Hot Mix Asphalt (HMA) design has undergone years of development. Currently, many state agencies use the Superpave mix design method. While the Superpave mix design improved rutting, the implemented level 1 only considered volumetric properties and not mixture performance tests. Therefore, development in the asphalt community has addressed some of the issues with the Superpave mix design, e.g., cracking and raveling, with the Balance Mix Design (BMD) approaches. The Balance Mix Design incorporates performance testing elements that the level 1 Superpave mix design does not.
The Virginia Department of Transportation (VDOT) aims to implement the Balance Mix Design by 2023. The objective of this thesis is to evaluate the initial frictional properties of mixes designed using the Balanced Mix Design method to verify that safety is not compromised to support the implementation of the BMD method within VDOT. It provides a further understanding of BMD mixtures surface properties provides insight into volumetric properties that may influence macrotexture.
The thesis analyzed the initial friction and macrotexture of a series of experimental sections built to support VDOT BMD implementation efforts. A Side-Force Coefficient Road Investigation Machine (SCRIM) was used to measure friction and texture data on Control (Superpave Mix Design) and Balance Mix Design sections on several VDOT districts. Once the data was collected, it was analyzed using descriptive statistics and mean comparisons to determine any statistical differences in the friction and texture of the Control and BMD Mixes. The analysis showed that although statistically significant differences in friction and macrotexture were observed between some of the Superpave (Control) and Balance Mix Design mixes, the differences seem to be more prominent among districts than between the mix design method. In general, there were no difference in friction between control and BMD mixes in the same locations. On the other hand, there is statistically significant differences in the as-constructed macrotexture of Superpave and BMD mixes evaluated, with more BMD mixes having higher macrotexture than their control counterparts.
Further analysis was conducted to create a macrotexture prediction model based on production volumetric properties obtained from VDOT databases. The model provided an initial assessment of the main HMA properties that influence MPD. A comparison of the macrotexture of the constructed in the various locations found that there is strong statistical evidence that the mean macrotexture of the pavement constructed in the various location was different. The analysis also showed that some projects produced sections with more uniform macrotexture than others. Comparison of mixes constructed in different years does not suggest any significant differences over the three-construction season evaluated. / Master of Science / Hot Mix Asphalt (HMA) is derived from various mix designs over the last hundred years. Currently, many highway agencies use the Superpave Mix Design in roadway development but only his basic level has been implemented. Most agencies do not use mechanical tests to verify that the mixes will perform properly when place on the pavement. To address some of issues with the current mix design approach, highway agencies have started to implement and use the Balance Mix Design (BMD). The Balance Mix Design incorporates performance tests for distresses such as rutting and cracking where the Superpave Mix Design did not.
The Virginia Department of Transportation (VDOT) is working towards implementing the Balance Mix Design by 2023. The objective of this thesis is to evaluate the initial frictional properties of mixes designed using the Balanced Mix Design method to verify that safety is not compromised to support the implementation of the BMD method within VDOT. It helps agencies understand of BMD mixtures surface properties and what mix design properties may influence the safety of the road surface.
The thesis analyzed the initial friction and macrotexture, properties that allow the vehicles to break and maintain control on curves, of a series of experimental sections built to support VDOT BMD implementation efforts. The Side-Force Coefficient Road Investigation Machine (SCRIM) is a large vehicle that continuously measures the pavement surface for friction, texture, and other elements using a skewed wheel and a laser system. The SCRIM was used in this thesis to measure friction and texture data on Control (Superpave Mix Design) and Balance Mix Design sections constructed on several VDOT districts. The data were analyzed using statistical analysis to determine any differences in the friction and texture of the Control and BMD Mixes.
In general, there are no differences in friction between control and BMD mixes in the same locations. On the other hand, the analysis showed significant differences in the as-constructed macrotexture of Superpave and BMD mixes evaluated. In general, more BMD mixes had higher macrotexture than their control counterparts. Further analysis was conducted to create a macrotexture prediction model based on production volumetric properties obtained from VDOT databases. A comparison of the macrotexture of the constructed in the various locations found that there is strong statistical evidence that the average macrotexture of the pavement constructed in the various location was different.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/111435 |
| Date | 02 August 2022 |
| Creators | Matics, Janie Katherine |
| Contributors | Civil and Environmental Engineering, Flintsch, Gerardo W., Heaslip, Kevin Patrick, Katicha, Samer Wehbe |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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