Numerical models are helpful vehicles for understanding and describing the engineering properties of construction materials. With the rapid development of both computational capabilities and theoretical insights into chemical reactions, there have been increasing research activities around the globe and raising demands for computational methods that describe different characteristics of alkali-activated materials. In this Chapter, we summarized the collective efforts performed on modelling and simulation of alkali-activated materials in the past two decades and highlighted the most relevant results and advances in the aspects of atomistic simulation, thermodynamic modelling, kinetics modelling, microstructure simulation, and multi-scale modelling. It can be concluded that pioneering work on modelling and simulation of alkali-activated materials has been conducted with fruitful results. However, there are still deficiency gaps and challenges in modelling and simulation of alkali-activated materials, especially in comparison with PC-based materials.

Alkali-activated materials (AAMs) are a class of potentially eco-friendly construction materials that can contribute to reduce the environmental impact of the construction sector by offering an alternative to Portland cement (PC). With the rapid development of both computational capabilities and theoretical insights into alkali-activation reaction processes, there has been a surge in research activities worldwide, leading to a growing demand for computational methods that can describe different characteristics of AAMs. This review summarizes the collective efforts made in the past two decades on this topic, and highlights the most relevant results and advances in the aspects of atomistic simulation, thermodynamic modeling, microstructure/−based simulation, and multi-scale modeling. The gaps and challenges in current numerical research on AAMs are pointed out and discussed in comparison with PC-based materials. This review aims to provide a critical overview of the state-of-the-art in modeling and simulating AAMs, while also outlining potential avenues for future development.

This review provides a comprehensive analysis of the fatigue behaviour of cementitious materials, focusing on the characterisation, modelling, and mechanisms underlying their fatigue properties. It begins with a detailed exploration of how material composition and loading conditions influence fatigue performance, along with the underlying mechanisms that govern fatigue fracture processes. The review also synthesises current advanced experimental methods for characterising fatigue damage evolution, highlighting significant achievements and methodological innovations. It also examines theoretical approaches, summarising prominent models and emerging theories that deepen the understanding of fatigue behaviour in cementitious materials. Meanwhile, the paper reviews computational techniques based on fracture mechanics, damage mechanics, statistical analysis, machine learning algorithms and multiscale modelling, assessing their potential to improve the accuracy of fatigue predictions. Lastly, the review identifies crucial research gaps and outlines future directions, particularly in understanding fatigue-related coupling mechanisms to enhance the fatigue resistance and durability of cementitious materials.

This work evaluated the reactivity and leaching potential of municipal solid waste incineration (MSWI) bottom ash as supplementary cementitious material (SCM) and precursor for alkali-activated materials (AAM). The chemical composition of the amorphous phase in MSWI bottom ash was found to be in the same range as that of Class F coal fly ash. The reactivity of MSWI bottom ash as SCM and AAM precursor was tested to be much lower than that of blast furnace slag, but similar to that of Class F coal fly ash. The method of thermodynamic modeling was found useful in providing references for the mix design of MSWI bottom ash-based AAM. Grinding MSWI bottom ash into powder for the application of SCM and AAM precursor increased its leaching potential. Based on the findings of this study, recommendations were provided on how to use MSWI bottom ash to prepare blended cement pastes and AAM.

Thermodynamic parameters of chloride and sulfate intercalated hydrotalcites were deduced. The phase evolutions in alkali‑activated slag cement upon only sodium chloride or only magnesium sulfate attack and combined attack of those two salts were investigated via thermodynamic modelling. Friedel's salt was predicted to form under sodium chloride attack， while monosulfate， ettringite， gypsum， magnesium silicate hydrate and sulfate intercalated hydrotalcite were predicted to form upon magnesium sulfate attack. The combined attack of sodium chloride and magnesium sulfate exhibited not only characteristics by single attack of those two salts but also coupling effects which promoted the formation of chloride intercalated hydrotalcite and inhibited the formation of Friedel's salt and magnesium silicate hydrate. An increase of the magnesium sulfate proportion led to lower capacity of chemically binding chloride.