IMPROVE THE WAXY ASHPALT CONCRETE MIXTURE PROPERTIES USING CRUMB RUBBER AS AN ADDITIVES

For more than half a century, asphalt cement used in Egyptian road construction was produced by distillation of crude oils from the fields in the Red Sea area. At the early seventies, the production from the Suez refinery was halted, and asphalt cement was produced from newly discovered crude oil fields in the Egyptian western desert. However, many problems were accompanied by severe creep deformations towards pavement edges and near the median curbs, and Pavement service life dropped from 15 years to about 3 years. This research had studied the effect of adding Crumb Rubber from recycled tires as additive in the mixture by rations 1%, 2%, 3%, 4%, and 5% to bitumen in the asphalt mixture to improve the performance of the waxy asphalt and compare the result with 3 control samples. The optimum bitumen content was determined using the Marshall method. The bitumen range region was set according to each mixture's bitumen demand. The relationship between traffic volume and stability describing the effect of applying the additive by varied ratios will be tabulated, as well as the flow, stability, and penetration values. Using Crumb Rubber from recycled tires as additive used in this study improved the waxy asphalt mixture properties and it is recommended to be used under heavy traffic loads as the marshal stability results show ascending increase from 1029 kg to 1252 kg by increasing the percentage of Crumb Rubber as additive from 1% to 5%. Also, it is recommended in warm weather as the penetration test results show increasing values from 2.96 mm to 3.025 mm and decrease in rutting wheel tracking test value reached 2.2 mm depth at 10000 total Passes. The results show a slight increase in flow values by increasing from 2.96 mm to 3.025 mm by increasing the percentage of Crumb Rubber as additive from 1% to 5% (4.5%) more than control sample at 5% Crumb Rubber as an additive to bitumen The results show a decrease in penetration value by increasing the percentage of the Crumb Rubber as additive from 1% to 5% as additive till reached 42 mm at 25°C. The results show a decrease in LWTR value reached 2.2 mm depth at 10000 total Passes.