Concrete Products

SEP 2012

Concrete Products covers the issues that attract producers of ready mixed and manufactured concrete focusing on equipment and material technology, market development and management topics.

Issue link: http://concrete.epubxp.com/i/82325

Contents of this Issue

Navigation

Page 19 of 59

NEWS SCOPE READY MIXED NRMCA expands Technology in Practice series The National Ready Mixed Concrete Associa- tion has introduced three new topics—bring- ing the total to eight—in its Technology in Practice (TIP) series of information sheets for industry personnel to educate themselves on general quality control/quality assurance and technical topics. The three new topics are TIP 6: Aggregate Moisture and Making Adjustments to Con- crete Mixtures, which outlines concepts on aggregate moisture for mixture proportion- ing and production of concrete; TIP 7: Cre- ating and Using Three Point Curves for Laboratory Trial Batches, which details the process of developing lab trial batch infor- mation for mixture submittals; and, TIP 8: Concrete Yield, which lays out the process for determining yield of concrete and eval- uating problems with yield. TIPs are modeled on NRMCA's Concrete in Practice series. While CIP was developed as basic technical topics for the ready mixed in- dustry to use with its customers or others in- volved in concrete construction, the TIP series is written for ready mixed concrete industry personnel to support internal education on general quality control/quality assurance and technical topics. The TIPs cover topics on standards and testing and are written in a simple format with numerical examples when appropriate. The other five topics available for the TIP series are: TIP 1: Quantifying Concrete Quality—provides ideas on identifying items to measure and quantify the impact of a quality goal that pos- itively impacts the company's bottom line; TIP 2: Establishing the Required Average Strength of Concrete—summarizes the general process of establishing the required strength for concrete based on the strength specified in project specifications in accor- dance with ACI standards; TIP 3: Aggregate Sampling for Laboratory Tests—discusses procedures to ensure that samples obtained for quality control tests are representative of the stockpiles or other stor- age locations from where they are obtained; TIP 4: Aggregate Sample Reduction for Labo- ratory Tests—addresses procedures to prop- erly reduce the size of a larger field sample to a smaller size that is required for laboratory tests; and, TIP 5: Capping Cylindrical Concrete Specimens with Sulfur Mortars and Unbonded Caps— summarizes the key points in the applicable standards for capping strength specimens and the reasons for these requirements. Portions of each TIP topic can be viewed and purchased on the NRMCA website or by con- tacting NRMCA's Jacques Jenkins at jjenk- ins@nrmca.org, or 888/846-7622, ext. 1165. Proposed ASTM fines test could widen range of concrete-grade aggregate ASTM Subcommittee C09.20 on Normal Weight Aggregates, part of Committee C09 on Concrete and Concrete Aggregates, is developing a standard to distinguish be- tween harmful and non-harmful fines in construction aggregate. Ready mixed, aggregate and asphalt pro- ducers 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 pro- cedures. 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 typi- cally 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," says 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 indiscrim- inately, [and] result in more sustainable use of limited aggregate resources." Committee contacts: (technical) Eric Koehler, W.R. Grace, Cambridge, Mass., 617/957-8588, eric.koehler@grace.com; (ASTM staff liaison) Scott Orthey, 610/832- 9730; sorthey@astm.org. 18 | SEPTEMBER 2012 WWW.CONCRETEPRODUCTS.COM

Articles in this issue

Links on this page

Archives of this issue

view archives of Concrete Products - SEP 2012