Development of a Rapid Test Method for Asphalt Content Determination in Hot-Mix Paving Mixtures

摘要

A rapid test method was developed for the determination of asphalt cement content in hot-mix bituminous paving mixtures. It is based on the extraction of asphalt cement from mixtures with trichloroethylene and subsequent measurement of the transmittance of light through the extracted solution. A good correlation was found between the results obtained using the rapid test and those obtained using the standard test (ASTM D-2172, Method E1) for samples tested in the field at asphalt mix plants. The test uses a portable spectrophotometer and a metal can for extraction. The equipment needed for the test costs about $300.00 and is highly portable. The asphalt content can be determined in less than ten minutes. The possibility of using the rapid test on materials containing emulsified asphalt, slag aggregate, unusually high amounts of fine material (< No. 200 sieve) and recycled material was also studied. The test appears to be easily adaptable to emulsions and slag aggregate. It is unaffected by normal amounts of fine material, but may have to be modified for mixtures with high fines contents. More work is needed before it can be used on recycled mixes.