Concrete-Barriers or Road-Barriers Re-Designed with Fiber Reinforced Crumb Rubber Concrete

Increasing volumes of waster tires create environmental concerns for countries arund the wold. Disposing the tires as crumb rubber in construction materials is one alternative sought after by researchers. While this alternative is easily achieved, a challenge in producing a producing a product that provides benefits in performance and specific engineering applications is higly deisrable.The state of Arizona is well known for the use of recycled waste tire rubber (crumb rubber) in asphalt rubber hot mix. In the pas three years work between the Arizona Department of Transportation (ADOT) and ASU was extended to evaluate the use of fibers and curb rubber usage in Portland Cement Concrete (PCC) mixes for civilan development related projects. Examples are: roadway intersections, sidewalks, recreational courts and pathways, and wheel chair ramps for better skid resistance. These efforts have been recetly documented and recognized by the scientific community through a Journal article published at the Transportation Research Board in January 2005.The distributed rubber crumbs functions as mini expansion/control joints inside the concrete. It also provides a light weight advantage. The fibers act as a reinforcement and increase strength while allowing for a lighter weight product. Thus, the combined fiber reinforced crumb rubber concrete may exhibit good characteristics in controlling crack initiation, propagation and most importantly, reduce impact energy.Several Crumb Rubber in Concrete (CRC) test sections were built through out the state and are being monitored for performance as documented in the above referenced article. Laboratorey tests were conducted at ASU to support the knowledge learned in the field. These preliminary results were very encourageing and some of the perceived advantages are summariezed as follows:-Resistance against cracking-Reduces thermal expansion and contraction-Less drying shrinkage-Less susceptible to freeze thaw damage-Light weight-Improved skid properties-Noise reduction