Quality control of materials used during construction is an important issue routinely affecting highway agencies across the United States. Evaluating whether the materials delivered at the construction site agree with those specified can be resolved by existing testing techniques. Spectroscopy technologies have recently been used for typical transportation materials on a limited basis but there is the potential for much broader use of these technologies for quality assurance tests. Furthermore, recent advances in the development of portable equipment could allow evaluation of the materials at the construction site before or during their use. This report presents the evaluation of portable spectroscopy devices and their capabilities to “fingerprint” typical construction materials. Fingerprinting of typical materials requires developing acceptable spectra of the specific chemical compositions with laboratory-based equipment and then comparing the material being fingerprinted against those spectra. On the basis of this requirement, the project developed a library of reference spectra for common materials used in highway and road construction. The evaluation of the spectroscopy devices was conducted through laboratory testing and field testing. Field testing verified the feasibility of field quality assurance/quality control procedures for the material—testing method combinations found successful in the laboratory research phase. From this work the project also developed relatively simple and easy-to-use non-destructive testing procedures and protocols that inspectors could use in the field to ensure quality construction. An additional phase was recently added to this project to develop specifications and pilot them in collaboration with two transportation agencies. Once completed, the results from this additional scope of work will be published as an addendum to this report. (Author/publisher)
Samenvatting