Skip to contentUnited States Department of Transportation - Federal Highway Administration FHWA Home
Federal Highway Administration Research and Technology: Coordinating, Developing, and Delivering Highway Transportation Innovations

Overview | Projects | Laboratory Capabilities

 

 

Aggregate and Petrographic Laboratory

 

Purpose: The Aggregate and Petrographic Laboratory (APL) at the Turner-Fairbank Highway Research Center provides facilities for the evaluation, preparation, and testing of aggregate sources, products, and samples for use in concrete, asphalt mixtures, and granular base course applications. Staffed by an experienced geologist and petrographer, the APL is able to assist in forensic evaluations of construction materials for others within Federal Highway Administration (FHWA) and with State departments of transportation (DOTs).

Laboratory Description: Facilities are available for characterizing highway materials using mechanical and durability tests, petrography and mineral identification, and through the Chemistry Laboratory with wet, analytical, and spectroscopic chemical methods. Included are an Analytical/Spectroscopy Laboratory, a Materials Characterization Laboratory, and modern x-ray diffraction and scanning electron microscopy tools and laboratories for conducting bench scale research. The Petrography Laboratory itself includes both petrographic and reflected light microscopes and image-capture tools, along with air-void parameter assessment using ASTM C 457 for hardened air-entrained concrete.

Laboratory Capabilities: The laboratory is capable of aggregate preparation and sizing, mechanical and durability testing, and working in conjunction with the Chemistry, Concrete, and Petrographic Laboratories. Additionally, aggregate physical, chemical, and mineralogical properties can be assessed in the Aggregate and Petrographic Laboratory.

Laboratory Equipment: Laboratory Equipment: Equipment includes a mineral grinder and pulverizer, screening, and washing equipment, and full sets of certified standard and intermediate-size sieves for coarse and fine aggregates and for the sizing of minus No. 200 micro-fine materials using sieves, hydrometer, and laser analysis. Various methods of shape, angularity, and texture analysis are available, including the AIMS II device as well as Superpave methods and petrographic analysis. Durability and compaction equipment include the Micro-Deval device for fine and coarse aggregate degradation in wet exposures and standard and modified proctor testing and permeability equipment. Cutting, lapping, and polishing equipment for preparation of thin-sections and lapped and polished sections for analysis are also included.

Laboratory Services: Testing, characterizing, and preparing aggregate materials for evaluation in concrete, asphalt, and granular base course mixtures as well as trouble-shooting and forensic investigation of performance in pavement and structures applications. Assistance can be provided to FHWA Divisions, Federal Lands engineers, and to State DOTs in evaluating special materials or materials performance.