CONSTRUCTION OF ASPHALT PAVEMENTS IN THICK LIFTS
ASPHALTIC CONCRETE PAVEMENT CONSTRUCTION IS DESCRIBED IN THE STATE OF WASHINGTON. AN INVESTIGATION WAS CONDUCTED ON THE EFFECT OF LIFT THICKNESS ON DENSITY AND PNEUMATIC COMPACTION METHODS. AN EXPERIMENTAL PROJECT WAS CONDUCTED TO INVESTIGATE THE EFFECT OF PLACING METHODS AND LIFT THICKNESS ON DENSITY AND RIDING QUALITIES OF ASPHALT CONCRETE. COMPACTION EQUIPMENT INCLUDED THREE TYPES OF STEEL WHEEL ROLLERS AND FOUR HIGH PRESSURE PNEUMATIC TIRED ROLLERS. COOLING CURVES WERE OBTAINED IN EACH SECTION BY INSERTING THERMOCOUPLES IN THE MIX AT VARIOUS LEVELS. SMOOTHNESS MEASUREMENTS WERE MADE BY A BPR ROUGHOMETER, A CALIFORNIA TYPE PROFILOGRAPH AND A WASHINGTON STATE ROUGHOMETER. ON THREE LEVELS OF LIFT THICKNESS, ROLLING PATTERNS WERE VARIED BY USING BOTH STEEL AND PNEUMATIC ROLLERS FOR BREAKDOWN COMPACTION, FOLLOWED IN ALL CASES BY STEEL FINISH ROLLING. TEST RESULTS SHOW THAT: (1) REGARDLESS OF LIFE THICKNESS PNEUMATIC BREAKDOWN PROVIDED THE HIGHEST DENSITY, (2) EQUAL OR HIGHER DENSITIES WERE OBTAINED WITH THE SINGLE LIFT, (3) THE RIDING QUALITIES OF THE FINISHED PAVEMENT WERE NOT AFFECTED BY THE DEPTH OR LIFT OR METHOD OF SPREADING THE BASE COURSE, AND (4) THE ROCK SPREADER PROVED TO BE A FULLY SATISFACTORY MACHINE FOR SPREADING THE BASE COURSE MIX. ANOTHER RESEARCH PROJECT WAS CONDUCTED TO ESTABLISH THE ROLLER WEIGHT, TIRE PRESSURE, AND NUMBER OF PASSES THAT WOULD INSURE UNIFORM OPTIMUM DENSITY AND PRODUCE AN ACCEPTABLE PAVEMENT SMOOTHNESS. AN ATTEMPT TO SHOW A DIRECT CORRELATION BETWEEN COMPACTIVE EFFORT, DENSITY AND PERMEABILITY WAS SUCCESSFUL ON THICK LIFT BASE COURSE. REASONABLE DENSITIES WERE OBTAINED OVER A WIDE RANGE OF COMPACTION VARIABLES, BUT THE MOST UNIFORM RESPONSE OCCURRED WITH THE 20 TON ROLLER. RESPONSE WAS MORE UNIFORM WITH INCREASED PASSES.
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Supplemental Notes:
- pp 206-215, 3 FIG, 2 TAB, 4 PHOT
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Authors:
- Minor, C E
- Publication Date: 1966
Media Info
Subject/Index Terms
- TRT Terms: Asphalt concrete; Asphalt pavements; Base course (Pavements); Compaction; Compactors; Density; Paving; Permeability; Riding qualities; Road meters; Thermocouples
- Uncontrolled Terms: Compaction equipment; Lift thickness
- Old TRIS Terms: Placing
- Subject Areas: Construction; Highways;
Filing Info
- Accession Number: 00215165
- Record Type: Publication
- Files: TRIS
- Created Date: Apr 28 1994 12:00AM