This report is an evaluation of the production of asphalic concrete by plants which employed the drum mixing method. The production of mixes are traced through the entire system from the stockpile to the road with respect to quality and adherence to specifications. The operation of the plant's main components, problems encountered and remedial action taken are fully discussed in this report. The results of this study have shown that the asphalt cement coating of the aggregate has been good and no stripping of this coating has occurred in mixes placed two years ago. The minimum placing temperature of these mixes was found to be 240 deg F and the very small moisture residue has not had any beneficial or detrimental effect on the compaction of the mix at the road. The variation of the asphalt cement contents and the retained #4 material are slightly higher in mixes produced by the drum mixer when compared to the conventional type plants. The drum mix plants have many definite advantages such as lower initial cost, elimination of high maintenance components, are highly portable, employ lower mixing temperatures and have high production rates that make this construction method highly competitive and have reflected in lower bid prices and monetary savings to the Ministry. This report recommends changes in the drum mix plant that should provide greater accuracy in the moisture sensing probes, temperature sensing probe and asphalt cement delivery system. The large daily tonnages of mix produced by the drum plants have indicated to the Ministry the need for improved field testing of the mix. Since the drum plants operate without screens, the aggregate production and stockpiling should be closely controlled and the accuracy of the aggregate stockpiles should be of greater concern to the contractor. It is concluded based on three years of study taht the drum mix plant is capable of producing highly competitive and cost effective asphaltic concrete mixes that compare with those mixes produced by the conventional type asphalt plants.

  • Corporate Authors:

    Ontario Ministry of Transportation & Communic, Can

    Quality Assurance Section, 1201 Wilson Avenue
    Downsview, ONo M3M 1J8,   Canada 
  • Publication Date: 1978-1

Media Info

  • Features: Appendices; Figures; References;
  • Pagination: 105 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00335521
  • Record Type: Publication
  • Report/Paper Numbers: EM-18
  • Files: TRIS
  • Created Date: Nov 23 1981 12:00AM