摘要: |
Eleven Ontario rubber modified asphalt demonstration projects were evaluated in terms of pavement performance and environmental impacts, including recyclability. On the basis of generally poor short-term performance of eight dry process (rubber modified asphalt concrete) projects, it appears that this method of crumb rubber modifier use should not be pursued unless there is considerable care in materials selection, mix design, and mix production and placement. The wet process (asphalt rubber) shows promise because it appears that asphalt rubber can enhance the durability of these asphalt mixes. Use of crumb rubber modifier in cold in-place recycling was not a technical success. A project with recycling of rubber modified asphalt concrete indicates no technical problems with recyclability. The economics (life-cycle cost) of the dry process are not favorable. If the incorporation of asphalt rubber does decrease maintenance costs or extend service life, there is a potential for savings through the wet process. Available asphalt technology, whether conventional or rubber modified, is capable of meeting environmental regulatory criteria. It is recognized that some technical issues require resolution to optimize rubber modified asphalt technology, and further work must be undertaken in such areas as long-term performance. |