College of Engineering

A master thesis was discussed in Department of Civil Engineering / College of Engineering at University of Mosul entitled “Some Engineering Properties of Stabilized Reclaimed Asphalt Concrete” submitted by (Israa Mohammed Mushtaq Saeed), Supervised By Prof. Dr. Suhail Adrees Abdulkader Khattabon Thursday, Aug. 25, 2022.The thesis presents the laboratory evaluation of concrete asphalt waste available in the city of Mosul and the possibility of using it in the construction of the base and sub base layer for roads. The study also touched on the possibility of developing uses by stabilizing these wastes by adding cement in different percentages (1,3,5,7)%, as well as adding bitumen emulsion paint at different rates (2.5, 3.5, 4.5)%. On the other hand, the study dealt with the evaluation of the durability of asphalt concrete waste stabilized with cement at a rate of (2,4)%. The most important variables that were taken into consideration were the percentages of materials (cement, bitumen emulsion paint) added, the effect of curing periods that lasted 28 days, the moisture content at which the models were compacted, to achieve these goals, many tests were conducted on concrete asphalt waste (moisture content, specific gravity, abrasion test, gradation, modified compaction, California bearing test, unconfined compression test, In direct tension strength).The results showed that the asphalt concrete samples have resistance against corrosion and found the possibility of using asphalt concrete waste provided that after adjusting the grading in the sub base construction, also found the possibility of using asphalt concrete waste stabilized with cement in the construction of the base layer. The value of the California bearing ratio also increased, and the unconfined compressive strength, which reached a maximum when using 7% cement and after a treatment period of 28 days. The study also concluded that it the value of tension strength is equal to 5% of the value of compressive strength of samples stabilized by 2% of cement.On the other hand, the study showed that was not possible to use asphalt concrete waste stabilized with bitumen emulsion paint in the construction of the base layer, as the compressive value of the stabilized samples was (2.5, 3.5, 4.5)% (0,5,5.3) kg /cm2, respectively, which are not acceptable according to the specification The Iraqi Roads and Bridges, The durability of asphalt concrete waste samples stabilize with cement ratios of (2,4)% was also studied, as it was found that these stabilize sample succeeded, as the weight loss for samples stabilize with cement after 12 cycle was at rates of (2,4)% (7.45,5.39)%, respectively, which are less than 8% and are acceptable according to the specification. Also, the residual compressive value of the at samples stabilized by 2% cement after 12 cycles of wetting and drying was 32.9 kg/cm2over 25 kg/cm2 is acceptable according to the specification The Iraqi Roads and Bridges, It was also found that the residual compressive strength of the samples stabilized by 4% cement was 54.53Kg/cm2over 25 kg/cm2 is acceptable according to the specification The Iraqi Roads and Bridges.Finally, The economic impact was also studied when using stabilized asphalt concrete waste in the construction of road layers and the extent of the possibility of reducing the construction cost. It was found that when using asphalt concrete waste stabilized with cement, the cost was significantly reduced. When using asphalt concrete waste stabilized with cement by 2%, the cost decreased by 65.82%, and when using asphalt concrete waste stabilized with cement by 4%, the cost decreased by 64.48 % of the total cost of constructing road layers when the use of natural materials.