Evaluation of field performance of fine-graded hot mix asphalt on Illinois' roadways

Fine-Graded Asphalt;Hot-mix asphalt;Quality Assurance;Quality Control;Pay-For-Performance

Castro, Brian ; Buttlar ; William G.

关键词: Fine-Graded Asphalt;    Hot-mix asphalt;    Quality Assurance;    Quality Control;    Pay-For-Performance;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/49422/Brian_Castro.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Coarse-Graded Hot Mix asphalt has been utilized as the standard mix for asphalt projects across transportation agencies. Primarily, this was due to the idea that that a coarser gradation could be more rut resistant than a fine-graded mix. Fine-graded mixes were determined to be tender mixes due to the inclusion of natural sand as the main fine aggregate. However, manufactured sand, which has a higher angularity than natural sand, is the main fine aggregate utilized in hot mix asphalt at this time. Manufactured sand, which is produced from crushed aggregate, is more rut resistant than natural sand.Laboratory experiments have taken place over the past decade between the comparison of coarse graded hot mix asphalt and fine graded hot mix asphalt. Rutting, permeability, fracture energy, segregation and tensile strength were among the properties tested in order to compare CG HMA and FG HMA. Accelerated pavement testing also took place in order to compare both FG HMA and CG HMA. In all performance tests, FG HMA performed either equal or better than CG HMA.Among the concerns that transportation agencies have stated about CG HMA are its propensity to segregate, its difficulty to compact and achieve consistent high density, high permeability and below-standard pavement long term performance. The IDOT Pay-for-Performance QC/QA standard evaluates the asphalt mixes depending on its ability to achieve consistent volumetric characteristics. The lower the standard deviation for density tests, air voids content and VMA is, the better performing the mix is and the higher are the contractor’s chances to obtain a bonus. If the FG HMA mix is more consistent than CG HMA, then it could become the standard mix per standard specifications. This thesis investigated two case studies where IDOT PFP was employed as the QC/QA standard and where FG HMA was put in place and evaluated per IDOT PFP.This mix that was evaluated with IDOT PFP was the IL-19.0 mm FG, which is the fine-graded variation of the traditional IL-19.0 mm. The projects that served as case studies for this thesis were located on I-57 on Champaign, IL and on I-39 at Bloomington, IL. The analysis concluded that the IL-19.0 mm performed above standard per IDOT PFP on the project at I-57 and on the project at I-39. Different binder types were utilized on the mixes put in place on both projects but the was no significant difference between the pay factors of FG HMA mix with unmodified binder and FG HMA mix with polymerized binder. The long term pavement performance of FG HMA on Illinois’ roadways is to be determined.