Investigation of The Effects of Compaction Temperature on Properties of Hot Mix Asphalt

Abstract

Hot Mix Asphalt (HMA) pavement is designed to support the traffic load for 10 to 20 years and researchers have always paid the quality control of constructed roads with HMA due attention. Improper road works practices have been identified as the leading causes of poor performance of asphalt pavements, particularly for the dense-graded mixture. The selection of poor quality material may affect the overall performance of the pavement, including stiffness, stability, durability, workability, fatigue resistance, frictional resistance and resistance to moisture damage. In this study, considering the necessity of preserving the compaction temperature, the effect of various temperatures on Hot Mix Asphalt (HMA) samples properties has been evaluated. To evaluate the impact of this parameter on different grading, two different grading (Topcoat index grading and binder index grading) were used, and samples were compacted at 9(nine) various temperatures. Different Studies discussed the effect of compaction temperature on HMA properties and found a significant impact on the performance of asphalt concrete pavement. However, this study intended to investigate the effects of compaction temperature on properties of HMA tested at different compaction temperatures. The impact of compaction temperature on properties of hot mix asphalt has been studied at different compaction temperatures starting from 90 ºC to 170 ºC in 10ºC difference in laboratory. The difference has been studied concerning the standard Marshall Mix design preparation procedure. The test result shows that temperature does have an effect on the compaction asphalt and on the performance of the paved asphalt road. Thus this thesis presents the statement of the problem, objectives, literature review, test methodology of Design Analysis and evaluation of the effects of temperature on the hot mix asphalt by the most commonly used Hot Mix Asphalt Concrete Mix Design Methods used in Ethiopian Highway Roads. Fifteen (15) Marshall Specimens were used to select design gradation and optimum bitumen content based on maximum stability. Based on the Marshall Mix design, Forty-five (45) specimens were produced from three BRZs of gradation (BRZ4, BRZ5, & BRZ6) using the 0.45 power chart. The design gradation obtained to be BRZ5 with was 4.68%, 5.33%, and 5% OBC for gradation 5%, 6% and 7% filler proportion respectively with corresponding values 9.15 KN, 3.21 mm, 2525 kg/m3, 3.53%, 15.58%, and 67.4% of stability, flow, Unit weight, Va, VMA, and VFA respectively. It would be strongly recommended that the optimum allowable temperature for compaction must not be less than 150⁰C for laboratory uses. The test showed satisfactory results.