By: John Hepfinger
A concrete paved drainage channel on the Interstate 74 (I-74) right of way in Moline, Ill., collapsed due to years of undermining from soil erosion and scour, which resulted in severe erosion of the entire downstream waterway area. The Illinois Department of Transportation (IDOT) wanted to repair and protect this channel from future erosion and was investigating possible repair solutions that would require minimal maintenance over time. Limited access to the channel, however, made conventional repair methods difficult.
IDOT’s District 2 design engineer learned about Concrete Cloth geosynthetic cementitious composite mat (GCCM) at the 2017 Highway Engineering Conference at the University of Illinois. He considered several repair options and determined Milliken infrastructure’s Concrete Cloth GCCM would be a practical, cost-effective solution for the project.
Solution
Concrete paving and riprap placement were considered, but each solution presented costly challenges that prevented consideration as a permanent solution. After reviewing Concrete Cloth GCCM’s application method and benefits, the design engineer chose it for the project.
The contracted team started the 30-day repair by using excavators and bulldozers to clear out woody vegetation and regrade the channel prior to the placement of stabilization systems. Steel sheet piling and weir walls were then placed to create a series of check dams in a stair step fashion to reduce the velocity of the water and to contain and mitigate future erosive runoff discharges. Finally, 22,400 sq ft of Concrete Cloth GCCM CC8 were installed in the drainage swale area between check dams beginning at the down slope outlet.
Results
Concrete Cloth GCCM allowed for the installation of a quick, permanent and cost-effective slope protection lining. The material will protect the channel from future aggressive erosion and suppress woody vegetative growth to reduce future maintenance on the limited access area. Approximately one year later, the repair location was re-evaluated, and the material was intact and functioning well.
