Evaluation of Quality Control/Quality Assurance Implementation for Asphalt Concrete Specifications in California

Since 1992, the California Department of Transportation (Caltrans) has been working to improve quality in construction contracting and ultimately the quality of the product provided to the public. In 1996, Caltrans implemented quality control/quality assurance (QC/QA) specifications for asphalt concrete paving. These specifications require contractor QC and provide rewards or penalties based on statistical quality analysis of eight quality characteristics. These specifications were developed through a joint Caltrans/industry group and are supplemented with a QC manual. They were introduced through presentations to user/producer groups, appointment of district QC/QA coordinators, and training for engineers. In March 1996 the first project using QC/QA specifications for asphalt concrete went to bid and in the first year six projects were completed with them. Early projects were for the most part successful. Throughout 1996-1997, the specifications, the QC manual, and the implementation program were reviewed. Revisions to the specifications have been developed. The specifications and manual, issues, recommendations based on the 1996 projects, changes Caltrans has made for the continued use of QC/QA for asphalt concrete, and anticipated additional endeavors in the areas of QC/QA and materials testing are discussed here.

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Analysis of Contractor Pay Adjustment Schedule Using Simulation

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/0361198196154400113 ◽

1996 ◽

Vol 1544 (1) ◽

pp. 109-115

Author(s):

Robert P. Elliott ◽

Yanjun Qiu

Keyword(s):

Computer Simulation ◽

Quality Control ◽

Quality Assurance ◽

Quality Index ◽

Direct Analysis ◽

Detailed Examination ◽

Construction Contracts ◽

Simulation Process ◽

Control Quality

A common provision in quality control/quality assurance construction contracts is the adjustment of the contractor's pay on the basis of the quality of the construction. The expected impact of the provision on the pay should be examined to ensure that the adjustments are neither unduly severe nor excessively lenient. Most pay adjustment plans have been developed around a quality index by using a percent defective approach. Analyses of these plans are complex but reasonably well defined. Other plans, however, are more complex and do not lend themselves to direct analysis. These plans can be examined by computer simulation. The use of computer simulation to examine a complex pay adjustment provision is demonstrated. The analyses show that simulation can reveal that a pay adjustment schedule behaves differently than it appears on the surface. For example, the schedule examined bases pay solely on averages and appears to ignore construction variability. The analyses, however, demonstrate that the pay adjustments are at least as sensitive to construction variability as they are to construction averages. It is also shown that the simulation process can provide a better, more detailed examination of the pay schedule than is possible by simply determining the expected pay. In particular, the simulation process can provide an indication of the variability of pay at various quality levels and can identify the factors most responsible for pay adjustments.

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