U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
The Chemistry Laboratory conducts fundamental studies of highway materials to understand both failure mechanisms and superior performance. New standard test methods are developed to improve and facilitate the chemical analysis of highway materials and to characterize and quantify new or alternative sustainable materials.
Laboratory Description: Chemical characterization entails both sample preparation and analysis. Traditional wet chemistry techniques are used to modify paving and concrete materials and to prepare and condition samples for further testing and analysis. The chemical results are often tied to physical test results from the Binder, Bituminous Mixtures, or Concrete Laboratories, to complie a chemico-physico perspective and evaluate its effect on performance. The chemistry laboratory complex includes a laboratory for sample preparation and wet chemistry, and a laboratory dedicated to instrumentation.
This laboratory has all the necessary equipment for preparation of samples and standards for various analyses of liquid and solid samples. Specific equipment includes a nitrogen desiccator and glove box to prepare samples free of carbonation, a vacuum oven, muffle furnace, vibratory disc mill, centrifuge, ovens, an automatic fused bead preparation system, and a manual hydraulic pellet press.
Figure 1. Nitrogen glove box and desiccator to
prevent carbonation of different cementitious materials.
Figure 2. Example of platinum crucibles and prepared fused pellets of fly ash
specimens for elemental analysis using x-ray fluoresce spectroscopy.
This laboratory houses a wide variety of state-of-the-art analytical equipment for detailed investigations of highway materials ranging from the nano- to the macro-scale. This equipment includes:
Figure 3. Lapped and polished specimen of a grout-cement paste bond
used to study the microstructure in the interfacial region using the ESEM.
This type of specimen is used to understand how the distribution of porosity,
sand particles and specific mineral phases such as portlandite and
ettringite influence the mechanical performance of the bond.
Figure 4. Attenuated total reflectance FT-IR spectrometer
coupled with a state-of-the-art FT-IR microscope.
Figure 5. X-ray diffractometer performing quantitative powder diffraction
analysis of fly ash and other supplementary cementitious materials.
Figure 6. Synthetic sodium silica gel being analyzed using the Raman spectrometer
to understand the effect of alkalis in the silicate polymerization of the gel.
Figure 7. ICP spectrometer and auto sampler analyzing the ion concentrations of
concrete pore solutions expressed from different fly ash-cement binary mixes.
Figure 8. XRF spectrometer sample changer bed loaded with asphalt mix
samples used to detect the presence of waste engine oil residues.
Laboratory Services: The technology and data generated in this laboratory as well as the expertise of staff are being used by State transportation agencies to enhance the durability of highway materials and to reduce operating costs. The lab also assists Federal and State agencies in forensic investigations of premature highway failures.
The Chemistry Laboratory is currently performing research in four principal areas associated with pavement materials: concrete durability, sustainability, bond performance of grout/repair materials, and quality assurance of asphalt binders. The fundamental information gained from the research is key to developing new testing standards and field procedures to evaluate the adequacy of the original paving materials and also ensure the optimal mechanical performance and durability of the final mix design. In particular, research is being conducted in the following areas:
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Turner-Fairbank Highway Research Center
6300 Georgetown Pike
McLean, VA 22101-2296
|»||2011 FHWA Infrastructure Research and Technology Strategic Plan Goals and Objectives|
|»||Federal Highway Administration Office of Infrastructure|
|»||Pavement and Materials Discipline|
|»||Bridges and Structures Discipline|