Recommendation of RILEM TC 283-CAM: performance-based assessment of alkali-activated concrete durability using the 10 V rapid chloride permeability test

The major barriers to the widespread adoption of alkali-activated materials by the construction industry include concerns about durability and their exclusion from current standards. The chemical reactions characterizing alkali-activated binder systems differ drastically from the conventional hydration process of Portland cement. Thus, the mechanisms by which concrete achieves potential durability are different between the two types of binders. RILEM Technical Committee (TC) 283-CAM (Chloride transport in Alkali-activated Materials) aimed to address key questions related to chloride transport in alkali-activated binders and concretes, with a view toward drafting recommendations for the appropriate selection and application of testing methods, and this document represents a key output of that TC.

The standard ASTM C1202 Rapid Chloride Permeability Test (RCPT) method fails to measure the charge passed through most alkali-activated concretes due to samples overheating when applying the specified 60 V potential difference. A modified RCPT using a 10 V potential difference was used in the interlaboratory testing campaign of TC 283-CAM. The 10 V-RCPT method described in this Recommendation allowed the successful completion of tests for all alkali-activated concretes considered. Various precursors were investigated including fly ash, GGBS, calcined clay and ferronickel slag. 10 V-RCPT results are validated against ASTM C1556 bulk diffusion test results. Performance-based specifications are proposed.