POLYPROPYLENE MEMBRANE PROTECTS BRIDGE DECKS AGAINST MOISTURE, SALT DAMAGE

A non-woven polypropylene black waterproofing fabric applied between asphalt binder and asphalt overlay has been used to prevent deterioration of underlying bridge surfaces. The fabric is available in 75 and 150 inch widths and special order widths, and in rolls of 100 yards. In a Kansas City project, liquid asphalt cement (85 to 100 penetration) using 0.35 gallons per square yard was applied to the bridge deck at a temperature of 375 f. A No. 620 tractor-driven laying machine was used to install the special membrane stips 75 inches wide over the area coated with hot liquid asphaltic cement. A 2 inch asphaltic wearing surface was laid on the mat. The heat from the hot asphaltic wearing surface causes the asphaltic cement binder to saturate the membrane and tack the new overlay. The membrane absorbs approximately two-tenths of the asphaltic cement. This results in a homogeneous mass, binding the wearing surface and the mat to the bridge deck to form a strong barrier to resist moisture. A life of 10 to 20 years is expected for the water barrier. On previous bridge jobs, the membrane was spread and laid manually. A total of 555 resistance readings were taken on the deck: 98.7 percent were over 200,000 ohms; 98.4 percent were over 500,000 ohms; and 95.3 percent were infinite. The barrier system is effective in areas that previously showed reflective cracking and aligator cracking. The system has also helped correct correct deteriorating curb areas.

Media Info

  • Features: Photos;
  • Pagination: p. 32-33
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00128583
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Mar 10 1976 12:00AM