The screed which is identified as the heart of the paving operation, smooths out irregularities in the mix with a floating action, while it's weight provides the first stage of compaction of the pavement. The screed's sensitivity and its finishing role requires that it receive the mix in an even flow. Factors which affect steady pull are identified, and the lift and approach angle of the screed which set the mat thickness are discussed. The material directly in front of the screed must be distributed by the augers along the full width of the unit. The automatic controls which help establish profile grade, transverse slope, and screed approach angle are outlined, and the factors important for good operation are noted. Improvements are noted which contribute toward easier operation of the paving machine (sophisticated controls), delivering a continuously consistent asphalt mix (by a hydrostatic and interlocked feeding system), achieving more tightly controlling grade and transverse levels (through inboard and outboard guides and crown-making screen adjustments), and attaining smoother roadability (through tire and track selection). Trends toward more economic use of asphalt (chip sealing, towed pavers, heater-scarifying treatment) are examined. Ripped out, crushed, treated and recycled material is described which appears to cut the cost of conventional hot mix by 25 percent, reduces bitumen consumption, and sharply curbs gas and fines emission.

  • Corporate Authors:

    McGraw-Hill, Incorporated

    330 West 42nd Street
    New York, NY  United States  10036
  • Publication Date: 1974-5

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00096900
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Sep 10 1975 12:00AM