Evaluate the Use of PWL As Payment Adjustment Factor for Asphalt Mixtures
-
2020-03-01
-
Details:
-
Creators:
-
Corporate Creators:
-
Corporate Contributors:
-
Subject/TRT Terms:
-
Publication/ Report Number:
-
Resource Type:
-
Geographical Coverage:
-
Edition:September 2017–July 2019
-
Corporate Publisher:
-
Abstract:The payment awarded to a Contractor for production and placement of asphalt mixes under Specification Items 341, 344, and 346 involves a payment adjustment factor that either awards a bonus or assigns a penalty to the base payment depending on the test results for laboratory-molded density (production) and in-place air voids (placement or construction). A characteristic feature of the current payment adjustment factors for production and placement is that these factors are based on average values of in-place air voids and absolute deviation from the target laboratory-molded density. In some cases, this practice results in a scenario where the Contractor delivers inconsistent quality but still receives a bonus because of the average performance. In order to overcome this weakness, several different quality measures including the Percent Within Limits (PWL) were reviewed as a part of this study. Data from TxDOT’s Site Manager database for 2004 and 2014 specification years were collected for all projects under the specification Items 341, 344, and 346. Data sets from 2014 specification years, covering approximately the last five years of construction across the entire state, were then used with hypothetical models for PWL and payment adjustment factor schemes to demonstrate: (i) the feasibility and financial impact of using the PWL based approach for bonuses and penalties, and (ii) the step-by-step process of using this approach for future implementation. An analysis tool was developed to evaluate the implications of adjusting various parameters in the PWL model using past data. This tool is intended to facilitate implementation of the PWL based approach. Implementation of PWL is certainly an improvement over the existing specification that is based only on average values. This approach also ensures that the quality of material produced or placed is consistent and rewards Contractors for meeting the specification limits consistently.
-
Format:
-
Funding:
-
Collection(s):
-
Main Document Checksum:
-
Download URL:
-
File Type: