By Mark S. Kuhar
Many people wonder about The American Society for Testing and Materials (ASTM). They just assume that those involved with ASTM committees are like mad scientists sitting in laboratories somewhere analyzing arcane data points to micromanage industry knowledge of construction materials’ performance characteristics.
ASTM is actually a globally recognized leader in the development and delivery of international voluntary consensus standards. More than 12,000 ASTM standards are used around the world to improve product quality, enhance safety, facilitate market access and trade and build consumer confidence.
There have been some recent developments in the area of aggregates.
ASTM Subcommittee C09.20
ASTM Subcommittee C09.20 on Normal Weight Aggregates is developing a standard to distinguish between harmful and non-harmful fines in construction aggregate.
Ready mixed, aggregate and asphalt producers will use the ASTM WK36804 Test Method for Rapid Determination of the Methylene Blue Value for Fine Aggregate and Mineral Filler to qualify new material sources and in routine quality control procedures. The proposed standard entails a method that can be performed in the field in about 10 minutes and does not involve the titration and visual assessments typically associated with such testing.
“The methylene blue test has been shown to be an effective indicator of the amount and type of clay present in aggregate and can therefore help to distinguish between harmful and beneficial fines,” said C09.20 member and W.R. Grace and Co. Research & Development Director Eric Koehler. “Once it has been approved, the proposed standard will enable the use of a wider range of sands and limestone fillers in concrete, while also ensuring that these aggregates are of high quality. This will prevent the waste of non-detrimental fines, which must currently be washed out of sand indiscriminately, [and] result in more sustainable use of limited aggregate resources.”
Buyers and sellers of road and paving materials will be the primary users of a proposed standard under Subcommittee D04.94 on Statistical Procedures and Evaluation of Data, part of ASTM International Committee D04 on Road and Paving Materials.
ASTM WK35585, Practice for Data Collection and Resolving Test Result Differences Between Buyer and Seller, will provide a rational dispute resolution practice for contractors or material suppliers and agencies when numbers from two different laboratories on the same product differ. “The goal is to provide a systematic way to resolve differences in a professional atmosphere,” said D04 member James Moulthrop, P.E., a senior consultant with Fugro Consultants Inc., Austin, Texas.
Among the procedures to be described in WK35585 are: documentation to determine acceptable quality material; sample chain of custody; determination of whether data comes from the same population; determination of differences between sets of data; and, determination of assignable cause(s) for differences between test results.
“The proposed standard has been needed to provide users of ASTM Committee D04 standards a rational sequential process for resolving test result differences,” said D04.94 Chairman Ervin Dukatz, P.E., of Mathy Construction Co., Onalaska, Wis., adding that subcommittee participation is open to paving material interests.
A new ASTM International standard will aid in the selection of lightweight aggregate best suited for use in the design and construction of vegetative roof systems. ASTM E2788, Specification for Use of Expanded Shale, Clay and Slate (ESCS) as a Mineral Component in the Growing Media and Drainage Layer for Vegetative (Green) Roof Systems, was developed by Subcommittee E60.01 on Buildings and Construction, part of ASTM International Committee E60 on Sustainability.
Specifiers, blenders and users of lightweight growing media for green roof applications will be the primary users of ASTM E2788.
According to Chuck Friedrich, an E60.01 member, ASTM E2788 provides typical gradations, physical and chemical properties of the rotary kiln expanded lightweight aggregates that can be used as a lightweight fill, drainage material or as growing media component for green roofs.
“ASTM E2788 can be used to select the size and type of lightweight aggregate best suited for a project,” said Friedrich, of the Carolina Stalite Co. “The selection will be determined by local availability, but the new standard gives a broad scope of the properties that will allow most ESCS products in each region to meet the specification.”
According to Friedrich, ESCS is regularly manufactured for use in the lightweight concrete industry but is also desirable for most green roof media.