Influence of the Devitrification of the Glass in Porous Aggregates on the Resistance to Alkali in Cement

The corrosive effect of alkali in the cement (ASR interaction) on porous aggregates — foam ceramic and geofoamsitals (analogs of foam glass and foam sitals) in an alkaline medium modeling the liquid phase of setting cement was investigated. It was found that the devitrification of glass melt in the process of thermoactivated pore formation increases the ASR-tolerance of foam ceramic aggregates provided that the crystals are uniformly distributed over the wall thickness of the pores. It is shown that in an alkaline medium the active surface of foam ceramic aggregates is encapsulated by crystalline Ca-, Na-aluminosilicates and subsequent ASR interaction ceases.