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new method of determining payment for in-place concrete with double-bounded compressive strength pay factors

Brief Project Description: Existing guidance for the use of a double-bounded pay factor system for the placement of concrete is inadequate if:

• The design distribution and/or the industry response is non-Normal

• The incentives and disincentives are not symmetrical around the peak of the design distribution With this project, we have developed a new approach for calculating performance from a lot distribution of 28-day concrete compressive strengths (CCSs) that is distribution-agnostic.

A new performance measure, the Percent Within Distribution (PWD), was discovered which replaces the PWL and addresses its shortcomings. The PWD can be used as a performance measure for this application regardless of the target distribution, the target mean, or the target standard deviation. It also provides better resolution for high-performing contractors. We have also created a MS Excel spreadsheet tool to facilitate the implementation of the new approach by DOTs. The decision-support tool will allow state DOTs and other agencies that fund transportation infrastructure to implement their own double-bounded pay factor system for 28-day CCS. The research team is currently working on the application of the new approach for 3 5-year forecast scenarios.


Fact Sheet     Video     Other     Q&A

Presenter: James Sullivan, UVM

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