ABSTRACT
The author has developed poromechanical models to predict the expansion progress of concrete due to alkali silica reactions (ASR) and its effect on the time-dependent structural performance of reinforced concrete structures. In this study, the overall strategy of the modeling is summarized, and the directions of future research are also considered. Based on equations for the kinetics of ASR and mass conservations of water, silica and alkali, ASR-gel generation models are formulated; in addition, they are integrated with mechanical models that consider poromechanics wherein, total stresses are accounted as the summation of the stress of concrete skeleton and the pressure of the substances inside pores or cracks. These strongly-coupled models of material and structural phenomena have already been applied to some structural problems of real-scale reinforced concretes (RC), such as shear failure of RC beams and fatigue life simulations of RC slabs. With experimental and analytical studies, some benefits of ASR expansion on structural performance of RC have emerged, such as increased shear capacity of RC beams and prolonged fatigue lives of RC slabs. Meanwhile, several studies in the literature have highlighted the importance of understanding the physical and chemical properties of ASR gels. The microscopic chemical and mechanical observations of ASR gels showed that the calcium contents in ASR gel gradually increases, and this can lead to changes in mechanical properties of the gel (e.g. stiffness, viscosity). The change in properties of ASR gel inside cracks can affect the overall structural performance of ASR-expanded concrete.
