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-SCD conforms to AASHTO MP13 Specification for Stainless Steel Clad Carbon Steel Plain Bar, which is based on ASTM A955 and ASTM A615.
- NX-SCD provides superior corrosion resistance relative to epoxy, galvanized and black bar and has been proven in long term field trials and tests since trials began around 10 years ago. NX-SCD have a superior critical chloride concentration threshold to induce corrosion of over 7kg/m3 in comparison to only 0.7-1.2 kg/m3 for epoxy coated rebar.
- NX-SCD requires zero maintenance because of the superior corrosion resistance and so there will be zero traffic disruption for the lifetime of the highway.
- NX-SCD does not generate galvanic corrosion when placed adjacent to black bar.
- NX-SCD has been fatigue tested to 2 million cycles (150MPa-275MPa) with no impairment to the metallurgical bond.
- Our unique manufacturing process provides a high bond shear strength between core and cladding of 300MPa when tested according to ASTM A263-88.
- An average stainless steel clad thickness of 0.8mm results in a durable outer cladding enabling NX-SCD to be easily welded (using 316 welding wire) into support cages or be handled using normal procedures for black bar, without impairment to cladding integrity.
- Extra-low adhesion of NX-SCD to concrete when coated with release agent.
- NX-SCD are currently available in 1-1/4” (32 mm) and 1-1/2” (38 mm) diameters, in standard lengths or they can be cut-to-length in a pickled finish.