Date of Graduation

Spring 2016

Document Type

Honors Research Project

Degree Name

Bachelor of Arts

Major

Geology - Environmental Science Track

Research Sponsor

Dr. Caleb W. Holyoke, III and Dr. Ala R. Abbas

First Reader

Dr. Adil Wadia

Second Reader

Dr. Alamgir Karim

Abstract

This research paper explores the benefits of using rubberized asphalt concrete (RAC) versus normal asphalt concrete (NAC) and why it is environmentally important. New road construction and repair of roadways due to potholes are always occurring in Northeast Ohio. Recently, the city of Akron’s transportation budget has increased, which includes projects such as reconstructing asphalt and resurfacing pavements throughout the city of Akron. Using rubberized asphalt may improve the quality of our roads and reduce roadway degradation which will likely save cities money.

Using rubberized asphalt recycles old tires, which do not decompose, and creates a positive use for them when normally they would be disposed of in landfills and illegal stockpiles. RAC is possibly more effective than NAC for roadways in Northeast Ohio’s climate due to the increased stiffness at cold temperatures and increased elasticity at warmer temperatures caused by the ground tire rubber additive to the binder. To test which type of asphalt, RAC or NAC, will perform at a higher quality, various Indirect Tensile (IDT) tests were performed to compare the ultimate tensile strengths of RAC & NAC at three temperatures.

Rubberized and normal asphalt cores were manufactured by mixing warm (135°C) binder and aggregate and then compacting this mixture to a low porosity in a mold. After compaction, these cylinders cured at room temperature for at least 48 hours. The cylinders were sliced perpendicular to their length to make short cylinders with a height which is approximately half of the diameter of the cylinder. Strength testing was performed according to AASHTO method T 322-03 (indirect tension test or IDT) using an 810 Material Test System located in the Civil Engineering Department at the University of Akron. Strength tests were performed at three temperatures which exceeds the natural range of temperatures in northeast Ohio (-75°C, 0°C, and 25°C). The results from the IDT testing demonstrates that adding ground tire rubber to asphalt increases the stiffness, maximum load capacity, and calculated strength when compared to regular asphalt.

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