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.
- NX-SCR conforms to AASHTO MP13 Specification for Stainless Steel Clad Carbon Steel Plain Bar, which is based on ASTM A955 and ASTM A615.
- NX-SCR is available in Grades 300 and 400 (Grades 40 and 60) and meets the required bending diameters for ASTM A955 and ASTM A615.
- Superior corrosion resistance relative to epoxy, galvanized and black bar has been proven in long term field trials and tests over the last 20 years. NX-SCR has a superior critical chloride concentration threshold to induce corrosion of over 7kg/m3 in comparison to only 0.7-1.2kg/m3 for epoxy-coated rebar and is expected to have a 100-year service life.
- NX-SCR does not generate galvanic corrosion, when used adjacent to black bar.
- NX-SCR 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. The Kirkendall effect has been demonstrated and provides evidence of the sound metallurgical bond.
- An average stainless steel clad thickness of 0.8mm results in a durable outer cladding enabling NX-SCR to be handled using normal procedures for black bar, without impairment to cladding integrity.
- Ends can be sealed by application of plastic caps pre-filled with a suitable sealant.
- NX-SCR is available in standard lengths according to bar diameter and fully fabricated with ends sealed according to AASHTO MP13 in a pickled finish.
- Available diameter size range: #4 (13mm) - #10 (32mm).
- NX-SCR can be supplied in a standard length of 36 feet (11.6M) or they can be cut-to-length and fabricated in a pickled finish.
- Standard practices for handling stainless rebar should be employed when working with NX-SCR. Carbon steel bands, tie wires and lifts should not be used.