Use of high pressure liquid chromatography to determine the effects of various additives and fillers on the characteristics of asphalt
By: by P. W. Jennings and Joan A.S. Pribanic and ... Kari R. Dawson ; prepared for the State of Montana Dept. of Highways
Contributors: Pribanic, Joan A. S.; Dawson, Kari R.; Montana. Department of Highways; Montana State University (Bozeman, Mont.). Dept. of Chemistry
Publisher: Montana Department of Highways
Published: 1982
Place of publication: [Helena, Mt.]
Language: eng
Number of pages: 97
Subjects: Asphalt; Additives; Testing; Asphalt cement; Liquid chromatography; Aggregates; Bituminous mixtures; Pavement performance
Description: This project dealt with the molecular composition of asphalts and with the changes in asphalt composition that have been found to result from the inclusion of aggregate, additives, fillers and extenders in bituminous paving mixtures under normal production conditions in Montana. The method used in this project was high pressure liquid chromatography in the gel permeation mode. Changes in the molecular size distribution (MSD) of an asphalt, under carefully controlled laboratory processing, were shown to depend not only upon the specific asphalt, but also upon the aggregate, the additive, the mixing temperature and the time held at that temperature. Consequently, the MSD of the asphalt in a finished pavement cannot be predicted from the MSD of the original asphalt cement alone. A test method was developed, however, to simulate the net effect of plant mix processing, thus yielding an accurate prediction of the final MSD. In a continuing sub-study on asphalt 'aging', the molecular size characteristics of asphalts in highway pavements were shown to undergo only very minor changes after approximately two years. Earlier predictions of pavement performance, based on molecular profiles of asphalts from core samples removed soon after construction, were actually borne out in two cases that were major paving projects. Several recycling agents were shown to consist mainly of very small molecular size materials. When mixed with salvaged bituminous material, they appeared to be inadequate to compensate for, or to otherwise change, excessive amounts of large molecular size (LMS) material often found in the salvaged asphalt. In another common method of recycling, it was found that the MSD of a mixture of asphalts can be estimated from the MSDs of the individual asphalts and their proportions in the mixture. As an example, a salvaged asphalt containing an excessive amount of LMS material may be modified with a virgin soft asphalt (i.e., 200-300 penetration grade asphalt with few LMS components) so that the resulting mixture closely matches the model for high quality asphalt cement.
Notes: "June 1982."

Performing organization: Dept. of Chemistry, Montana State University, Bozeman.

Final report; July 1980 - June 1982.

Sponsored by the Montana Department of Highways in cooperation with the U.S. Department of Transportation, Federal Highway Administration, MT/HPR/8090.
Table of contents: title: Disclaimer statement; title: Abstract; title: Introduction; title: Background; title: Summary of previous projects; title: Objectives; title: Review of data interpretation; title: Results and discussion; title: Refinement of methods; title: Extraction methods - ultrasonification; title: Extraction methods - comparison with MDOH method; title: Column selection; title: Effects of solvents used for mobile phase; title: Use of uv detector; title: Comparison of uv with RI detection; title: Isolation of LMS, MMS, and SMS fractions; title: Summary of section E; title: Precision; title: Use of the model asphalt; title: Laboratory simulation of field effects; title: Effects of heating, additives and fillers; title: Heat; title: Aggregates; title: Hydrated lime; title: Fly ash; title: Antistripping agents; title: Sulfur; title: Rubber; title: Carbon black; title: Summary of section IV; title: Aging of asphalts in pavements; title: Performance prediction/shadow specification; title: Recycling; title: Test sections; title: Conclusions.