Thermal expansion
Concrete’s volume change due to temperature change is not normally a significant issue for concrete in a building, but it can be in pavement. To evaluate the expected volume change, Pine Instrument Co. has developed a device, the AFCT2, for determining the Coefficient of Thermal Expansion (CTE) of concrete samples. This device can vary the temperature of a concrete core sample from 10°C to 50°C and requires minimal operator involvement with the test. This company also got a grant from the Federal Highway Administration (see below) to develop the Aggregate Image Measurement System that analyzes aggregate angularity, form, and surface texture—characteristics that can affect pavement durability and performance.
Emerging technology
The Federal Highway Administration (FHWA) has an active program to promote the development and use of new technology. As described by Julie Zirlin in an article in Innovation, America’s Journal of Technology Commercialization, the FHWA’s Technology Partnership Program, part of the Highways for Life program, awards grants to highway agencies to accelerate the adoption of “late-stage prototypes.” This is intended to push innovative materials and techniques that last little step from viable to proven. In 2011, this program awarded $19 million, including $420,000 to the Arkansas State Highway and Transportation Department for a heavy-duty roller-compacted concrete overlay.
Solid sludge
Sludge at a ready-mix plant can create real problems, especially on small-footprint sites. Fortrans Sludge Set is a granular, super-absorbent drying agent that can absorb up to 250 times its own weight in water, quickly drying sludge and allowing its offsite disposal. Unlike other drying agents, Sludge Set adds less than 1% free swell, which lowers transportation costs. Fortrans also has developed complete water and sludge handling systems that include pH control to allow the use of pH-adjusted water for discharge or as process water to batch concrete.
