New ASTM C09 guide gauges mix performance, material compatibility

Sources: ASTM International, West Conshohocken, Pa.; CP staff

ASTM Subcommittee C09.48 on Performance of Cementitious Materials and Admixture Combinations’ working document, WK40615 Guide for Comparing Performance of Concrete Materials Using Mortar Mixtures, standardizes longstanding material-performance investigation protocol.

“This diagnostic tool will provide concrete technologists with useful defined mortar procedures to help anticipate an incompatibility of previously untested material combinations, or to troubleshoot unexpected concrete performance,” says Ara Jeknavorian, consultant and Grace Construction Products veteran.

The guide will assist suppliers, producers, testing labs and government agencies with material selection and quality control processes. Technologists can use one of its mortar tests to compare the relative workability, workability retention, set time, strength, and air content of two or more combinations of cement, sand, admixture, and fly ash. Test results could indicate that a change in material properties might favorably or unfavorably impact concrete performance. Results could also flag a potential material incompatibility that could become evident from poor concrete workability, high air content or delayed set times.

“Should a discrepancy occur between parties on whether a particular material may be responsible for an unexpected concrete performance, the guide will enable two or more labs to conduct the same test procedures to help come to a consensus cause of the problem,” Jeknavorian notes.

Subcommittee C09.48 is part of ASTM Committee C09 on Concrete and Concrete Aggregates, whose next meeting is June 24-28 at the Sheraton Hotel & Marina, San Diego.