The origin of modern controls and the resulting variability was studied in an effort to develop a better understanding of control systems. Practices with sheet aspahlt in 1900 are mentioned and pavements built under patents issued to F.J. Warren are described; these include Bitulithic, Warrenite, Warrenite-Bitulithic, Topeka, and Black Bass. The quality control system used by Warren Brothers (illustrated by typical Bitulithic specification) controlled aggregate gradation, bitumen content, mixing coating, workability, overheating and compaction. Important requirements in which federal specifications differ from Warren specifications include the following: master ranges for aggregate gradation and asphalt content; job mix formula and tolerances, including mix temperature delivered to the job; temperature controls of bitumen aggregate, mixing, and mix at the plant; weather and limitations, detailed plant requirements; machine laydown; detailed roller and rolling requirements; and smoothness requirement. Variability by design is considered and variability in construction is discussed. Patented pavement, gradation and bitumen content, gradation, asphalt content and density of modern pavements are detailed. The limitation of variability is discussed. It is urged that controls should distinguish between satisfactory and unsatisfactory pavements. Satisfactory control can be maintained without excluding good construction and unnecessarily increasing costs. Controls should tailored to accommodate the characteristics of different mixtures, the requirements of the pavement, and the conditions encountered in construction. Either the conventional process control system or the newer end result specifications can be made to function satisfactorily for modern construction.

  • Supplemental Notes:
    • Proceedings of the meeting held in Houston, Texas, February 1973.
  • Corporate Authors:

    University of Minnesota, Minneapolis

    155 Experimental Engineering Building
    Minneapolis, MN  United States  55455
  • Authors:
    • Tunnicliff, D G
  • Conference:
  • Publication Date: 1973

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 440-481
  • Serial:
    • Volume: 42

Subject/Index Terms

Filing Info

  • Accession Number: 00127336
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Dec 16 1975 12:00AM