Detection and Semiquantitative Determination of Phosphorous in Phosphorous Pentoxide Catalytically Blown Asphalt Cement--Lower Cost Canal Lining Program

摘要

The high resistance to field aging displayed by buried phosphorous pentoxide catalytically blown asphalt membrane canal lining indicated that a method for distinguishing this type material from other catalyst-prepared asphalt cements would be beneficial. Three laboratory methods developed for the isolation, detection, and semiquantitative determination of residual phosphorous in phosphorous pentoxide catalytically blown asphalt cement are discussed. Isolation of the phosphorous compound by ashing the sample is preferred to acid digestion because it is a faster and less tedious procedure. Two outstanding colorimetric procedures, molybdenum blue and phosphovanadomolybdate yellow, were investigated for the confirmatory test and the visual colorimetric semiquantitative test. The phosphovanadomolybdate method was chosen because it is much simpler, better adapted to field laboratories, and in the phosphorous concentrations described, the shades of yellow are as distinct as the comparable blue shades of the molybdenum blue procedure. (Author)