The viscoelastic behavior of synthetic alkali-silica gels at ambient temperature

Interdisciplinary study of alkali-silica reaction (ASR) helps to relate the many aspects of the complex reaction. By combining gel synthesis, rheological measurements, and Raman spectroscopy a quantitative picture of the viscoelastic behavior of ASR products is achieved. Six ASR gels were synthesized with compositions based on Na/Si, K/Si, and Ca/Si ratios seen in previous research/field gels. Li+ was added to Na+ and K+ gels to assess its contribution to gel behavior due to its use in mitigation strategies. Analysis of the gels indicated that polymerization of the SiO2 into 3-dimensional viscoelastic networks took place over time and was dependent on the concentration and type of cations. Ca2+ gels exhibited a higher level of gel network strength earlier than Na and K-dominated gels. The addition of Li+ to Na+ gels reduced the viscoelastic behavior while K+ gels with added Li+ had increased viscosity, viscoelastic behavior and more Q4 production.