Author(s):
R.N. Traxler
Publication Date
September 1962
Abstract
Objective: Determine how the durability of paving asphalts can be improved.|Experimental: Sixteen chemical additives from two different manufacturers were evaluated as antioxidants for 85-100 penetration paving asphalts. Thin films of the additive-containing asphalts were subjected to oxidation for various times at different temperatures and the viscosities of the hardened material determined in the microfilm (sliding plate) viscometer. The same type of data were obtained on the straight asphalt to determine the protection supplied by the additive.|Conclusions: The following conclusions are drawn from the data given in this report.|--(1) Chemical compounds are available which serve rather effecftively as anti-oxidants and free radical inhibitors when added to asphalt cements.|--(2) The retardation of hardening by these chemicals is most effective in asphalts that are highly susceptible to oxidation.|--(3) One to two weight percent of the additive material appears to be the optimum concentration.|--(4) The additives investigated are more effective against oxidation in the absence of light than against the severe hardening caused by photo-oxidation.|Recommendations: It is recommended that publicity be given to the results obtained to date in order to simulate development and promotion of even more effective additives by the chemical industry.|Future work: The manufacturer of the B series of additives is working toward the development of chemicals that will be even more effective then their additive B-8. When the new products are submitted they will be evaluated in asphalts of interest to the Texas Highway Department.|The Texas Transportation Institute has a contract with the National Bituminous Concrete Association which includes studies on additives that will improve the durability of paving asphalts. Work done under this contract will be coordinated to assure no duplication of the investigations under Research Project No. 15 and to guarantee maximum benefit to each sponsor.
Report Number:
9-3
Link(s):
Document/Product
http://tti.tamu.edu/documents/9-3.pdf
Publication/Product Request
TTI reports and products are available for download at no charge. If an electronic version is not available and no instructions on how to obtain it are given, contact the TTI Library.