We recommend that slopes be 4 to 1 or flatter to eliminate the need to winch equipment. Thickness of each layer is monitored by the laydown equipment and can be carefully controlled by the operators. This tolerance is well within the safety margins required for performance in both permeability and structural integrity. The expected hydraulic conductivity is measured indirectly during construction by measuring the density and void content, a normal quality control test for asphalt paving mixtures. Final independent confirmation can be made using core samples tested in the laboratory, if needed.
Material uniformity is typically quite good throughout the mixture both laterally and vertically.
Joints between passes of the equipment are maintained hot by limiting the distance paved before backing up and placing the adjacent pass, or lane. Further assurance can be provided by joint heaters, specially designed equipment to maintain heat in the area of joints until final compaction can be achieved. Experience has shown that careful preparation and attention can result in joints readily meeting the required density and impermeability expected throughout the liner. Liner strength is such that it does not need a protective cover to protect from puncture and can withstand heavy equipment loading. The advantage of the ability to operate heavy equipment on this surface is that if a cell needs to be cleaned out for any reason, it can be accomplished without risk to the integrity of the liner.