Synthetic alkali-silica reaction (ASR) gels were produced and tested to investigate the effects of chemical composition (Ca/Si, Na/Si, and K/Si atomic ratios) on the gels’ free swelling strain (εg,fr) and restrained swelling pressure (Prs). The gels were cast into disk-shape molds and exposed to distilled water after curing. Each gel's εg,fr was recorded over a period of 28 days, followed by measuring Prs, defined as the pressure required to fully reverse and eliminate the gel's free swelling under a drained configuration. Regression models were developed linking gels compositions to their swelling properties. The outcomes show that Na/Si and K/Si monotonically increase εg,fr. Increasing Ca/Si up to 0.23 drastically reduces εg,fr; higher Ca/Si has modest effect on free swelling. Prs increases by increasing calcium up to a pessimum Ca/Si level; Prs decreases for higher Ca/Si. The value of (Ca/Si)pess is related to the alkali content of the gel. Prs also increases by increasing the gel's alkali content, while a (Na/Si)pess exists in the range 0.85-0.95. These observations are linked with the roles of alkalis and calcium in modifying the silica gel network.
All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- Materials Chemistry