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Dowel bars are a critical structural component in jointed concrete pavements. As increasing emphasis is placed on the need for long-life pavements, it becomes extremely important to use construction materials that are capable of performing satisfactorily for service lives of 50 years or more.
Corrosion of steel reinforcement dowels in concrete highway joints is a major cause of premature pavement failures. This corrosion is caused by the intrusion of chlorides from deicing salts that migrate through the joints and porous concrete to the dowels. The steel corrosion products (rust) occupy 4-10 times the volume of steel consumed. This expansion creates internal pressure that impedes the essential movement of the dowel in the joint. The result is the premature failure of the pavement joint due to cracking and spalling of the surrounding concrete. This failure mechanism is one of the main contributors that significantly reduce the intended life of the pavement design.
Jarden Zinc’s LifeDowel™ utilizes proven zinc anode technology to protect the steel dowels from corrosion. The LifeDowel™ is produced by bonding solid zinc strip to the standard ASTM A615 steel dowel bar. In addition to the solid steel core, we now offer a structural steel tube core that has been tested and approved as a lower-cost option.
The LifeDowel™ provides two-fold protection. The thick layer of zinc acts as a surface barrier to chloride ion attack and is over 20 times the thickness found on a normal galvanized bar, thereby providing a higher resistance to surface breaches, scratches and wear abrasion than an epoxy-coated bar. Secondly, the zinc layer provides localized cathodic protection to any exposed steel due to incidental handling damage. The natural electropotential difference between steel and zinc creates a galvanic cell, whereby the steel bar is protected preferentially by the zinc.
The LifeDowel™ provides a long-term, cost-effective solution to long-life concrete highway pavement designs and is a key component to realizing true design life.