Influence of dispersion and location on pay adjustment in construction engineering

Acceptance procedures are usually defined in terms of the fraction of elements that fall outside certain specification limits, such as the data dispersion around a central tendency. In contrast, design methods usually consider measures of a central tendency or location (i.e., mean) or, occasionally, of a central tendency together with measures of data dispersion. Price adjustments can be derived from data analysis using empirical models or algorithms based on life cycle cost analysis. As a consequence, there is no common logical framework for designing, analyzing, testing, and accepting road and airport pavements. This study analyzes the dependence of pay adjustment on hot mix asphalt air void characteristics using several acceptance procedures. The results demonstrate that the transition from location-based to dispersion-based systems depends on the probability density function describing a given quality characteristic. The drawbacks of several methods, brought to light in the analysis and discussion presented here, informed a new model in which both location and dispersion indicators are considered. The model was applied to a case study, and practical applications are outlined.