Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Effect of metakaolin on the autogenous shrinkage of alkali-activated slag-fly ash paste
Highlights Metakaolin is applied to mitigate the autogenous shrinkage of alkali-activated slag and fly ash. The reaction products and microstructures are characterized investigated. Mechanical properties of the paste are studied. Metakaolin has a promising potential to be used as an additive in alkali-activated slag and fly systems.
Abstract 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.
Effect of metakaolin on the autogenous shrinkage of alkali-activated slag-fly ash paste
Highlights Metakaolin is applied to mitigate the autogenous shrinkage of alkali-activated slag and fly ash. The reaction products and microstructures are characterized investigated. Mechanical properties of the paste are studied. Metakaolin has a promising potential to be used as an additive in alkali-activated slag and fly systems.
Abstract 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.
Effect of metakaolin on the autogenous shrinkage of alkali-activated slag-fly ash paste
Li, Zhenming (Autor:in) / Liang, Xuhui (Autor:in) / Chen, Yun (Autor:in) / Ye, Guang (Autor:in)
12.01.2021
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch