LOAD TRANSMISSION CHARACTERISTICS OF ASPHALT-TREATED BASE COURSES

ASPHALT TREATED BASE COURSES WERE THE PRINCIPAL VARIABLE IN AN INVESTIGATION OF THE FEASIBILITY OF PREDICTING TRANSIENT DEFLECTIONS OF PAVEMENT STRUCTURES. THREE PROTOTYPE PAVEMENTS, 12 FEET SQUARE IN PLAN, WERE CONSTRUCTED WITH 8-INCH THICK BASE COURSES CONTAINING CLASS 2 AGGREGATE /STATE OF CALIFORNIA SPECIFICATIONS/ TREATED WITH THREE DIFFERENT ASPHALT MATERIALS' 85-100 PENETRATION ASPHALT CEMENT, SM-K ASPHALT EMULSION, AND MC-800 LIQUID ASPHALT. EACH BASE COURSE RESTED DIRECTLY ON A COMMON NATURAL SUBGRADE AND EACH WAS COVERED WITH A 3-INCH SURFACE COURSE OF ASPHALT CONCRETE. REPEATED LOAD PLATE TESTS WERE CONDUCTED AT THE SURFACE OF THE SUBGRADE, BASE, AND THE ASPHALT CONCRETE COURSE. RESILIENT DEFLECTIONS WERE MEASURED PERIODICALLY UP TO AT LEAST 10,000 REPETITIONS ON THE SUBGRADE AND TO AT LEAST 1,000 REPETITIONS AT THE TOP OF THE BASE AND SURFACE COURSES. IN THE LABORATORY, REPEATED LOAD TRIAXIAL COMPRESSION TESTS WERE PERFORMED ON REPRESENTATIVE LABORATORY PREPARED SPECIMENS OF THE MATERIAL IN EACH LAYER, INCLUDING INDISTURBED SUBGRADE SAMPLES, TO DETERMINE THEIR RESILIENT OR ELASTIC CHARACTERISTICS. IN ADDITION, FLEXURAL STIFFNESS MEASUREMENTS WERE OBTAINED FOR THE SURFACE COURSE AND THE ASPHALT-CEMENT-TREATED BASE MATERIALS. FOR EACH MATERIAL THE RESILIENT MOUDLUS WERE ESTABLISHED FOR A RANGE OF APPLIED STRESS, CONFINING PRESSURE IN THE TRIAXIAL TEST, AND TEMPERATURE FOR THE ASPHALT TREATED MATERIALS.FROM THE LABORATORY MEASUREMENTS, APPORPRIATE VALUES OF ELASTIC REPONSE WERE SELECTED AND USED TO PREDICT DEFLECTIONS IN THE PROTOTYPE PAVEMENTS. SURFACE DEFLECTIONS WERE CALCULATED USING TWO-AND-THREE-LAYER ELASTIC LAYER THEORY AS WELL AS BY ASSUMINING THE PAVEMENT SECTION TO BEHAVE AS A BOUSSINESQ MATERIAL AND WERE COMPARED TO THE DEFLECTIONS ACTUALLY MEASURED. THE RESULTS OF THIS INVESTIGATION WOULD APPEAR TO INDICATE THAT THIS APPROACH HAS POTENTIAL TO PREDICT PAVEMENT DEFLECTIONS UNDER MOVING WHEEL LOADS. IT MAY THUS BE USEFUL IN ASSESSING THE SO-CALLED LAYER EQUIVALENCY OF ASPHALT TREATED MATERIALS. HOWEVER, THE RESULTS EMPHASIZE THE FACT THAT NO ONE LAYER EQUIVALENCY CAN BE ASSIGNED TO A SPECIFIC MATERIAL BECAUSE OF SEVERAL VARIABLES, INCLUDING /1/ WHEEL LOAD AND CONTACT PRESSURE, /2/ STIFFNESS OR RESILIENCE OF THE PARTICULAR MATERIAL, /3/ LAYER THICKNESS, AND /4/ STIFFNESS OF THE OTHER MATERIALS. FURTHER, LIQUID- AND EMULSION-TREATED MATERIALS ARE INFLUENCED BY CURING CONDITIONS AND THE RESILIENT MODULUS MAY INCREASE WITH TIME. /AUTHOR/

• Supplemental Notes:
  • Preprint VoL, PP 730-766, 22 FIG, 15 TAB, 27 REF
• Authors:
  • Monismith, C L
  • Terrell, R L
  • CHAN, C K
• Conference:
  • Intl Conf Struct Design Asphalt Pvmts
• Publication Date: 1967-1

Subject/Index Terms

• TRT Terms: Accelerated tests; Asphalt concrete; Bituminous aggregates; Compression; Deflection; Elasticity (Mechanics); Measurement; Motion; Motor vehicles; Pavement layers; Pavements; Plate bearing test; Prototype tests; Repeated loads; Resilience (Materials); Stiffness; Surface course (Pavements); Temperature; Transient analyzers; Triaxial shear tests; Wheel loads
• Uncontrolled Terms: Moving vehicles; Pavement structure; Transient response; Triaxial compression
• Old TRIS Terms: Elastic theory; Layered system mechanics; Pavement deflection
• Subject Areas: Highways; Pavements;

Filing Info

• Accession Number: 00206656
• Record Type: Publication
• Files: TRIS
• Created Date: Aug 1 1994 12:00AM