INSIDE THE DOT
South Dakota Department of Transportation
Investigation of Anomalous Asphalt Concrete on US212
A research project "Heaves at Transverse Cracks in Asphalt Concrete Pavement" SD92-11 completed June 30, 1993 investigated the cause of heaves at transverse cracks on US Highway 212 (F0212(56)187) between LaPlant and the Missouri River. The project was paved using 50 percent natural aggregate and 50 percent salvage asphalt. This project manifested excessive transverse cracking immediately after construction and had a cracking rate of approximately 110 transverse cracks per mile approximately three years after construction. Core samples of this asphalt concrete were extracted using trichloroethane solvent. This asphalt appeared to have generated hydrogen chloride gas during extraction and caused severe corrosion of the copper extraction apparatus. The mineral aggregate remaining in the extraction apparatus was coated with charred asphaltic material. Five nearby projects built during the same period were also investigated, none of which exhibited the same extraction characteristics even though some of the asphalt came from the same sources. The anomalous behavior of this asphalt and a possible link between the transverse cracking and corrosion during extraction require additional research. There is a possibility that the phenomena observed may have been caused by the presence of a foreign material in the asphalt.
1 Identify the presence of any detrimental material present in the asphalt concrete.
2 Identify test methods that would detect or limit any extraneous materials in asphalt.
3 Develop recommendations on implementation of test methods, policies and procedures to identify and limit any extraneous materials in asphalt.
1 Meet with the Technical Panel to review the work and scheduling.
2 Review and summarize relevant literature concerning asphalt concretes exhibiting high crack frequencies and asphalt that may contain foreign substances and exhibit anomalous extraction properties.
3 Review project documentation and interview appropriate departmental personnel.
4 Conduct appropriate physical and chemical analyses on the pavement materials in question to determine what may have contributed to excess cracking in the asphalt from LaPlant to the Missouri River on US212.
5 Provide comparative testing on two nearby control projects from the previous research "Heaves at Transverse Cracks in Asphalt Concrete Pavement" SD92-11.
6 Based on the results of the physical and chemical analyses recommend test procedures that will identify asphalt exhibiting similar properties to those on US212 LaPlant to the Missouri River. The test procedures considered should include but not limit
7 Prepare a final report and executive summary of the literature review, research methodology, findings, conclusions, and recommendations.
8 Make an executive presentation to the SDDOT Research Review Board at conclusion of the project.
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