2015 CSCE Annual Conference Regina - Building on our Growth Opportunities Conference
Oxidation of sulphide-bearing aggregates can result in severe damages in concrete structures. The mechanism of damage is believed to consist of two steps: (a) oxidation of the aggregate associated with an increase in volume, and (b) formation of sulphuric acid. Both steps produce damage to concrete. This presentation presents an investigation into developing accelerated test method that can be used to evaluate the potential of sulphide-bearing aggregate to oxidize and cause damage to concrete. Different aggregates are tested using different testing regimes. It was found that the level of damage increases with the increase in the level of sulphide content in the aggregate. Cycles of wetting in lime water at 23oC/drying at 60oC and 5oC/drying at 60oC produced some expansion in concrete samples. The use of oxidizing agent was found to accelerate the expansion; however, the obtained expansion was also affected by the length of the soaking and heating cycles.