NX Stainless Clad Dowels (NX-SCD) are made through a patented “green” process, which results in a metallurgical bond during hot rolling between a durable outer stainless steel cladding and a carbon steel core.
NX-SCD are designed with properties to optimize the very high corrosion resistance of stainless steel with the yield strength and elastic modulus characteristics of low alloy carbon steel, with the lowest life cycle cost in the industry.
Long-term pavement performance is a growing issue with many state departments of transportation. The FHWA study No. FHWA-RD-96-164 found that all epoxy coated dowel bars, exhibited various degrees of corrosion after only 5-10 years. In many cases, the corrosion was sufficient to cause joint lock-up and other pavement distresses.
"High Performance Rigid Paving was used in reconstruction of I-35 leading to the “Mall of America” in Minneapolis, one of the most highly trafficked freeways in the US. In excess of 120 tons of 38mm and 44mm diameter NX-SCD™ were used in this project so as to reach a “60 Year Pavement Life”, setting a new standard in pavement design and construction in the US and raising awareness of long-term performance of concrete pavements."
NX-SCD are an ideal material for longitudinal expansion joints in highway pavements, with their relatively thick stainless steel cladding of at least 0.8mm of stainless steel, compared with epoxy’s thin coating of less than 0.2mm. Wet Corrosion-Abrasion tests resulted in a Resistance Index of 3.62 for stainless steel versus carbon steel’s 1.0 (Material volume loss with increasing abrasion frequency).
NX stainless clad rebar (NX-SCR) is made through a patented process, which results in a metallurgical bond during hot rolling between a durable corrosion resistant outer stainless steel cladding and a carbon steel core.
NX-SCR combines the very high corrosion resistance of stainless steel with the yield strength and elastic modulus characteristics of low alloy carbon steel, while providing the lowest life cycle cost in the industry.
NX-SCR™ addresses structures’ corrosion problems where they occur, at the surface of the rebar. The typical amounts of corrosion from black steel rebar necessary to cause concrete cracking correspond to less than 0.1mm. In northern and coastal US bridge decks, such corrosion can occur within 3-5 years because of the use of de-icing salts.
"NX-SCR has been recently installed by the New York Thruway Authority Route 980D replacement bridge project on the bridge deck and in the superstructure. NX-SCR™ was selected by the New York Thruway Authority because it provides enhanced corrosion resistance and meets the FHWA guidelines for 75 year minimum design life criteria. NX-SCR™ was selected over solid stainless, epoxy coated rebar, and a number of other alternatives."
Life Cycle Cost Analysis studies have shown that standard concrete and NX-SCR provide the lowest life cycle cost while meeting the 100 year design requirement. In addition, a much higher tolerance to construction and concrete defects is possible using NX-SCR™in these environments.
NX-SCR has already been used for concrete reinforcement where de-icing salts are used on pavements and bridge decks. It is also the most economical and cost effective choice in marine environments and marine substructures. In these environments, even higher chloride levels accumulate over time than those caused by de-icing salts and are known to cause premature failures in existing rebar.