Chemistry Laboratory

Overview

Purpose: To conduct fundamental studies of highway materials aimed at understanding both failure mechanisms and superior performance. New standard test methods are developed to facilitate the chemical analysis of highway materials and to characterize and quantify the additives used in them. Assistance is offered to State agencies in forensic investigations of premature pavement failures.

Laboratory Description: The two main functions of the laboratory are sample preparation and analysis. Traditional wet chemistry techniques are used to modify paving materials and to prepare and condition samples for further testing and analysis.

A wide range of modern electronic equipment is available for examining paving materials in great detail. These include:

• An environmental scanning electron microscope (ESEM) enables researchers to investigate morphological differences and chemical compositions of minerals, cementitious materials, metals, and coatings used in highway construction.
• An x-ray diffractometer (XRD) is used for the analysis of cement, concrete, fly ash, and aggregates and for studying the kinetics of cement hydration.
• An x-ray fluorescence spectrometer (XRF) is used to determine the elemental composition of cement, aggregates, and asphalt binders.
• An elemental analyzer is used to study how asphalt binders age by measuring their carbon, hydrogen, nitrogen, and oxygen content.
• A Raman microscope is used to study aggregates, nanomaterials, and alkali-silica reaction (ASR) gels.
• An inductively coupled plasma (ICP) spectrometer for the analysis of solutions.

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.