Concentration of expansive ASR gel generated due to ASR kinetics increases as time progresses. This simulation result is based on the initial concentration of species considered in this study, no applied loads, constant temperature of 20°C, model geometry and fully saturated conditions. There is a rapid increase in concentration initially and at 5 years it is 0.23 (mol/m3). After 5 years the increment continues at a slower rate than before and concentration becomes 0.255 (mol/m3) at 15 years. After 15 years there is no significant change in concentration until 30 years when maximum concentration becomes 0.257 (mol/m3). In the concrete matrix, distribution of expansive gel varies for different time periods, as visualized in Figure 4. The concentration of expansive ASR gel is higher in the space between closely positioned aggregate particles. It is also found that the concentration of expansive ASR gel is high around the small sized aggregate particles. This is because of the more surface area provided by small particles comparing to larger ones. Actually, expansive gel generated inside the reactive aggregates first followed by aggregate cracking and then cracking in paste. Thus, gel flow along the cracks from the aggregate through the cement paste.
1. Rahman, Md. Asif, Yang Lu, “A Meso-Scale Multiphysics Model for Predicting Concrete Pavement Performance Subject to ASR Degradation,” Transportation Research Board (TRB) Annual Meeting, 2019, Manuscript No. 19-03839R1. DOI