According to Tenax Corporation, there are three very important components for a good pavement design: drainage, drainage, and drainage. It’s well known that water in pavement systems is one of the principal causes of pavement failure. To prevent that, you need to quickly remove migrating fluids through a drainage system, such as the one being built above, engineered for the life of the structure.

Tenax’s Tendrain is a geocomposite drainage layer system that can be engineered to quickly remove subsurface water from the pavement, effectively separate structural fills from the native soil, reinforce the base course and restrain weak subgrade, provide a positive capillary break, and reduce damage caused by frost heave and subsequent thaw.

Tendrain’s engineered solution puts a compressive resistant, void-maintaining drain-age system into the pavement structure.

A performance evaluation by the Maine Department of Transportation determined that three test sections of pavement would incorporate a drainage geocomposite.

To qualify, it had to be highly resistant to crushing under dynamic and heavy loads, and had to be capable of rapid transmission of fluids (at least equivalent to 4 in. of free-draining base). Tendrain exceeded these criteria and was selected for use in the field tests.

Data from drainage monitoring outlets indicated the system provided excellent drainage based on AASHTO classifications.

It was found especially useful for removing the most damaging waters present during the spring thaw. An improvement in the structural number was proven using the falling-weight deflectometer test. The results indicated a 50 to 75% increase in the structural number compared to the original roadway sections. More information on the field performance test is available in a technical package from Tenax.

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When Sarasota County, Florida acquired a 24,565-acre, environmentally sensitive wetlands parcel to build a public use and education facility, the first phase of the project required constructing a 3,200-sq. ft. roadway to the building site and a parking area for 51 cars. The problem was how to efficiently and economially construct the access road and parking area over the wetland without disturbing natural subgrade materials.

Bids for alternative systems submitted by local contractors were cost prohibitive, but Presto Geosystems distributor R.H. Moore & Associates suggested that the Geoweb Cellular Confinement System be considered, and it was ultimately specified and used as the roadbuilding material. The company reports that the project was installed with county personnel and equipment resulting in a 45% savings.

The engineering firm required that the road and parking lot serve a dual function. The system had to support loads over poor soils and also be used as a stormwater retention system, storing the first inch of rainfall. The retention system consisted of 6-in.-depth Geoweb sections and #57 stone infill. Seven inches of #57 stone with 40% voids yields a capacity of 2.8 in. of water storage, a 2.8 safety factor. The permeability of the underlying soil is 3 in./hour which results in the system being available for the next storm within 2.3 hours, a safety factor of 31.3.

The roadway and parking area were built with the base approximately 8-in. below the natural surface to form a surface that was flush with the existing terrain. A geotextile was placed over the muck soil. Next, 6-in.-depth Geoweb sections were placed over the geotextile fabric and secured with stakes. The sections were stapled together and the cells infilled with #57 stone. Another 2 in. of stone was placed on top of the Geoweb system for maximum water retention and drainage.

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Cascade Distribution Ltd. says that EnviroBerm, shown above, right, is a state-of-the-art porous sediment control system that will reduce the velocity of flows within channels and ditches by up to 75%, and will dissipate the water’s energy up to 86% as it passes through a single structure. Key to the system are the M pins that hold the panels in place in any waterflow and sediment situation, and the pin driver that makes the installation quick and easy. A 12-ft.-wide ditch barrier can be installed from start to finish in under 20 minutes.

EnviroBerm has been approved for use by several DOTs, including New York, New Mexico, and Texas, and is being tested by many others across the country. During the past year, over 30,000 meters of panels were installed in Alberta, Canada, and they weathered some major storms with no blowouts or damage to the slopes involved.

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Sand bags have a wide range of applications in flood control, erosion control, fire control, and barricades. In most of these applications, speed is of the essence, so Hogan Manufacturing, Inc. has created machines to increase bag production and efficiency.

The ASB-3 Automatic Sandbagg’r has the capability of filling 1,800 bags/hour with wet or dry sand. It has a patented hands-free sand chute design for single or multiple operators and is completely self-contained with all-steel construction. One of the most important attributes is the rotator dispensing system that no other automatic unit has, the company says. The rotator is designed with three 120-degree offset metering cups. As the rotator assembly turns, the metering cups are filled and then independently dump the metered amount of sand down one chute at a time, automatically filling the bag. The design allows the pre-measured cup size to be adjusted for desired fill amounts and does not require the operator to hold the bag in place while being filled.

Hogan also has the smaller, manual Speed Sandbagg’r Model 300. It has a low, ergonomic design and can be used by one or more operators with a fill rate of about 225 bags/hour.

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