Prof. Zhenming Li, Gustavo Colonnetti medalist 2024

Speaker: Prof. Zhenming Li, Gustavo Colonnetti medalist 2024

Title: Autogenous shrinkage of alkali-activated materials

Alkali-activated materials (AAMs) are eco-friendly alternatives to ordinary Portland cement, but they can show poor volume stability, such as larger shrinkage. In this presentation, I will summarise my research outcomes on autogenous shrinkage of AAMs in the past 5 years. Specifically, I will discuss the testing methods, the magnitude, the mechanism, the prediction, the consequence, and the mitigation of autogenous shrinkage of AAMs. It will be shown that the composition, especially the calcium content, of the raw materials determines whether self-desiccation is the dominant shrinkage mechanism of AAMs. Time-dependent deformation accounts for a large part of the autogenous shrinkage of slag-based system, thus must be considered in shrinkage estimation. Local creep/relaxation helps to release shrinkage-induced tensile stress but exacerbates the development of microcracking. For slag based AAMs, internal curing or addition of aluminosilicate phases could be promising shrinkage-mitigating strategies. A clear understanding of autogenous shrinkage is vital to analyse drying and thermal deformations of AAMs.

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