Concrete Products

AUG 2014

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.

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EDITORIAL BY DON MARSH MINING MEDIA INTERNATIONAL EDITORIAL OFFICE 11555 Central Parkway, Suite 401 Jacksonville, Florida 32224 U.S.A. P: +1.904.721.2925 F: +1.904.721.2930 EDITOR Don Marsh, ASSISTANT EDITOR Josephine Smith, GRAPHIC DESIGNER Michael Florman, EDITORIAL DIRECTOR Steve Fiscor, MINING MEDIA INTERNATIONAL CORPORATE OFFICE 8751 East Hampden Avenue, Suite B-1 Denver, Colorado 80231 U.S.A. P: +1.303.283.0640 F: +1.303.283.0641 PRESIDENT/PUBLISHER Peter Johnson, VP-SALES & MARKETING John Bold, U.S., CANADA SALES Bill Green, GERMAN SALES Gerd Strasman, SHOW MANAGER Tanna Holzer, PRODUCTION MANAGER Dan Fitts, Concrete Products, Volume 117, Issue 8, (ISSN 0010-5368, USPS 128-180) is published monthly by Mining Media Inc., 10 Sedgwick Drive, Englewood, Colorado 80113 ( Periodicals postage paid at Englewood Colorado, and additional mailing offices. Canada Post Publications Mail Agreement No. 40845540. Canada return address: Station A, PO Box 54, Windsor ON N9A 6J5, Email: cir- Current and back issues and additional resources, including subscription request forms and an editorial calander, are available online at SUBSCRIPTION RATES: Free and controlled circulation to qualified subscribers. Non-qualified persons may subscribe at the following rates: USA and Canada, 1 year $72.00, 2 year $119.00, 3 year $161.00. For subscriber services or to order single copies, write to Concrete Products, 8751 East Hampden, Suite B1, Denver, Colorado 80231 USA; call +1.303.283.0640 (USA) or visit www. ARCHIVES AND MICROFORM: This magazine is available for research and retrieval of selected archived articles from leading electronic databases and online search services, including Factiva, LexisNexis, and ProQuest. For microform availability, contact ProQuest at 800-521-0600 or +1.734-761-4700, or search the Serials in Microform listings at POSTMASTER: Send address changes to Concrete Products, P.O. Box 1337, Skokie, IL 60076. REPRINTS: Mining Media Inc, 8751 East Hampden Avenue, Suite B1, Denver, CO 80231 USA; P: +1.303.283.0640, F: 1+303.283.0641, PHOTOCOPIES: Authorization to photocopy articles for internal corporate, personal, or instructional use may be obtained from the Copyright Clearance Center (CCC) at +1.978.750.8400. To obtain further information, visit COPYRIGHT 2014: Concrete Products ALL RIGHTS RESERVED 4 • August 2014 For the third year in a row, we visit a pavement project VCNA Prairie Material helped convert from all asphalt to partial (base slab) or 100-percent roller compacted con- crete. More than a routine switch, the Maryhill Cemetery maintenance shop (pages 28-31) marks the commercial debut of RCC Surface Pro, a silica agent emanating from the field of nanotechnology, where particles are measured in billionths of a meter. RCC Surface Pro is Lythic Solutions' latest nano-silica agent, joining a series of successful concrete polishing or slab-fnishing products of similar formulation. Nano-sil- ica is also referred to as colloidal silica, owing to the material's suspension within an "ultra-low surface tension liquid." Lythic tests fnd that a) colloidal silica reacts with lime formed during portland cement hydration, much like fy ash and other pozzolans; and, b) the lime imparts no structural value in a normal portland cement mixture, but in combination with colloidal silica promotes additional calcium silicate hydrate—the chief binding and strength- ening compound in concrete. The RCC Surface Pro demonstration at Maryhill yielded a troweled, broom-fn- ished slab. Instead of an RCC base placement one day, followed by asphalt wear course placement the next, the owner realized the economy of monolithic RCC fnished in hours. The project is the latest example of nano-scale materials' emerging role in concrete practice. A principal in New Jersey-based Intelligent Concrete LLC, Jon Belkowitz examines nano-silica admixture technology in "Colloidal Silica," a July 2014 Concrete International report: "The small CS [colloidal silica] particle can ac- celerate cement dissolution and nucleation as well as provide a much larger surface area of free silica for pozzolanic reaction. The CS admixture can thus provide rapid early-strength development and binding of the calcium hydroxide so that it does not participate in alkali silica reaction." Colloidal silica consists of ultra-pure silicon dioxide particles in a size range 1/1,000 that of Class F fy ash, he adds. Tested in a concrete mix with 20 percent ASTM C618 material, a colloidal silica admixture shows the poten- tial to enhance fresh concrete properties; reduce high range water reducer and air-entraining agents; increase early and 28-day compressive strengths as measured against control specimens; and, allow a reduction in cement content while maintaining target, hardened-concrete properties. A chart accompany- ing the Belkowitz article paints tested materials' reactivity potential through jaw-dropping differences in fneness (m 2 /kg): Type I/II portland cement, 392; Class F fy ash, 420; nano-silica, 500,000. Observation of 5-nanometer silica and other atomic-scale subjects is part of the Concrete Science program at the Massachusetts Institute of Technol- ogy-hosted Concrete Sustainability Hub. Researchers have recently outlined the potential for "Gorilla Cement," a nod to the thin, high strength Gorilla Glass that Corning Inc. has parlayed for smartphone, mobile device and laptop screens the world over. Viewing cement at the nano-scale, CSHub investiga- tors aim to pinpoint clinker phase chemistry changes netting higher silica content in calcium silicate hydrate. The effect would likely parallel concrete performance characteristics observed with colloidal silica admixtures or slab fnishing agents. Gorilla Cement research stands to beneft from the recently announced MIT.nano, a 200,000-sq.-ft. facility supporting research with nano-scale ma- terials and processes. "The tools of nanotechnology will play a critical part in how many engineering disciplines solve the problems of the 21st century, and MIT.nano will shape the Institute's role in these advances," says MIT School of Engineering Dean Ian Waitz. Whether they emanate from Cambridge, Mass., or companies like Vancou- ver, Wash.-based Lythic Solutions, nano-scale materials are sure to extend the value proposition of concrete in the decades ahead. Sizing up nano-scale materials

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