Rocky Mountain Rehabilitation

CDOT rehabilitates failing culverts with spray-applied geopolymer mortar

In January 2016, the Colorado Department of Transportation (CDOT) placed a project for public bid that included repair of several large-diameter highway culverts and a single box culvert. CDOT had specified a spray-applied culvert lining under a special revision to Section 603 of its standard specifications. To bid, contractors were required to be prequalified with significant lining experience, and all products were required to be listed on the CDOT approved products list.

Rehabilitation Solution

The project was awarded to Inland Pipe Rehab LLC, which had submitted qualification on over 50,000 linear ft of large-diameter pipe lining with Milliken’s GeoSpray geopolymer mortar. The project consisted of seven individual pipes spread across Jefferson, Douglas and Arapahoe counties. The full project consisted of:

  • 1,100 linear ft of 48-in. corrugated metal pipe (CMP);
  • 252 linear ft of 50-in. CMP;
  • 900 linear ft of 60-in. CMP; and
  • 124 linear ft of 6-ft-by-7-ft concrete box culvert.

GeoSpray was used to complete this culvert rehab.


Stamped engineering designs for the project specified a range of application thicknesses between 1 in. and 1.5 in., depending on pipe diameter, of GeoSpray material to provide either a fully structural design for the CMP culverts or a structural enhancement for the box culvert, which would return the pipes to as-new condition. The project took approximately six weeks to complete, and CDOT is currently bidding several additional lining projects with spray-applied liners.

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920 Miliken Rd.
Spartanburg, SC 29304
United States

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