Better Roads

February 2014

Better Roads Digital Magazine

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Better Roads February 2014 9 drainage pipe applications, while competing geocomposite cores are made from less desirable materials, such as low den- sity polyethylene or styrene, ADS says. "Rigid pipe transmits most of the load through the pipe wall into the bedding. In both cases, proper backfi ll is very important in allowing this load transfer to occur," ADS says. "The number one characteristic that sets HDPE apart from other pipe types is that it can be made to be fl exible. This quality opens HDPE pipe up to a different world of applica- tions than rigid pipe." Initially, lightweight HDPE pipe is less expensive than RCP and can be handled with less fuss, but the concrete pipe industry says it's more dependent on careful installation of bedding, while strong, rigid concrete pipe is more forgiving. Viscoelasticity is the property of materials that exhibit both viscous and elastic characteristics when undergoing deforma- tion. Viscous materials resist shear fl ow and strain linearly with time when a stress is applied. Elastic materials strain when stretched and quickly return to their original state once the stress is removed. Viscoelastic ma- terials have elements of both of these properties and, as such, exhibit time- dependent strain. Tests show that polyethylene and polypropylene do not weaken through- out time, ADS says, adding that the same stress/strain curve for the material can be duplicated repeatedly. What remains unaccounted for in the test is stress relaxation, which is a property unique to viscoelastics. A popular engineered HDPE product is N-12 pipe from ADS, with perfor- mance advantages over traditional pipe at a fraction of the cost, the maker says. N-12 offers abrasion resistance and won't rust or corrode. It's used for cross drains, side drains, storm sewers, culverts, landfi lls and other installations across the country and is available in sizes from 4- to 60-inch diameters. The pipe's design can withstand H20 and E80 loads, making it suitable for culvert installations. As N-12 pipe is lightweight, it requires fewer people, less time, and less heavy equipment to install, ADS says. Due to the longer lay lengths, ease of handling, and push–together joints of ADS pipe, the installed cost savings of HDPE ranges from 10 to 30 percent when compared to reinforced concrete pipe, the fi rm says. In the meantime, a nationwide survey released in 2012 by the American Concrete Pipe Association found that concrete pipe rated highest on several of the criteria used to make deci- sions on such purchases. Among specifi ers, Department of Transportation/public agency offi cials, and consultants, concrete pipe was rated best among all pipe products on several key criteria, includ- ing most durable (87.3 percent), easiest to design or specify (62.1 percent), least fl ammable (84.1 percent), least instal- lation inspection required (54.5 percent), least installation sensitive (62.1 percent), and "greenest" (34.1 percent). When asked, "If price were not an issue, which pipe would you specify?" 84.6 percent chose concrete pipe. A different-function engineered product is ADS AdvanEDGE RoadScience 7H[W,1)2WRRUYLVLWZZZEHWWHUURDGVFRPLQIR Cut foremen entry time in half with HeavyJob Mobile Apps and... Reduce payroll processing by as much as 90% <ŶŽǁŝĨũŽďƐĂƌĞƉƌŽĮƚĂďůĞǁŝƚŚƐĂŵĞͲĚĂLJ ĨĞĞĚďĂĐŬĂŐĂŝŶƐƚďƵĚŐĞƚ tŽƌŬŽŋŝŶĞĨŽƌƌĞŵŽƚĞũŽďƐǁŝƚŚŶŽŝŶƚĞƌŶĞƚ dƌĂŝŶĨŽƌĞŵĞŶƋƵŝĐŬůLJǁŝƚŚĞĂƐLJͲƚŽͲƵƐĞƟŵĞĐĂƌĚ >ŽǁƌŝƐŬͶ^ŽŌǁĂƌĞĐŽŵĞƐǁŝƚŚĂϭϮͲŵŽŶƚŚ ŵŽŶĞLJďĂĐŬŐƵĂƌĂŶƚĞĞ͊ S o u t h H a l l # 6 4 5 2 8 N o r t h H a l l # 1 1 9 5 6 at or 800-683-3196 Learn More

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