Texas Tech University

Project 0-4681

Further Development of Binder Quality Assurance Program


The current TxDOT binder QC/QA system uses two asphalt binder supplier categories; suppliers who have an approved quality control plan (QCP) on file with TxDOT and those who do not. Suppliers who maintain a current QCP can obtain approval to supply binders either on a monthly- or a quantity-basis, while for others, each load of asphalt must be tested for specification compliance. Recently, a few binder supplier-grade combinations have experienced higher failure rates than in the past. Many TxDOT practitioners indicate an approved binder source does not always provide acceptable quality binders, and that a more robust QC/QA system is needed to ensure the supply of binders that both meet specifications and maintain a consistent level of quality. This research project was launched to develop a quality management system that utilizes the latest QC/QA principles by sharing the quality management burden between the supplier and the client (TxDOT). First, TechMRT researchers undertook a constructability review of binder quality for TxDOT operations. TxDOT districts, along with binder suppliers, and several contractors were interviewed to solicit their viewpoints on the existing binder quality management program, binder usage, quality problems and possible solutions. The Researchers also performed a comprehensive statistical analysis of binder test data. Three years of TxDOT test results (QA data) and several years of supplier (QC) data were analyzed using several statistical quality control methodologies. A sound binder supply quality management scheme requires the cooperation between binder suppliers and TxDOT. The burden of producing an asphalt binder that both meets specifications and
maintains a consistent level of quality lies primarily with the supplier. TxDOT has the responsibility to provide clear and specific guidelines for suppliers to follow, and to conduct random quality assurance tests. Based on this premise, the research product titled A Framework for TxDOT Binder Quality Management has been developed.

Project PI: Sanjaya P. Senadheera, Ph.D.

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