Asphalt Pavement Compaction Research Articles

Quality Assurance of Hot Mix Asphalt Pavements Using the Intelligent Asphalt Compaction Analyzer

Adequate compaction of asphalt pavements during their construction is essential to the long-term performance of the pavement. Current quality control techniques determine the quality at a limited number of points and are not indicative of the overall quality of the pavement. In this paper, the intelligent asphalt compaction analyzer (IACA) is used to estimate the density of an asphalt pavement during its construction and thereby determine the overall quality of compaction. A comparison of these estimates with the percent within limits (PWL) calculations based on roadway cores demonstrates that the IACA can be effectively used as a nondestructive quality assurance (QA) tool. Further, since the IACA continuously estimates the density of the asphalt in real time, inadequate compaction can be addressed during the construction, thereby improving the overall quality of pavement. Thus, the IACA can also serve as a valuable quality control (QC) tool during the construction.

Evaluation of Full-Depth Asphalt Pavement Construction Using X-Ray Computed Tomography and Ground Penetrating Radar

In the past few years, a number of full-depth or perpetual pavements have been designed and constructed in the State of Texas. A study was conducted to examine the quality of the compaction of the thick asphalt layers within these pavements using advanced forensic tools such as X-ray computed tomography (X-ray CT) and ground penetrating radar (GPR). The GPR is a nondestructive tool for evaluating the uniformity of density in pavements at highway speed. X-ray CT is a laboratory tool that is used to conduct detailed analysis of air void distribution and uniformity in asphalt pavement cores. This paper presents the results of analyzing one of the perpetual pavements constructed in State Highway 114 (SH-114). In this project, two different structural asphalt pavement sections were placed, one included a 1in. (25.4 mm) stone filled (SF) Superpave mix and the other included a traditional dense graded Type B material. The dense graded Type B material was found to be uniformly compacted. However, major compaction problems were identified with the coarse SF Superpave mix. The poor compaction and associated high percent air vsoids were found to permit moisture infiltration, which could potentially lead to rapid pavement deterioration. The analysis showed very good agreement between the GPR and X-ray CT results and demonstrated the efficiency of using GPR and X-ray CT in the evaluation of asphalt pavement compaction.

Effects of Temperature and Pressure on Hot Mixed Asphalt Compaction: Field and Laboratory Study

A field and laboratory study was carried out to study the effect of pressure and temperature on the compaction of asphalt pavements. Density, temperature, number of passes, and type of roller were recorded in the field at four different paving projects in Wisconsin, with binder and mixture samples obtained from each project. Compaction in the field occurred at temperatures that ranged from 125 to 60°C. Densification was achieved only for temperatures above the 70–80°C range. Roller contact pressures were estimated between 300 and 700kPa during the compaction process. Laboratory compaction was performed with Superpave gyratory compactor using the field compaction temperatures and contact pressures. The lab compaction results confirmed that below a certain temperature limit densification decreased significantly. Binder testing was performed to determine the binder viscosities in the full range of field compaction temperatures observed. The upper limit of viscosity for significant reduction in densification was estimated to be 50Pas. A procedure for identifying the lowest temperature at which acceptable densification rate can be achieved is proposed based on testing using the dynamic shear rheometer. The determination of the lower temperature limit for compaction is an important task that is absent in the current specifications.

Comparing Superpave Gyratory Compactor Data to Field Cores

Achieving proper compaction of asphalt pavement is crucial to its longevity and acceptable performance. Laboratory compaction is an essential part of mix design. In order for the mix design process to be effective, laboratory compaction must adequately simulate field compaction. This study used mechanical properties measured with the Superpave shear tester to evaluate field compaction and laboratory compaction. The field compaction consisted of three test sections with different compaction patterns. The laboratory compaction used the Superpave gyratory compactor with adjustments to several parameters. Results of this study indicate that current gyratory protocol produces specimens with significantly different mechanical properties than field cores produced with the same material and compacted to the same air voids. Results also show that adjustments to certain parameters of the gyratory can produce specimens that better simulate the mechanical properties of pavement cores.

AutoPave: towards an automated paving system for asphalt pavement compaction operations

Asphalt pavement density from roller compaction is a crucial factor in ensuring satisfactory pavement performance. Proper and uniform compaction of the pavement mat is essential in achieving the desired final compacted density. There is a necessity to investigate existing pavement construction practices, and provide more cost-effective modifications to the current scenario. Automation of the paving operation can increase the efficiency and quality of the operation, lead to reductions in overall project costs and time, and enhance pavement life. A system can be developed through algorithmic planning and real-time guidance strategies, and the development of a semi-automated path-planning and real-time guidance system that aims towards automating the paving operation. This system accepts relevant paving project inputs, generates appropriate path plans for the compactor, performs a graphical visualization of the generated path plan, and offers real-time guidance capabilities using Global Positioning Systems (GPS) technology. This system, named AUTOPAVE (v1.0), was developed in Microsoft Visual Basic™ programming language and offers a user-friendly and interactive graphical interface. The proposed new system will incorporate state-of-the-art GPS technology to standardize paving operations that are more amenable to rigorous quality control, and can result in considerable reductions in cost and time involved in asphalt pavement construction projects. This system was tested on several actual paving projects, and many operational issues related to the functioning of the system were successfully overcome.