The SFP1200 is perfect for thin overlays common in bridge deck rehabilitation work. It has a standard paving width of 12 ft. and can be extended to 14 ft. if required.
Many are excited about the Infrastructure Bill and what it means for expanding our nation's roads, bridges and highways. In addition to new projects, a point of emphasis needs to be on the current condition of America's roads and bridges.
The American Society of Civil Engineers (ASCE) gave America's bridges a Safety and Condition rating of C+. A major contributor to this poor rating is the age of our bridge structures. Bridges are built with an approximate lifespan of 50 years — the current average age of a bridge in the United States is 42.
Of the approximate 610,000 rural and urban bridges in the United States, more than 24 percent are considered functionally obsolete or structurally deficient. The stresses affecting the nation's bridges will only increase as traffic volumes rise and the demand for heavier semi-freight loads grows.
One solution is bridge deck rehabilitation, including and involving a bridge deck overlay system. Overlays have been in use for many years and can take many forms, but common use, best practices and high production are just now becoming mainstream.
While there are different manufacturers and different materials being used successfully, the different products have similar characteristics. They quickly develop a high tensile strength that seals, protects and extends the life of bridge decks by creating a highly durable, flexible and waterproof surface.
In addition to the protective seal, the bridge deck overlay:
- provides increased pavement grip in wet or dry conditions resulting in fewer accidents and more saved lives;
- is significantly lighter than the typical concrete overlay which requires a thicker application;
- reduces the bridge deck deterioration rate, which also reduces maintenance costs;
- is resistant to chemicals that cause corrosion — fuel, deicer and motor oil;
- reduces stopping distance, by increasing skid resistance and hydroplaning resistance — according to the FHW, 70 percent of wet pavement crashes can be affected by friction improvements;
- is fast curing — approximately one hour — less downtime/traffic disruption and the dollars associated with them;
- produces a strong bond yet has high elasticity, making it freeze-thaw resistant;
- is compatible with both steel and concrete decks; and
- certain products have no volatile chemicals odors — zero VOC.
Bridge deck overlays have traditionally been applied using batch mixers, forms and screeds. While adequate, many contractors who specialize in this type of work have moved towards volumetric mixer units to deliver the materials and self-propelled paving equipment for finishing.
HEM paving equipment manufactures two different models of overlay paver. Both models are modified slip form pavers with paving pan system designed for poly and other blends. These pavers are specifically designed for thin and ultra-thin bonded overlays — including UHPC, polymer and synthetic-reinforced.
Self-propelled, lightweight and easy to operate and maneuver, the HEM overlay pavers are ideal for bridge deck overlays, as well as mainline overlay and whitetopping projects. The SFP1200 is practical for thin overlays common in bridge deck rehabilitation work. It has a standard paving width of 12 ft. and can be extended to 14 ft. if required. It features a front spreader auger, stainless steel paving pans, pan-mounted vibrators, automatic front and rear steering and hydraulic sensors for grade and steering. A 67hp diesel engine delivers the power for the paver, which is standard with a rubber track drive, adjustable side forms, a lower work platform and operator's station.
The HEM SFP1800 overlay paver has all the features of the SFP1200, but it has a deeper, heavier frame, which allows it to span to wider paving widths — up to 20 ft. In addition, the 74-hp diesel engine also allows for other paving options, such as a tube roller paving package and a longer paving pan system, both of which are ideal for tear-out and replace panel and patch work.
For projects requiring an aggregate application to the paved material, HEM's AG1800 aggregate spreader is manufactured to match the SFP1200 overlay paver in paving width. The unit has a 67 hp diesel engine, a lower work platform and an operator's platform.
As a system the HEM overlay pavers and HEM AG1800 will reduce labor costs, provide a professionally paved surface and accurately dosed aggregates to conserve material, and avoid unnecessary cleanup, according to the company.
For more information, call 319/824-5551 or email [email protected].
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