Concrete interlayers

Q: We are interested in using a geotextile as an “unbonded concrete interlayer” over existing concrete pavement to float the new slab over deteriorated pavement, instead of a thin asphalt layer. Do you have any guidance for us in this regard?

A: Over the past several years, 16-ounce-per-square-yard (542-g/m²) nonwoven needlepunched geotextiles have been used successfully as concrete interlayers. The largest study was conducted on I-35 by the Minnesota Department of Transportation (however, Mo., S.D., Okla. and Ga. have also had success with this technology).

Geotextiles have very good benefit/cost as compared with hot-mix asphalt layers. In addition, the geotextile, in this application, has the following installation advantages:

No asphalt on project with multiple contractors or large equipment is needed.

Geotextile can be placed in challenging weather at a much faster rate than asphalt.

White geotextiles reflect solar radiation, which results in cooler surface temperature. This is good for workers
and the curing of concrete.

Check out the websites of Propex GeoSolutions, TenCate Geosynthetics Americas, AFITEX-Texel Inc., Maccaferri Inc. and Kaytech Industries Corp. for further details about geotextiles used in this application.