INVESTIGATION OF RECYCLED TIRE CHIPS FOR USE IN GDOT CONCRETE USED TO CONSTRUCT BARRIER WALLS AND OTHER APPLIATIONS\u2013PHASE I

2017PDFTech ReportFHWA-GA-15-14RP 15-14Crumb rubberRecycled materialsTiresConcrete constructionWallsBarriers (Roads)Recycled materialsconcretetire derived aggregatestire chipscrumb rubberrubberized concreterubber modified concreteGeorgiaUnited StatesGeorgia. Dept. of Transportation. Office of ResearchDurham, Stephan A.Geum Chorzepa, MiStallings, KatelynUniversity of Georgia. College of EngineeringGeorgia. Dept. of Transportation. Office of ResearchUnited States. Federal Highway AdministrationUS Transportation CollectionIn 2013, GDOT constructed more than 42,000 LF of concrete barrier utilizing a Class A concrete mixture design (3000 psi). There may be potential for the beneficial utilization of recycled tire chips in concrete barrier applications which can possibly lead to improved safety for vehicle occupants as well as reduce disposed rubber from going to landfills or stockpiles, and potentially saving materials cost for GDOT. This study investigates the use of the recycled rubber tire chips as a replacement of natural aggregates in concrete mixtures. Fresh concrete properties in addition to concrete compressive strengths were investigated in this study. A coarse and fine aggregate size rubber particle were evaluated in this study: 3/4-in. tire chips and 30-mesh crumb rubber. The tire chips were used to replace coarse aggregates, while the crumb rubber was used to replace fine aggregate in the concrete mixtures in increments of 10% by volume. Results determined that concrete strength reduction was reduced with a fine aggregate replacement with crumb rubber as opposed to greater losses of strength exhibited by a coarse aggregate replacement with tire chips. Adequate strengths were achieved at replacement levels as high as 40% by volume with the crumb rubber. For the tire chips, satisfactory strengths were achieved with only a 10% replacement of coarse aggregates without surface pretreatement; however, higher strengths were realized by soaking the recycled tire chips in sodium hydroxide prior to batching. Slump and unit weight generally decreased with the addition of rubber pieces while air content increased slightly with higher rubber contents. Although, the indirect splitting tensile strength, modulus of rupture, and modulus of elasticity values were lower than the control mixture, results were all within typical ranges.. Concrete mixtures with rubber contents up to 20% exhibited superior impact resistance when compared to the control. Based on the results of this study, larger-scale barrier wall testing incorporating rubber contents up to 20% should be performance. In addition, other applications for which this material may prove useful include the concrete glare protection section on top of barrier walls, concrete curb and raised medians