Quality-Related Pay Adjustment Factors for Pavements

Hughes, Charles S; Moulthrop, J S; Tayabji, S D; Weed, Richard M; Jr, James L Burati

doi:10.17226/22656

Cited by 11 publications

(15 citation statements)

References 2 publications

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“…Effective QA programs can guarantee state highway agencies high standards of quality materials and construction practices ( 12 ). Typically, states use different asphalt mixture properties and specification values for acceptance testing.…”

Section: Application Of I-fit As a Quality Testmentioning

confidence: 99%

Understanding the Illinois Flexibility Index Test (I-FIT) using Indiana Asphalt Mixtures

Batioja-Alvarez

Lee

Haddock

2019

Transportation Research Record: Journal of the Transportation R

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Asphalt mixture cracking has become the dominant type of asphalt pavement distress in Indiana. In recent years, efforts have shifted away from the standard Superpave mixture design method in search of methods to improve the resistance of asphalt pavements to cracking-related distress. This paper presents a review of the applicability of the Illinois Flexibility Index Test (I-FIT) to evaluate the cracking potential of Indiana asphalt mixtures. In this study, two cracking indices were compared: the flexibility index (FI) and the cracking resistance index (CRI), both derived from the load-displacement curve. The applicability of quality assurance (QA) tests of laboratory-compacted and field-compacted samples was also explored to evaluate the cracking potential, and I-FIT was investigated for its applicability as a performance-related quality control (QC)/QA test. The results show that the FI values obtained from field-compacted samples were consistently higher than those of the lab-compacted samples. Both the FI and CRI values were significantly affected by variations in specimen thickness and air void content, with higher FI values observed with an increase in the air void content and a decrease in specimen thickness. The CRI values were less sensitive to I-FIT variability and more repeatable compared to the FI values. Finally, as an illustrative example, the cumulative distribution function of the FI values for a population of asphalt concrete (AC) mixtures was used to establish the different ranges for the quality thresholds of the materials.

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Section: Application Of I-fit As a Quality Testmentioning

confidence: 99%

Understanding the Illinois Flexibility Index Test (I-FIT) using Indiana Asphalt Mixtures

Batioja-Alvarez

Lee

Haddock

2019

Transportation Research Record: Journal of the Transportation R

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“…PRS are now often considered part of QC and relate directly to performance characteristics associated with a final product or service, and are the most widely used QA/QC specification for infrastructure projects that involve uniform construction methods and materials such as pavements and structural concrete for bridges. These PRS are linked directly to construction, materials and other items directly under the control of the contractor (Park et al, 2018;Buddhavarapu et al, 2014;Hughes et al, 2011;Mahboub and Hancher, 2001;Whiting et al, 1993). PRS largely hold the contractor responsible for the performance or quality of a finished product.…”

Section: Quality Management and Transportation Infrastructurementioning

confidence: 99%

Performance-related specification and payment modifiers in highway construction projects

Novak

Sullivan

Reed³

et al. 2018

IJQRM

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Purpose The ability to measure and assess “quality” is essential in building and maintaining a safe and effective transportation system. Attaining acceptable quality outcomes in transportation projects has been a reoccurring problem at both the federal and state levels, at least partially, as a result of poorly developed, inefficient or nonexistent quality assurance/quality control (QA/QC) processes. The purpose of this paper is to develop and implement a new QA/QC process that focuses on a novel double-bounded performance-related specification (PRS) and corresponding pay factor policy that includes both lower and upper quality acceptance and payment reward boundaries for bridge concrete. Design/methodology/approach The authors use historical data to design different payment scenarios illustrating likely industry responses to the new PRS, and select the single scenario that best balances risk between the agency and industry. The authors then convert that payment scenario to a pay factor schedule using a search heuristic and determine statistical compliance with the PRS using percent-within-limits (PWL). Findings The methodology offers an innovative approach for developing an initial set of pay factors when lifecycle cost data are lacking and the PRS are new or modified. An important finding is that, with a double-bounded PRS, it is not possible to represent pay factors using the simplified table PWL currently employed in practice because each PWL value occupies two separate positions in the payment structure – one above the design target and one below it. Therefore, a more detailed set of pay factors must be employed which explicitly specify the mean sample value and the design target. The approach is demonstrated in practice for the Agency of Transportation in state of Vermont. Research limitations/implications The authors demonstrate a novel approach for developing a double-bounded PRS and introduce a payment incentive/disincentive policy with the goal of improving total product quality. The new pay factor policy includes both a payment penalty below the contracted price for failing to meet a specified performance criterion as well as a payment premium above the contracted price that increases as the sample product specification approaches an “ideal” design value. The PRS includes both an upper and lower acceptance boundary for the finished product as opposed to only a lower tail acceptance boundary, which is the traditional approach. Practical implications The authors illustrate a research collaboration between academia and a state agency that highlights the role academic research can play in advancing quality management practices. The study involves the use of actual product performance data and is operational as opposed to conceptual in nature. Finally, the authors offer important practical insights and guidance by demonstrating how a new PRS and pay factor policy can be developed without the use of site-specific historical lifecycle cost (LCC) data that include detailed manufacturing, producing and placement cost data, as data related to product performance over time. This is an important contribution, as the development and implementation of pay factor policies typically involve the use of historical LCC data. However, in many cases, these data are not available or may be incomplete. Social implications With the new PRS and pay factor schedule, the Agency expects shrinkage and cracking on bridge decks to decrease along with overall maintenance and rehabilitation costs. A major focus the new PRS is to actively involve industry partners in quality improvement efforts. Originality/value The authors focus on a major modification to an existing QA/QC process that involves the development of a new PRS and an associated pay factor policy undertaken by the Vermont Agency of Transportation. The authors use empirical data to develop a novel double bounded PRS and payment schedule for concrete and offer unique operational/practical insight and guidance by demonstrating how a new PRS and pay factor policy can be developed without the use of site-specific historical LCC. Typically, PRS for in-place concrete have only a lower tail acceptance boundary.

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“…Thus, a quality measure that combines both the mean and standard deviation of air void into a single measure of quality serves better for QA. Recent studies have recommended using percent-within-limit (PWL) (or PD) in the QA over other quality measures (such as average absolute deviation, average, and range) (Burati, Weed, Hughes, & Hill, 2004;Hughes, Moulthrop, Tayabji, Weed, & Burati, 2011). The PD can be regarded as the percentage of the sample which is not qualified (outside specification limits, e.g., 2% and 8% air voids for HMA in the NJDOT specification).…”

Section: Derivation Of Model Equationmentioning

confidence: 99%

“…State-of-the-practice suggests that AQL value of PD equalling 10 is commonly specified by agencies. However, RQL value can vary from a high value of PD equalling 75 to a low value of PD equalling 40 (Burati et al, 2004;Hughes et al, 2011). The exponential performance model was checked at AQL and RQL and extreme values to see if it is reasonable (Table 1).…”

Section: Rational Check Of Modelmentioning

confidence: 99%

Derivation of pay adjustment for in-place air void of asphalt pavement from life-cycle cost analysis

Wang

Blight

et al. 2015

Road Materials and Pavement Design

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The objective of this study is to develop performance-related pay adjustment (PA) for in-place air void of asphalt pavements using pavement management data and life-cycle cost analysis (LCCA). In-place air void data were collected from quality assurance (QA) records for a large number of projects constructed in New Jersey from 1995 to 2005. Pavement condition index data were extracted from pavement management database for the pavement sections where air void data were available. Empirical pavement performance models were developed with sigmoidal functions and used to predict pavement service life. An exponential model form was used to relate the expected pavement service life to the quality measures of in-place air voids. After the rationality of the model was checked, LCCA was performed to derive the PA using different analysis periods and maintenance strategies. Monte Carlo simulations were conducted to capture the variation of PA due to the uncertainty of overlay service life. The PA could be significantly affected by the maintenance strategy if it is estimated using the short analysis period with single overlay, while the PA calculated using the infinite analysis period provides a conservative boundary that is not sensitive to the maintenance strategy. The developed LCCA framework provides the flexibility of determining the PA based on state agencies' practice on QA and pavement maintenance.

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Quality-Related Pay Adjustment Factors for Pavements

Cited by 11 publications

References 2 publications

Understanding the Illinois Flexibility Index Test (I-FIT) using Indiana Asphalt Mixtures

Understanding the Illinois Flexibility Index Test (I-FIT) using Indiana Asphalt Mixtures

Performance-related specification and payment modifiers in highway construction projects

Derivation of pay adjustment for in-place air void of asphalt pavement from life-cycle cost analysis

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