Use of Discarded Tires in Highway Construction

About the report:

In August 1978, bituminous surface treatments in which vulcanized rubber was blended with the asphalt cement were placed on two secondary roads by the Sahuaro Petroleum and Asphalt Company and the Whitehurst Paving Company. The work was jointly financed by the Federal Highway Administration and the Virginia Department of Highways and Transportation. The ground rubber from used tires was blended with AC-20 asphalt in amounts ranging from 20% to 22% by weight of the binder, and was applied at a rate of 0.60 to 0.69 gal./ yd.² The cover aggregate, No. 68 and No. 78 stone, was applied at a rate in excess of 40 lb./yd.² The adherence of the stone to the binder was excellent on a section of road that was relatively straight, had a good cross section, and received direct rays of the sun for most of the day. It did not adhere well on a section that had a lot of curves and a poor cross section and was in the shade a good deal of the day. The surface treatment did an excellent job of sealing cracks. In addition, it arrested and, in some cases, even remedied pavement distortions. Because the rubberized binder (1) does not flow as regular asphalt does, and (2) can be applied at a relatively high rate, and apparently is effective in sealing cracks, it is believed that it can be used to advantage for sealing pavements and bridge decks. The drawbacks in using the material are its high cost and the extended time required to blend the rubber and asphalt in the field. However, because of its performance over the two-year test period, the Department should consider: (1) further experimentation with the material on some badly cracked bituminous pavements, and (2) experimentation with the material as a bridge deck sealant.

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