Effects of shrinkage-reducing admixtures on autogenous shrinkage in alkali-activated materials

International Conference Building Materials, Products and Technologies

材料科学;工业技术（总论）

Kotrla, J.^1 ; Soukal, F.^1 ; Bilek, V.^1 ; Alexa, M.^2

Brno University of Technology, Faculty of Chemistry, Purkyova 118, Brno

61200, Czech Republic^1

Brno University of Technology, Faculty of Civil Engineering, Vevei 331/95, Brno

60200, Czech Republic^2

关键词: Alkali activation;    Autogenous shrinkage;    Calorimetric measurements;    Chemical admixture;    Chemical process;    Concrete technology;    Hydration process;    Shrinkage reducing admixtures;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/583/1/012023/pdf
DOI  :  10.1088/1757-899X/583/1/012023

来源: IOP

【 摘 要 】

This paper deals with possible solutions of chemical and autogenous shrinkage of alkali-activated blast furnace slag (AAS). Shrinkage is the main reason why AAS is not used in practice. One of the solutions how to reduce the shrinkage is the utilization of special chemical admixtures. In concrete technology, the use of chemical compounds based on hydrocarbon alcohols is well known, however the efficiency in AAS is still very poorly elucidated. Therefore, isopropanol was used in this study. The main aim of the work was to recognize and study the relations between chemical processes in the early stages of hydration. The effect of isopropanol on alkali activation was determined by calorimetric measurements and compared with the initial and final setting time of binder. It was found out that the presence of isopropanol additive had only insignificant effect on the setting time. On the other hand, the results indicated that an increasing amount of isopropanol deaccelerates the hydration process which was represented by smaller amount of primary CSH gel formation and delayed time of secondary binder phase formation.