A new screening test to evaluate the presence of oxidizable sulphide minerals in coarse aggregates

- A test method was proposed to assess the possible oxidation of sulphide-bearing aggregates.
- The proposed method produces two outputs to screen aggregates.
- The test was applicable for the thirty aggregates tested in this study.
- Possible improvements to the test methods are discussed.

A simple screening test was proposed in order to test coarse aggregates for their potential to cause damage when used in concrete due to the oxidation of sulphide phases. The test involves submerging an aggregate sample in an oxidizing agent and measuring the mass loss. Samples with no known oxidizable sulphides showed a mass loss of <1.0% after one week of testing at room temperature. Samples of oxidizable sulphides showed a mass loss higher than 3.5% and changes in the colour of the test solution. It is proposed that aggregates which achieve a mass loss of less than 0.50% and no colour change in the test solution be accepted.