Limestone Filler in Asphalt Flux
Limestone filler is added to asphalt flux used for roofing shingles, primarily to reduce cost but has additional benefits of shingle durability and flame retardancy. The content of limestone filler in asphalt must be measured during and after the mixing process to ensure product consistency.
The most commonly used loss-on-ignition method involves measuring the weight loss of a bituminous mixture during combustion in a furnace. This test can take 40-60 minutes for ‘large’ samples, can be hazardous and costly, because of the temperatures used, and produces hazardous fumes that must be directed out of the facility.
The MQC benchtop Nuclear Magnetic Resonance (NMR) analyser offers a simple, rapid and environmentally friendly method for measurement of filler in asphalt which may be used for routine analysis in a production environment without specialist operator training.