TY - JOUR
T1 - Effect of metakaolin on the autogenous shrinkage of alkali-activated slag-fly ash paste
AU - Li, Zhenming
AU - Liang, Xuhui
AU - Chen, Yun
AU - Ye, Guang
PY - 2021
Y1 - 2021
N2 - The high autogenous shrinkage of alkali-activated materials made from slag and fly ash is recognised as a major drawback with regard to the use as construction materials. In this study, metakaolin was introduced into the alkali-activated slag-fly ash (AASF) paste to mitigate the autogenous shrinkage. The shrinkage mitigation mechanism of metakaolin was explained by studying the influences of metakaolin on the microstructure, shrinkage related properties, and mechanical properties of AASF paste. It was found that adding metakaolin could significantly reduce the chemical and autogenous shrinkage of AASF paste. This shrinkage mitigation is accompanied by a decrease in the alkalinity of AASF paste pore solution, a reduced drop in internal relative humidity, and an increase in porosity of AASF paste. Moreover, the incorporation of metakaolin does not change the type of the reaction products, but greatly delays the formation of the reaction products of AASF paste. The addition of metakaolin, above 5% of the binder, results in lower 28-day compressive and flexural strength of AASF paste.
AB - The high autogenous shrinkage of alkali-activated materials made from slag and fly ash is recognised as a major drawback with regard to the use as construction materials. In this study, metakaolin was introduced into the alkali-activated slag-fly ash (AASF) paste to mitigate the autogenous shrinkage. The shrinkage mitigation mechanism of metakaolin was explained by studying the influences of metakaolin on the microstructure, shrinkage related properties, and mechanical properties of AASF paste. It was found that adding metakaolin could significantly reduce the chemical and autogenous shrinkage of AASF paste. This shrinkage mitigation is accompanied by a decrease in the alkalinity of AASF paste pore solution, a reduced drop in internal relative humidity, and an increase in porosity of AASF paste. Moreover, the incorporation of metakaolin does not change the type of the reaction products, but greatly delays the formation of the reaction products of AASF paste. The addition of metakaolin, above 5% of the binder, results in lower 28-day compressive and flexural strength of AASF paste.
KW - Alkali-activated materials
KW - Fly ash
KW - Metakaolin
KW - Shrinkage
KW - Slag
UR - http://www.scopus.com/inward/record.url?scp=85100252853&partnerID=8YFLogxK
U2 - 10.1016/j.conbuildmat.2021.122397
DO - 10.1016/j.conbuildmat.2021.122397
M3 - Article
AN - SCOPUS:85100252853
SN - 0950-0618
VL - 278
JO - Construction and Building Materials
JF - Construction and Building Materials
M1 - 122397
ER -