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Highway Materials Complex: Petrographic Laboratory

 

Purpose:  The Petrographic and Aggregate Laboratory is used to prepare and analyze aggregates, concretes and other highway materials using physical tests and microscopic (petrographic) methods.

Laboratory Description:  This laboratory consists of a "clean room" for conducting microscopy investigations and a sample preparation room for polishing and preparing samples for evaluation.
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Laboratory Capabilities:  All types of highway materials can be examined and characterized through the use of polished slabs and thin sections that are examined using different types of microscopes. ASTM forensic and petrographic methods for aggregate and concrete (especially air-void analysis such as ASTM C457) are used to evaluate concrete durability.

Laboratory Equipment: Equipment includes several types of microscopes (including an epi-fluorescent polarizing microscope), a semi-automated air void analysis system, image analysis hardware/software, slab lapping equipment, and thin-section preparation equipment. The AIMS II equipment for measuring aggregate shape, angularity, and texture is available for coarse and fine aggregate, and Micro-Deval (American Association of State and Highway Officials, ASTM) equipment is available for evaluation of the degradation of both coarse and fine aggregate under wet conditions. Other equipment such as saws, crushers, grinders, ovens, and chemical analysis equipment are available.

Services:  Services are available to aid other FHWA Offices, State Agencies and other highway materials researchers in evaluating materials and structures.

Read More:  Petrographic Methods of Examining Hardened Concrete: A Petrographic Manual, FHWA-HRT-04-150, July 2006