High Performance Concrete Durability Center

For the past two years the New Hampshire Department of Transportation (NHDOT), the Federal Highway Administration (FHWA), and the University of New Hampshire (UNH) have been involved in research of High Performance Concrete (HPC). The research has consisted of building a bridge along route 102 in Bristol, NH utilizing HPC in the construction. Since then, the bridge has been monitored to see how well it stood up to New Hampshire conditions such as: freeze/thaw cycles and the blades of the plow trucks.

The effectiveness of HPC is measured because it enables bridge engineers to design more cost-effective bridges that will sustain a longer service life. HPC is defined as higher-durability and/or higher-strength concrete. "Durability" in this case includes four long-term performance characteristics: scaling, abrasion, freeze/thaw, and permeability resistance. Strength includes overall strength, modulus of elasticity, creep, and shrinkage. HPC is intended to lower initial cost and extend service life.

The use of higher-strength concrete enables bridge designers to build longer bridges, eliminating piers; and build bridges with wider girder spacing, potentially eliminating girder lines. Last month, over two hundred people attended the High Performance Concrete Bridge Showcase in Waterville Valley. The Showcase was held in cooperation with the NHDOT, FHWA, and UNH. The event brought in people from the federal, state, local, academic, and private sectors.

The two-day showcase featured over twenty speakers from various states' DOT's, universities, engineering firms, private industry, and FHWA. There were workshops on Mix Proportioning/Materials Testing and Structural Design and Fabrication /Construction. Vendors displayed their newest technologies and provided informative materials. The FHWA displayed the biggest attraction of the outdoor exhibits, their Concrete Testing Trailer.

The trailer contained many interesting pieces of testing equipment. The devices performed compression tests, rapid chloride tests, freeze/thaw durability tests, alkali-silica reactivity tests, and non-destructive tests. Also, on display were a maturity meter, which measures concrete strength and maturity in the field; and a microscope that measures air entrainment. The showcase concluded with a trip to Bristol to visit the NH Route 104 Bridge.