EXPERIENCE OF WEST VIRGINIA STATE ROAD COMMISSION IN DEVELOPING STATISTICAL SPECIFICATIONS

SOME RESULTS ARE DISCUSSED FROM A FOUR YEAR PROGRAM OF SAMPLING AND TESTING ON THE VARIATIONS OF THE CHARACTERISTICS OF MATERIALS. AGGREGATE TEST RESULTS SHOWED THE LEVEL OF QUALITY WAS SUCH THAT REQUIREMENTS FOR LOS ANGELES ABRASION AND SODIUM SULPHATE SOUNDNESS WERE BEING CONSISTENTLY MET. THE ACCURACY OF CURRENT METHODS OF DETERMINING ASPHALT CONTENT LEAVES MUCH TO BE DESIRED. A NEW RAPID METHOD OF TESTING PAVING MIXTURES FOR ASPHALT CONTENT IS BEING DEVELOPED. THE METHOD OF SIMULATION IS USED TO INVESTIGATE THE EFFECT OF USING NEWLY DERIVED STATISTICAL SPECIFICATIONS. A SERIES OF RANDOM SAMPLES, INDEPENDENT OF ROUTINE CONTROL SAMPLES, IS TAKEN OF MATERIALS FROM ACTUAL CONSTRUCTION PROJECTS. STATISTICAL ACCEPTANCE CRITERIA ARE APPLIED TO THE RESULTS OF TESTS ON THESE SAMPLES AND THE PERCENTAGE OF MATERIAL WITHIN LIMITS COMPUTED ALONG WITH ANY INDICATED INCENTIVE ADJUSTMENTS IN UNIT COST. ESSENTIAL STEPS IN THE DEVELOPMENT OF PRACTICAL AND REALISTIC STATISTICAL SPECIFICATIONS ARE: (1) SELECT PROJECTS THAT WILL USE MATERIALS FOR CONSTRUCTION ON WHICH VARIABILITY DATA IS AVAILABLE FROM PREVIOUS WORK (2) DECIDE WHAT TYPE OF ACCEPTANCE PLAN IS MOST SUITABLE, (3) ESTABLISH TENTATIVE CRITERIA FOR LOT SIZE, SAMPLING FREQUENCY, SAMPLING PLAN AND SAMPLING POINT FOR EACH MATERIAL OR ITEM OF CONSTRUCTION, (4) ARRANGE FOR INDEPENDENT RANDOM SAMPLES TO BE TAKEN AND POSITIVELY IDENTIFIED, AND (5) WHEN RESULTS OF SIMULATION SAMPLES BECOME AVAILABLE APPLY ACCEPTANCE CRITERIA TO DATA, COMPUTE PERCENT WITHIN THE TENTATIVE LIMITS, AND INCENTIVE ADJUSTMENTS, IF ANY. RESULTS OBTAINED FROM REPEATED APPLICATION OF THE SIMULATED METHOD WILL PREDICT THE PRACTICALITY OF ACCEPTANCE PLANS BASED ON PREVIOUSLY CALCULATED STATISTICAL PARAMETERS.

• Supplemental Notes:
  • pp 1-18, 1 FIG, 5 TAB, 4 REF, 1 APP
• Authors:
  • Steele, W G
• Conference:
  • Assoc Asphalt Paving Technol Proc
• Publication Date: 1968-2

Subject/Index Terms

• TRT Terms: Acceptance sampling; Acceptance tests; Aggregates; Asphalt content; Asphalt tests; Construction; Materials; Materials tests; Randomization; Simulation; Sodium sulfate test; Specifications; Statistical analysis; Statistical quality control
• Identifier Terms: Los Angeles Abrasion Test
• Uncontrolled Terms: Aggregate testing; Construction specifications
• Old TRIS Terms: Materials specifications
• Subject Areas: Construction; Data and Information Technology; Geotechnology; Highways; Materials;

Filing Info

• Accession Number: 00214811
• Record Type: Publication
• Files: TRIS
• Created Date: May 24 1994 12:00AM