Concrete Mats

Revetment construction with concrete mats on the Mississippi River is unique. The process starts with the smoothing of the bank to a stable slope from the top to well beneath the water surface. Then the concrete mats are placed in the water along the base of the river. Before the development of the concrete mats the revetments were constructed using wood, typically hand woven willow planks.

Wood revetment construction
Revetment construction in the past was done with wood.
Smoothing the bank
Before placing the revetment, large floating draglines smooth the bank to a stable slope from the top to well beneath the water surface.
St.Francisville Casting Field
The St. Francisville Casting Field located 30 miles north of Baton Rouge. An average of 120,000 "squares" of concrete mattresses are cast here every year.
Concrete mat dimensions
Each "square" of concrete mat measures four feet in width by 25 feet in length by three inches thick. The individual mats are woven together with steel wire into flexible 140-foot-wide sections. Each square of woven mats contains almost one cubic yard of concrete.
Laying the mat
Once the assembly of the mattress is completed, the launching barge moves out into the the river along the mooring barge, allowing the mattress to slide over the edge. When the mattress covers the desired area, the cables are cut and the barges are moved to lay the next mattress.
Assembling the concrete mat
The concrete mats are assembled on the sloping deck of the launching barge into a mattress connected to launching cables which are anchored to the bank..