosion product quantity increases significantly when MK admixture reaches 15%. The great number of produced M-S-H makes the corrosive ions damage the concrete for a second time, leading to serious aggregate peeling-off, powder surface of test block, and porous micro-structure.