Resistance to acid attack of alkali-activated binders: Simple new techniques to measure susceptibility

Two rapid tests were developed to evaluate the resistance to acid attack by ordinary Portland cement (OPC) and alkali-activated pastes. Acid neutralisation capacity (ANC) at pH 7, 4 and 2 was monitored with powdered pastes. In parallel, a 'combined-pH assay' with a single sample was used to sequentially assess ANC at different pH values. A mass loss/consumed acid monitoring technique has been also developed in order to assess monolithic samples. The OPC paste showed the most degradation. Among the alkali-activated pastes, those with the lowest calcium content (fly ash and spent-FCC catalyst) had the best performance.