Concrete Technology October 2007


10.25.07	www.cement.org/tech If this e-mail does not display correctly, click here to view it in your Web browser.
	...UP CLOSE
	Mass Concrete – How do you handle the heat? Mass concrete is a hot topic. Owners desire long service lives so engineers design concrete mixes for low permeability. These mixes typically have high cementitious material contents, which results in high temperatures within the fresh concrete. To avoid cracking and other temperature related damage to the concrete, contractors must control the maximum temperature and temperature difference between the interior and the surface of the concrete. This can pit the construction schedule against the service life. When all involved parties work together, appropriate changes can be made to achieve the desired service life with minimal impacts to the schedule. The key is an understanding of mass concrete. Selecting an appropriate concrete mix is the first step. More.
	...RELATED RESOURCES
	Save 25% on PCA's New Mass Concrete Publication Due to the increasingly common use of fast-track construction practices and high-performance concretes with high cementitious materials contents, mass concrete issues are being encountered in typical bridge and building placements. Understanding the implications of using mass concrete (high internal temperatures and temperature-related cracking) is key to producing a structure that provides many years of service. Mass Concrete for Buildings and Bridges (EB547) offers practical guidance on working with mass concrete, how to manage concrete temperatures, and prevent or minimize temperature-related cracking. Special introductory price good until November 30, 2007.
	...FREQUENTLY ASKED QUESTIONS
	What test methods are available to determine water-soluble sulfates in soil or water that could be included in a project specification? A: The ACI Building Code (ACI 318) contains requirements for concrete exposed to sulfate solutions; however, no guidance is given for determining the level of sulfates. Four test methods are commonly used in North America to assess sulfate exposure of concrete placed in direct contact with soil. The methods differ in extraction ratio, extraction duration, and sample preparation. More on test methods. New research report on Test Methods for Water-Soluble Sulfates in Soils Click here for more cement and concrete FAQs.
	...DECORATIVE CONCRETE
	Light Reflective Floors Light reflective floors improve illumination inside buildings by reflecting light from both natural and artificial sources. White and light-colored surfaces provide a background that reduces shadows from large machinery, stacked goods, and tall racks. Rather than adding more costly lighting units or increasing their intensity, white floor surfaces provide a passive means of improving illumination. Even as it ages, white concrete continues to reflect a significant amount of light. Improved illumination leads to increased visibility, which is an important consideration for a wide range of buildings, from factories to warehouses to grocery stores and other retail establishments. Light reflective floors create inherently safer facilities, while saving energy and money for building owners. There have also been claims of other benefits associated with people who work in buildings with light reflective floors, such as reduced eyestrain. See Light Reflective Floors for more information on materials and construction used for white concrete floors. Click here for more about architectural and decorative concrete.
	...EDUCATION FOUNDATION
	2007 Fellowship Awards Presented The Portland Cement Association Education Foundation funds educational activities that will increase public knowledge regarding appropriate uses of cement and concrete. Subject areas of interest are concrete technology, residential, public works, masonry, engineered structures, and cement manufacturing. Innovative projects in other areas of cement and concrete technology are also considered. The Foundation recently presented $20,000 each to eight graduate students from North American universities for research projects at PCA’s Joint Fall Meeting in September. More. 2008 Call for Nominations Applications are being accepted for the 2008 awards. They must be received by January 15, 2008. More.
	...WORLD OF CONCRETE
	PCA Offers Free Registration to World of Concrete As a cosponsor of the World of Concrete, PCA offers free registration and reduced costs on seminars. The annual concrete-industry trade show is scheduled for January 21-25, 2008, at the Las Vegas Convention Center. Click here to register online. Click here to download registration form. Click here for more information. Don't miss the seminars given by Michelle Wilson of PCA: Impact of Cement on Properties of Concrete Tuesday, January 22, 8:00 -11:00AM Adding Water on Site: To Add, or Not to Add? Wednesday, January 23, 8:00 -11:00AM Myths in Concrete Construction – The Fundamentals Friday, January 25, 8:00 - 9:30AM
	...NEW RESEARCH
	Evaluation of Potential Concrete Deterioration Related to Magnesium Chloride (MgCl₂) Deicing Salts (SN2770) The use of magnesium chloride (MgCl₂) as a deicing chemical has gained popularity due in part to its ability to significantly reduce the freezing temperature of precipitation. However, some studies report deterioration of concrete in service, possibly the result of chemical attack that weakens the paste structure. The findings from other studies vary greatly, as do some field reports that suggest DOT’s have used the salt solution for as many as 10 years with no subsequent concrete damage. Laboratory tests in this research could not verify a deterioration mechanism related to physical effects such as freeze-thaw scaling and salt crystallization. Although little to no visual deterioration was observed in concrete test specimens, microscopic evaluation indicated minor chemical attack. Long-Life Concrete Pavements in Europe and Canada (SN3033) Long-life concrete pavements require less frequent repair and rehabilitation and contribute to highway safety and improved traffic flow. A fact-finding tour to Canada and several European countries found that concrete pavements there are designed for 30 or more years of low-maintenance service life. Scanning team recommendations for U.S. implementation include constructing pavements in two lifts, developing pavement design catalogs, using better-quality materials in pavement subbases, paying greater attention to cement and concrete mixture properties, using a geotextile interlayer to prevent concrete slabs from bonding to the cement-treated base, and using exposed aggregate surfaces to reduce noise.
	...REGIONAL PROGRAMS
	Pervious Concrete Seminars PCA and the National Ready Mixed Concrete Association have teamed up with Land Development Today magazine to offer the seminar "Pervious Concrete—A Stormwater Solution." Chicago/Skokie, Ill. - October 26, 2007 Portsmouth, N.H. - November 2 , 2007 Jersey City, N.J. - November 5, 2007 Jackson, Miss. - November 16, 2007 Arkansas — February 11, 2008 Charlotte, N.C. — February 18, 2008 Louisville, Ky. — March 17, 2008 Philadelphia, Pa. — April 7, 2008 Hartford, Conn. — April 14, 2008 Omaha, Neb. — April 21, 2008 Complete listing of industry conferences
	... EDUCATION & TRAINING 2008
	Mark Your Calendar for 2008 Skokie Courses Kiln Process January 29-February 1 September 16-19 Mill Grinding February 5-7 September 23-25 Concrete Principles and Practices February 25-28 October 6-9 Troubleshooting: Solutions to Concrete Field Problems March 3-5 October 20-22 Cement and Concrete Overview April 10-11 Aggregates and Admixtures for Use in Concrete September 29-30 Cement Manufacturing for Process Engineers November 10-13 Contact Julie Lisiecki for more information.
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