EVALUATION OF BAGHOUSE FINES IN BITUMINOUS PAVING MIXTURES

Nine baghouse fines representing diffeent generic types (such as, trap rock, gneiss, carbonate, slag, sand and gravel, sandstone, etc.) were sampled from operating asphalt plants in Pennsylvania and evaluated in this study. Portland cement was used as a control mineral filler. This research was undertaken to achieve the following objectives: (1) to characterize various generic types of baghouse fines by their physical and chemical properties; (2) to determine the effect of baghouse fines on the physical properties of fines-asphalt (F/A) binder system; (3) to determine the effect of baghouse fines on the physical properties of dense-graded asphaltic concrete; (4) to determine the detrimental effects, if any, of the baghouse fines on the mix resistance to damage by moisture; and (5) to develop a suitable specification for the highway departments to insure qualitative and quantitative control of the baghouse fines incorporated into the mix. The data obtained in this study indicated the following: (1) Some baghouse fines (such as, trap rock, gneiss, sand and gravel) have a tremendous stiffening effect on fines-asphalt systems which offer resistance to compaction. Bulk volume concentration of fines (VfB) has been determined to be the primary factor causing the stiffening; (2) limiting values of viscosity ratio and change in softening point of fines-asphalt systems have been developed from the bulk volume of fines values to keep the stiffening effect within desirable limits; (3) some baghouse fines (three slags and one carbonate) were determined to be detrimental to the mix making it susceptible to moisture damage. Field case histories of the use of three baghouse fines are given. Suitable specifications for the quantitative and qualitative control of the baghouse fines have been developed and suggested for use by the highway departments to insure reasonable pavement performance and durability. It has been recommended that a positive feed system to reintroduce the baghouse fines uniformly into the mix should be made mandatory.

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 129 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00331086
  • Record Type: Publication
  • Report/Paper Numbers: Project No. 79-23
  • Files: TRIS, STATEDOT
  • Created Date: Oct 28 1981 12:00AM