Following the ASTM C 09 and C 01 committee meeting in early December, National Ready Mixed Concrete Association staff noted prospective additions and
Following the ASTM C 09 and C 01 committee meeting in early December, National Ready Mixed Concrete Association staff noted prospective additions and changes to the C 94 Specification for Ready Mixed Concrete.
Rich Szecsy (Lattimore Materials) succeeds Steve Parker (Trinity Materials), who completed a 10-year term as subcommittee chairman. The subcommittee is working on a proposal to change the ordering information and define associated responsibilities in prescription and performance options. A revision is being proposed regarding the jobsite water addition to allow for systems that control slump by water addition during transit. A ballot item is also proposed for addressing the reuse of plastic concrete and, finally, an item that addresses batching accuracy requirements for silica fume will balloted during the current cycle.
The subcommittee responsible for ASTM C 33, Specification for Concrete Aggregates, is deliberating on a proposal to clarify reporting requirements for aggregate susceptible to alkali silica reactivity. Some revisions to the appendix that provides guidance on ASR tests were approved. The subcommittee is also developing a proposal to permit increased use of crusher fines passing the No. 200 sieve in manufactured sands.
On the cement side, preliminary data was discussed on a (California Department of Transportation) Caltrans study evaluating cements with and without limestone. While cements with limestone additions are now recognized in ASTM C 150 and AASHTO M 85, Caltrans is conducting a large study before it permits such materials’ use in its specification. No significant effects are seen in the preliminary data.
The subcommittee responsible for cement specifications has also developed and balloted a significant revision to ASTM C 1157 Performance Specification for Hydraulic Cement. While the item did not pass the balloting process because of a few technical details, NRMCA staff noted general consensus that this was a significant improvement to the current version of the standard.