Jordan Journal of Civil Engineering, Volume 9, No. 3, 2015 - 400 - © 2015 JUST. All Rights Reserved. Using Waste Tire Crumb Rubber As an Alternative Aggregate for Concrete Pedestrian Blocks Khaldoon A. Bani-Hani 1) and Ahmed Senouci 2) 1) Department of Civil Engineering, Jordan University of Science and Technology, P.O. Box 3030, Irbid-22110, Jordan. 2) Department of Construction Management, University of Houston, Houston, TX 77204-4020, Texas, USA ABSTRACT This study investigates the performance of using waste tire crumb rubber as an alternative aggregate for concrete pedestrian blocks. It focuses on determining the engineering properties of the crumb rubber concrete pedestrian blocks, such as unit weight, water absorption, compressive and flexural strengths, as well as freeze-and-thaw resistance. Crumb rubber has been previously used in several applications, such as asphalt pavement, waterproofing systems, membrane liners,… etc. In this study, crumb rubber is used to replace portions of fine aggregates in the manufacturing of concrete pedestrian blocks. Crumb rubber concrete pedestrian blocks were found to possess good aesthetics and a smaller unit weight than plain concrete pedestrian blocks. They were also found to have good resistance to repeated freezing and thawing cycles. However, crumb rubber concrete pedestrian blocks exhibited low compressive and flexural strengths. Unlike plain concrete pedestrian blocks, crumb rubber concrete blocks did not demonstrate the typical brittle failure. They exhibited a ductile, plastic failure and showed the ability to absorb a large amount of plastic energy under compressive and flexural loads. KEYWORDS: Pedestrian block, Rubber crumb, Concrete, Compressive strength, Flexural strength, Freeze-and-thaw resistance. INTRODUCTION Recycling discarded automobile tires has become an increasingly important issue, since the disposal of used tires has been banned from landfills. As a consequence of this ban and the lack of an alternative technology to dispose of large quantities of used tires, there are millions of used tires stockpiled, some illegally. The growing stockpiles of discarded tires represent potential fire and health hazards. Recycling waste tire rubber conserves valuable natural resources and reduces the amount of waste entering landfills. The main method of recycling these waste materials has consisted of using tire rubber particles as coarse or fine aggregate in concrete. Results indicate that rubberized concrete mixtures possess lower density, increased toughness and ductility, lower compressive and tensile strengths and more efficient sound insulation (Siddique et al., 2008). Raghavan et al. (1998) reported that mortars incorporating rubber shreds achieved workability comparable to or better than a control mortar without rubber particles. Because of the low specific gravity of rubber particles, the unit weight of the mixture containing rubber decreases with the increase in the rubber content. They also observed that rubber shreds incorporated into mortar help reduce plastic shrinkage cracking in comparison to control mortar. Eldin and Senouci (1993) studied the mechanical behavior of concrete containing rubber tires and showed that the Accepted for Publication on 23/4/2015.