Sources: Ready Mixed Concrete Research & Education Foundation, Alexandria, Va.; CP staff
A new RMC Research Foundation report based on work at the National Ready Mixed Concrete Association’s College Park, Md. laboratory addresses the lack of a consistent and cost-effective concrete permeability test method. “Reliability of Resistivity Tests of Concrete” authors evaluate mix design and specimen preparation factors that impact resistivity measurement; their conclusions can be incorporated in standards driving agency and engineer specifications in public and private concrete construction.
The report cites the increasing acceptance of a non-destructive, easy to perform electrical test method that predicts concrete permeability and serves as an alternative to prescriptive water/cementitious material ratio specifications. Authors contrast the procedure with the benchmark ASTM C1202 – 19 Standard Test Method for Electrical Indication of Concrete’s Ability to Resist Chloride Ion Penetration, which they characterize as deficient, “more expensive and subject to error by less proficient testing agencies.”
“The current way of specifying for durability is to impose a maximum w/cm limit on concrete,” says 2020 Foundation Chairman Ted Chandler (Chandler Concrete). “Unfortunately, this is not verifiable and does not recognize the significant benefit provided by supplementary cementitious materials. In order to optimize concrete mixtures, we need performance-based specifications to allow for innovation, and we need reliable test methods to be used for quality assurance by specifiers and owners. This research provides us the means to do both.”
“Allowing for optimization of modern concrete mixtures is essential to building sustainable, long-lasting and affordable infrastructure,” notes Executive Director Julie Garbini. The new Foundation report builds on a library of guides and studies behind the industry’s Prescriptive-to-Performance Initiative, aimed at optimizing concrete for strength and durability, sustainability, and improved competitiveness with other building systems, she adds.
“Reliability of Resistivity Tests of Concrete” is posted at www.rmc-foundation.org.
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