Citation
  • Tagnit-Hamou, A., Thomas, M., Kenai, A., and Kasaniya, M. (2024). Methods for evaluating the reactivity of supplementary cementitious materials for use in concrete. Canadian Standards Association, Toronto, ON.

Executive Summary

Concrete mixtures containing pozzolans have shown exceptional durability performance for millennia [1]. However, given the potential decline in the supply of today’s most widely used supplementary cementitious materials (SCMs) such as fly ash and slag, there is a need to explore options to meet the ever-growing demand for alternative binder materials. The primary objective of this research was to evaluate current test methods and to establish a robust and replicable test method for accurately measuring the chemical (pozzolanic) reactivity of pozzolans, as well as to set an activity limit for their acceptance for use in concrete.

A comprehensive range of material types were assayed in this project, encompassing 10 distinct sources with varied properties. Further, four methods were used to assess the reactivity of pozzolanic materials:

  • ASTM C1897-20, Standard Test Methods for Measuring the Reactivity of Supplementary Cementitious Materials by Isothermal Calorimetry and Bound Water Measurements at 40°C and 23°C
  • CSA A3004-E1-18 Annex A, Standard practice for the evaluation of alternative supplementary cementing materials (ASCMs) for use in concrete as SCMs using the “Pozzolanic activity index with lime” test
  • UNB Lime Activation Test
  • ASTM C311/C311M-22, Standard test methods for sampling and testing fly ash or natural pozzolans for use in portland-cement concrete (strength activity index with portland cement)

The testing was done at the laboratory of the Université de Sherbrooke (UdS) followed by a round robin test at seven different laboratories including UdS.

The results provided a comprehensive approach for enhancing the assessment of supplementary cementitious materials. Overall, the CSA A3004-E1 Annex A method demonstrated reliable repeatability and effective discrimination between reactive and non-reactive materials. A recommendation was made to reduce the seven-day compressive strength limit from 5.5 to 5 MPa.

  1. E.R. Grist, K.A. Paine, A. Heath, J. Norman, and H. Pinder, “Structural and durability properties of hydraulic lime–pozzolan concretes,” Cement and Concrete Composites, vol. 62, pp. 212–223, Sep. 2015. [Online]. Available: https://www.sciencedirect.com/science/article/abs/pii/S0958946515300020