Better Roads

Better Roads February 2014 5 RoadScience by Tom Kuennen, Contributing Editor I nnovative materials for road and bridge construc- tion will be exhibited at ConExpo-Con/Agg 2014 in March in Las Vegas, and many of them are worth close examination for the exceptional engineering that distinguishes them. Last month, Road Science scrutinized noteworthy road con- struction equipment technology at ConExpo-Con/Agg. In this issue we look at the science and technology of select road construction materials to be exhibited at the show, all of which are proprietary products. Plan now to attend ConExpo-Con/Agg 2014 in Las Vegas March 4-8. Visit conexpoconagg.com for more information. Fiberglass strand grid for pavements An engineered pavement grid system has the ability to prolong pavement life while permitting higher loads with thinner asphalt lifts, according to the manufacturer Tensar International Corp. (booth No. 64927 in the Technology & Construction Solutions pavilion in South Hall 2). The GlasGrid pavement reinforcement system is composed of fi berglass strands coated with an elastomeric polymer and formed into a grid structure. Each strand has a high tensile strength and high modulus of elasticity; that's important be- cause asphalt concrete typically cracks at low strains. Fatigue and refl ective cracking in pavements generally are caused by traffi c loading, age hardening or temperature cycling. When cracking is present, the traditional remedy has been to apply thicker asphalt overlays. For each inch of applied overlay, existing cracks are generally deterred from refl ecting to the surface for a period of one year. When the GlasGrid system is sandwiched between the leveling course and the surface course in an asphalt overlay, it strengthens the pavement, turning vertical crack stresses horizontally to dissipate them. This once every-three-years trade show boasts innovative materials that deserve a closer look. Materials that Make a Difference On mill-and-fi ll project on busy Florida A1A/528 on Merritt Island, Trackless Tack from Blacklidge Emulsions is placed in advance of overlay. Photo courtesy of Tom Kuennen

• Cover
• ROAD SCIENCE: Materials that Make a Difference- Here's a sneak peak at the materials behind exceptional equipment for roadbuilding at ConExpo-Con / Agg 2014. Plus web exclusive coverage: a new generation of synthetic fibers.
• BETTER Bridges: Bridging the Gap Between Economics and Innovation- The Jesup Bridge in Buchanan County, Iowa, has been a vital market link for farmers and the community since it opened in the 1940s. When it became a safety hazard, the county knew it had t
• HIGHWAY CONTRACTOR: Running Shingles the Right Way: Running recycled asphalt singles and reclaimed asphalt pavement at the same can be tricky business. Here is what you need to know about heat transfer for good mixing.
• Transportation Talk: How an extra penny tax on every dollar will fund a South Carolina county's transportation system.
• In Court: The government denies a bid regarding a contract award to the second-lowest bidder based on a "best value' determination.
• The Last Word: Winter weather war stories, a truck of ice and a cool minivan "swagger wagon."
• Advertiser Index
• Marketplace
• New Road Products