A STUDY OF VARIABILITY IN AN ASPHALT CONCRETE MIX

BASIC STRUCTURAL PARAMETERS ASSOCIATED WITH THE SIGNIFICANT REQUIREMENTS AND CHARACTERISTICS SPECIFIED OR DESIGNED FOR HIGHWAY MATERIALS AND STRUCTURAL ELEMENTS WERE DETERMINED THROUGH STUDIES OF A BROAD SPECTRUM OF CURRENT GOOD HIGHWAY DESIGN AND CONSTRUCTION. DETERMINATIONS WERE MADE OF THE AVERAGES AND VARIATIONS IN TEMPERATURE, ASPHALT CONTENT AND AGGREGATE GRADATION IN AN ASPHALTIC CONCRETE WEARING COURSE MIXTURE PRODUCED BY ONE PLANT FOR A NORMAL JOB. AN EVALUATION WAS MADE OF THE EFFECTS OF INHERENT PROCESS VARIABILITY, SAMPLING PROCEDURE, AND TEST METHOD (MEASUREMENT PROCESS) ON THE VARIATIONS OBTAINED. RESULTS SHOWED THAT INHERENT PROCESS VARIABILITY WAS THE MAJOR FACTOR CONTRIBUTING TO VARIATION IN MIXTURE COMPOSITION AS DETERMINED BY EXTRACTION AND GRADATION TESTS. WHEN VARIABILITY IS EXPRESSED AS VARIANTS, APPROXIMATELY 60 PERCENT OF THE VARIATION IN ASPHALT CONTENT AND 85-98 PERCENT OF THE VARIATIONS IN GRADATION WERE ATTRIBUTABLE TO THE PLANT PROCESS. VARIATIONS ATTRIBUTABLE TO THE SAMPLING AND TEST PROCEDURES ACCOUNTED FOR THE REMAINDER OF VARIATION IN COMPOSITION. THE SAMPLING AND TESTING PROCEDURES USED IN THIS STUDY WERE MINOR FACTORS IN THE VARIATIONS OBSERVED IN MIX COMPOSITION, ACCOUNTING FOR SUBSTANTIALLY LESS THAN HALF OF THE VARIATIONS FOUND FOR EACH ITEM OF COMPOSITION. DEVIATIONS OF THE TEST AVERAGES FROM THE DESIGN VALUES WERE THE MAJOR CAUSE OF THE DEVIATION OF INDIVIDUAL TEST RESULTS FROM THE PERMISSIBLE LIMITS (TOLERANCES). THE FEASIBILITY OF CONDUCTING STUDIES OF THIS TYPE WAS INDICATED WITHOUT APPRECIABLE INTERFERENCE WITH THE NORMAL COURSE OF PLANT PRODUCTION. A STATISTICAL ANALYSIS WAS MADE TO SHOW THE EFFECT OF TEST METHOD, SAMPLING PROCEDURE AND MATERIAL (BATCH-TO-BATCH) VARIATION ON THE OVERALL VARIATIONS OBTAINED.

• Supplemental Notes:
  • Vol 34, pp 464-495, 4 FIG, 7 TAB, 8 REF, 1 APP
• Authors:
  • Oglio, E R
  • Zenewitz, J A
• Conference:
  • Assoc Asphalt Paving Technol Proc
• Publication Date: 1965-2

Subject/Index Terms

• TRT Terms: Aggregate gradation; Asphalt concrete; Asphalt content; Bituminous materials; Bituminous mixtures; Building materials; Chemical analysis; Mix design; Plant mix; Resource extraction; Sampling; Statistical analysis; Surface treating; Test procedures; Variables; Wearing course (Pavements)
• Uncontrolled Terms: Extraction (Chemistry)
• Old TRIS Terms: Bituminous surfacing; Gradation analysis
• Subject Areas: Data and Information Technology; Highways; Materials;

Filing Info

• Accession Number: 00210819
• Record Type: Publication
• Files: TRIS
• Created Date: May 24 1994 12:00AM