Investigating the quality assurance of basecourse aggregates

Aggregate to be used in the basecourse layer of heavily trafficked flexible pavements with an Equivalent Standard load (ESA) greater than ten million, is required by the New Zealand Transport Authority (NZT A) to conform to the TNZ: Ml4 specification. This specification is an end-result specification, which is only concerned that the final material spread on the road surface. While an end-result specification has the advantage that the material used meets with the standards, it does not address the realistic issues of variation of a natural aggregate and performance. The variation in aggregate materials for road pavements is not well understood nor well implemented in the specifications. The issue of aggregate failing to pass M/4 is managed by inspection and personal judgment of the engineer. It is also common practice to blend materials to make up the deficient portion of the original failed material. This has not directly addressed the problem, which lies in the difficulty of meeting fixed standards set by the specification. Statistical specifications have been developed internationally, which in essence acknowledge the variations and the nature of the material, and address it appropriately through statistical models that consider the averages and standard deviation of sample material. This study reviews these statistical quality assurance techniques and investigates their appropriateness for the TNZ:M/4. Saunders and Hutchison (1990) developed a statistical quality assurance technique for M/4 aggregate in New Zealand. Unfortunately much of this work is unavailable and therefore the current research attempts to recreate their earlier work.

• Authors:
  • Al-Kubaisy, M
  • Widanapathirana, K
  • St George, J D
• Conference:
  • Seventh International Conference on Maintenance and Rehabilitation of Pavements and Technological Control
  • Location: Auckland , New Zealand
  • Date: 2012-8-28 to 2012-8-30
• Publication Date: 2012-8

Language

• English

Media Info

• Pagination: 9p
• Serial:
  • Issue Number: 00087

Subject/Index Terms

• TRT Terms: Aggregates; Base course (Pavements); Data analysis; Pavement design; Pavement performance; Quality assurance; Specifications
• Uncontrolled Terms: Materials technology (asphalt/bitumen/concrete)
• Geographic Terms: New Zealand
• ATRI Terms: Aggregate; Basecourse; Data analysis; Pavement design; Pavement performance; Quality assurance; Specifications
• Subject Areas: Highways; Pavements;

Filing Info

• Accession Number: 01455729
• Record Type: Publication
• Source Agency: ARRB
• Files: ATRI
• Created Date: Nov 30 2012 2:51PM