Sources: ASTM International, West Conshohocken, Pa.; CP staff
A proposed ASTM standard will provide a test method for properties of fresh roller compacted concrete, its development coinciding with the increasing specification of RCC for highway road base, streets, roads, parking lots and heavy industrial pavements, in addition to long-established water resources structures.
ASTM WK42461, Test Method for Density (Unit Weight) and Air Content (Pressure Method) of Freshly Mixed Roller-Compacted Concrete will suit paving or heavy/civil contractors, testing laboratories, and government agencies. It is being developed by Subcommittee C09.45 on Roller-Compacted Concrete, part of ASTM Committee C09 on Concrete and Concrete Aggregates.
“Measured air content values are used in the design and control of RCC mixtures, especially when the mixture is air entrained,” says ASTM C09.45 member and USDA–Natural Resources Conservation Service Construction Engineer Dennis Clute. “As with conventional concrete, RCC mixtures are proportioned on the basis of absolute volume. Lab mixes are tested for air content to determine the volume of air in the mix in order to adjust the mix proportions to yield one cubic yard.”
Clute notes that RCC quality is proportional to its density. The theoretical density of an RCC mix can be compared to density values obtained by ASTM WK42461 to verify that the mix is well proportioned. If the measured density is much less than that of the theoretical density, it may be necessary to change aggregate gradation or add more fine material to the mix. The proposed standard will be on the C09 agenda during the June (22-25) Committee Week in Toronto. Information on committee or subcommittee participation can be obtained from Dennis Clute, 817/509-3765, email@example.com, or ASTM C09 staff liaison Scott Orthey, 610/832-9730, firstname.lastname@example.org.