Geopolymer lining

Near Aurora, CO
GeoSpray®: CMP and Box Culvert Lining


In January of 2016, the Colorado Department of Transportation (CDOT) placed a project for public bid which 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 their 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 (IPR) as the low bidder. IPR had submitted qualification on over 50,000 linear ft of large diameter pipe lining with Milliken’s GeoSpray geopolymer mortar. The project consisted of 7 individual pipes spread across Jefferson, Douglas and Arapahoe counties.
The full project consisted of:
(a) 1100 linear ft of 48 inch CMP
(b) 252 linear ft of 50 inch CMP
(c) 900 linear ft of 60 inch CMP
(d) 124 linear ft of 6 ft x 7 ft concrete box culvert


Stamped engineering designs for the project specified a range of application thicknesses between 1 inch and 1.5 inches, 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 6 weeks to complete and CDOT is currently bidding several additional lining projects with spray applied liners.

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