The Market Monitor Minding the Nation's Business
A new ASTM International standard will help with efforts to enhance the cement content in concrete while also reducing carbon dioxide emissions during production.
The new specification (C1797, Specification for Ground Calcium Carbonate and Aggregate Mineral Fillers for Use in Hydraulic Cement Concrete) was developed by ASTM International’s committee on concrete and concrete aggregates (C09).
ASTM member Caroline Talbot notes that the new standard covers the use of ground calcium carbonate (a type of limestone) and aggregate mineral fillers used in concrete.
“Limestone and fillers can help optimize concrete mix design in terms of workability and finishing by improving packing density,” said Talbot, national technical service manager, Euclid Chemical. “Notably, this will reduce the amount of cementitious product needed for concrete production, making it more environmentally friendly alternative.”
Better packing density improves both plastic and hardened properties, including shrinkage, according to Talbot. In addition, there are indications that the presence of ground limestone enhances the hydration of cement and fly ash.
The new standard will be useful to anyone who produces, or otherwise works with, concretes, as well as other materials. Materials covered by the standard have been used around the world for years; C1797 will allow these companies to show that their materials can be used in concrete without negatively affecting fresh or hardened properties, leading to cost savings and environmental sustainability.
Meanwhile, a new standard provides a test method that uses a specialized tool to prepare samples of and to test the density of roller compacted concrete (RCC). This will help companies that design mixes of RCC as well as laboratories that test RCC.
The new standard (C1800, Test Method for Determining Density of Roller Compacted Concrete Specimens Using the Gyratory Compactor) was created by ASTM International’s Committee on Concrete and Concrete Aggregates (C09). It standardizes laboratory procedures used to determine the density of RCC and allows for the development of potential RCC mixes to be used in the field.
Though it is made with the same ingredients as conventional concrete, RCC is a drier mix. While it was originally used for more specialized applications, RCC can now be used for any kind of heavy duty pavement. RCC mix designers will benefit most from this standard, as it provides a method for assessing and comparing various RCC mixes.