International Reports
| Report No. | AP2 (jot this number down to order) |
| Title | Modification of Paving Asphalts by Digestion with Scrap Rubber |
| Authors | Oliver, John W.H. |
| Publisher | Australian Road Research Board |
| Pub. Date | |
| Pages | 37 pages |
| Keywords | |
| Description | The service performance of sprayed surface treatments laid where traffic stressing is severe or where the existing pavement is cracked can be significantly improved if comminuted scrap rubber is digested in the asphaltic cement before spraying. Work has been dome to identify the factors, which are of importance in optimizing asphalt performance. Measurement of the deformation response of the digestions to sinusoidal loading indicated that the modified binder had improved response under the loading produced by traffic at high pavement temperatures and that produced by thermal contraction at low pavement temperatures. A simple and rapid test procedure was developed to measure the response under loading conditions approaching these. The procedure is to subject a prism of the binder at 60?C to a shear strain of 1.0 in creep and then determine the elastic recovery when the stress is removed. The most important factor affecting elastic recovery was found to by the morphology of the rubber particles as determined by the comminution process used in their manufacture. A simple bulk density test was used to characterize this morphology. Digestions of natural (truck tires) rubber are generally superior to those incorporating synthetic (car tire) rubber but are more affected by changes in the time or temperature of digestion. Where a cryogenic comminution process has been used only digestions of natural rubber particles produced a significant improvement in asphalt properties. Elastic recovery of strain in linearly related to rubber concentration. As rubber particle size decreases elastic recovery of the digestions increases. |
| Postage | $ 4.00 : U.S. $ 4.20 : Canada/Mexico $ 4.40 : Rest of the World |
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