Precast Solutions - July/August 2008 - (Page 7)

WHAT DO SPECIFIERS AND PRODUCERS NEED TO KNOW ABOUT UHPC? BY SUE MCCRAVEN It is critical that U.S. specifiers and precast concrete producers reach a level of comfort in designing and fabricating with UHPC. This can be accomplished through increased knowledge of UHPC material properties and characteristics and through adapting the best production protocols. More important, perhaps, is for U.S. precast concrete producers and specifiers to understand and appreciate the potential market value of UHPC applications. Brad Carpenter Q.What do you recommend to those considering UHPC products? A. “There must be a marketing and sales strategy to identify customers’ needs that can be solved using UHPC,” stresses Zakariasen. “Specifiers and operations people need to discard most of the knowledge they gained through their experience with traditional concrete, as it does not apply to UHPC; in fact, it will be detrimental to the successful production of UHPC.” Experimenting with this material for production can be very benefits are truly needed.” If current needs are already met by conventional precast or cast-in-place concrete solutions that are less expensive, concedes Zakariasen, “UHPC is not likely to be cost effective.” PROS AND CONS OF WORKING WITH UHPC expensive, notes Carpenter. “UHPC is not for the faint-hearted,” he says. Q.What are UHPC’s advantages and drawbacks based on your experience? A. “The learning curve for UHPC is substantial,” reports Brad Carpenter, CEO of Solus Décor in Vancouver, British Columbia. It takes about two years (including testing of production techniques and product prototypes) to get to a commercial product. The precast concrete producer must understand that there is a big difference between ultra high-performance and high-performance concrete. Q.Besides bridges and decks, what other products can take advantage of UHPC? A. “I believe there is untapped money-making potential for UHPC in the commercial and residential countertop market,” suggests Carpenter, “because the material can be produced in beautiful architectural sections as thin as three-fourths inch and 10 feet long and at prices that compete with conventional materials.” “The producer must learn new bin requirements, how to dispense the material within the mold, how to get it out of the bin fast enough,” explains Carpenter, “and UHPC is very expensive. From our perspective it is about seven times the cost of conventional concrete when you include the cost of our initial experimentation with the raw material.” “Water treatment, electrical transmission poles, security fencing around transformer stations, and building cladding are excellent applications of UHPC,” says Zakariasen. “Building cladding includes architectural panels that have advantages in seismic applications due their lighter mass.” Railroad ties, hollow-core slabs, pipe, protection panels (impact/blast UHPC’s advantage was the ability to “create a product line that required UHPC. In our case,” says Carpenter, “this was producing architectural precast benches for a municipality.” The attractive and durable benches produced by Solus Décor provide extremely high performance with freezethaw resistance down to -50 C (-58 F) and expectations for a long service life. Only UHPC could provide the exceptional durability demanded by the municipal client. Q.Any advice for the specifying engineer? A. Zakariasen notes that “The specifying engineer needs to understand UHPC’s material properties as well as the production limitations. Engineers Don Zakariasen, director of marketing, Lafarge North America, agrees with Carpenter’s assessment: “It is possible to provide new solutions to challenges that regular precast concrete is unable to meet. UHPC’s sales and marketing strategy requires the precaster to sell solutions rather than just concrete products. The benefits of UHPC offset the material costs in applications where the Don Zakariasen Sue McCraven, NPCA senior technical consultant, is a civil engineer, technical writer and editor, and environmental scientist who has contributed numerous articles and studies to prominent scientific journals. can reference design codes from other jurisdictions with more UHPC experience, or they may need to validate UHPC performance in testing by an independent accredited agency.” resistant surfaces), public architectural amenities, acoustical and structural wall panels, and up-scale residential designs (staircases, countertops, furniture) are other applications viewed for potential UHPC technology by researchers, designers, manufacturers and military technicians. JULY/AUGUST 2008 | PRECAST SOLUTIONS 7

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Precast Solutions - July/August 2008 Contents What You Should Know About UHPC A Winning Hand Fresno Federal Expanding U.S. Wind Power Precast Concrete Pipe

Precast Solutions - July/August 2008

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