Use of a Bulk Resistivity Index to Evaluate the Permeability Performance of Blended Cements and SCMs
Abstract
Most specifications for supplementary cementitious materials focus on reactivity as related to strength development. However, beyond strength, the other major benefit from use of SCMs, whether added separately or in blended cements, is their impact on changing the pore structure of the cementitious matrix resulting in improved resistance to ingress of aggressive fluids, i.e. lower permeability. ASTM C1876 and similar test methods in other standards for assessing the bulk resistivity of concrete already exist, but in 2025, ASTM subcommittee C09.48 on Performance of Cementitious Mixtures has adopted ASTM C1952, a standard test method for assessing the relative bulk resistivity of mortar cubes containing SCMs to that of a Portland cement or Portland -limestone cement control. It is anticipated that this test method will be adopted in materials specifications as a performance indicator for the relative permeability reduction to be expected from use of SCMs and blended cements. This test method is also a better tool than strength activity tests for determining whether a proposed new material is a reactive pozzolan or just an inert filler. Details of the test method, and test results, including precision data are provided.
Keywords
bulk resistivity; blended cements; supplementary cementitious materials.
DOI
10.5703/1288284318171
Recommended Citation
Hooton, Robert Douglas, "Use of a Bulk Resistivity Index to Evaluate the Permeability Performance of Blended Cements and SCMs" (2025). International Conference on Durability of Concrete Structures. 1.
https://docs.lib.purdue.edu/icdcs/2025/mccarter/1
Use of a Bulk Resistivity Index to Evaluate the Permeability Performance of Blended Cements and SCMs
Most specifications for supplementary cementitious materials focus on reactivity as related to strength development. However, beyond strength, the other major benefit from use of SCMs, whether added separately or in blended cements, is their impact on changing the pore structure of the cementitious matrix resulting in improved resistance to ingress of aggressive fluids, i.e. lower permeability. ASTM C1876 and similar test methods in other standards for assessing the bulk resistivity of concrete already exist, but in 2025, ASTM subcommittee C09.48 on Performance of Cementitious Mixtures has adopted ASTM C1952, a standard test method for assessing the relative bulk resistivity of mortar cubes containing SCMs to that of a Portland cement or Portland -limestone cement control. It is anticipated that this test method will be adopted in materials specifications as a performance indicator for the relative permeability reduction to be expected from use of SCMs and blended cements. This test method is also a better tool than strength activity tests for determining whether a proposed new material is a reactive pozzolan or just an inert filler. Details of the test method, and test results, including precision data are provided.
