Microwave apparatus and method for analysis of asphalt-aggregate compositions

Abstract

A method and apparatus are disclosed for analyzing the aggregate content of asphalt-aggregate compositions. The method includes placing a preheated, preweighed container carrying a sample of an asphalt-aggregate composition into a preheated furnace with the preheated furnace being warmer than the preheated sample, continuing to heat the furnace while drawing air through the furnace at a rate that avoids impeding the heating of the furnace or the sample until the sample in the container reaches its combustion temperature and the combustion of the sample becomes exothermic, initiating a second draw of air around rather than through the furnace to moderate the exterior temperature of the furnace, accelerating the draw through the furnace to increase the rate of combustion of the exothermic reaction, and reweighing the container and sample after combustion is complete. The apparatus includes a furnace, a housing around the furnace, a furnace exhaust in communication with the furnace, a housing exhaust in communication with the housing, means for drawing an airflow though the furnace and into the furnace exhaust, means for drawing a separate airflow though the housing and into the housing exhaust, and a junction between the exhausts that forms a common exhaust from the housing and the furnace.