An European tour by U.S. highway engineers found that an asphalt mix used widely as an overlay or surface on high volume roads in Germany, the Netherlands and Scandinavia, called stone mastic or stone matirx asphalt (SMA) has the greatest promise for the U.S. Pioneered in Germany, SMA helps prevent rutting and deformation from heavy traffic. SMA is based on 3 factors: stone-on-stone aggregate contact that forms a 'structural skeleton,' increasing internal friction and shear resistance; hard stone used for aggregate; and high asphalt-cement content. The quality versus efficiency (SMA is 20-30% more expensive than comaparable dense-graded U.S. mixes) issue is discussed. A SMA evaluation program will duplcate the European experience on U.S. roads and then optimize the material selection and mix design. Demonstration sections placed in Michigan are described, as well as test sections in Missouri and elsewhere. The prospects for U.S. use are discussed and noted to be very favorable.

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  • Accession Number: 00621861
  • Record Type: Publication
  • Files: TRIS
  • Created Date: May 31 1992 12:00AM