Please see below for your interest a small selection of documents including independent studies conducted by US State and Federal Government Departments of Transportation supporting the use of Cladinox for +100 year infrastructure life. Click the titles for the full document...
AASHTO Specification promulgated by the Federal Highway (FHWA) and the US Departments of Transport (DOTs) in 2004 and then as a permanent specification in 2006, specifically to facilitate and encourage the wider usage of stainless clad rebar among US departments of transportation.
Dr Clemena summarising his conclusions after a 30+ year career spent investigating corrosion in concrete structures and their prevention. His final published research together with Dr Paul Virmani, Head of the Federal Highway Administration (FHWA) Infrastructure, in comparing several corrosion resistant steel reinforcing bars, as part of a FHWA sponsored landmark study by Virginia DOT which concluded with showing the equivalent corrosion resistance of stainless clad with solid stainless steel.
A presentation by Dr Clemena for a Japanese seminar showing the images of corroded “alloyed” steels after 245 days. After undergoing the same corrosion trials, Cladinox is continuing to show stainless steel’s permanent corrosion resistance even after 17 years.
This is an FHWA sponsored landmark study by VDOT showing the equivalent corrosion resistance of stainless steel clad with solid stainless steel. In contrast some alloyed steels corroded in less than a year.
A 2015 study showing Cladinox’s excellent metallurgical bonding and a great improvement over the earlier generation of stainless clad rebar by the same author.
In this report, Darwin advocated that only stainless steel and stainless clad bars reinforcing bar could be used as a stand alone corrosion resistance strategy whereas other reinforcing bars should be used in conjunction with supplemental corrosion strategies.
“Stainless steel clad reinforcement is recommended as a cost-effective direct replacement for epoxy-coated reinforcement. Cut ends of the bars should be protected with a system such as plastic caps filled with epoxy and the bars should be protected from damage to the cladding during bending operations.”
This FHWA report compared the relative corrosion resistance of stainless clad (labelled as “Stelax”, Cladinox Author’s earlier generation technology) showing that it is a permanent corrosion resistant strategy as opposed to merely delaying the onset of corrosion. Significantly, both Clemena/Virmani’s 2004 study and FHWA 2007 summary under the aegis of the FHWA publication shows stainless and stainless clad’s superiority.
“Slabs Reinforced With 316 Solid and Clad (SCR) Stainless Bars:
Thus, for the standard specimen simulated deck slab configuration the reinforcement types rank from best to worst, as:
316 ≈ Stainless Clad Reinforcing Bar >> 2201 > MMFX-II™ > 3Cr12 > Black Bar.”
This is the original paper by Kenneth Clear of concrete slabs fabricated for the test in 1982 containing stainless clad rebar, black, galvanised and epoxy. He showed that despite the stainless clad being an early version (later discontinued for economical reasons) it had the same permanent corrosion resistance as stainless steel.
Comparison by Kim Basham.
This Steel Dynamics Report shows the Kirkendall Effect of atom inter-diffusion across the interface between stainless and carbon.
The Ellingham Diagram is the basis of the complex chemical and metallurgical mechanisms interacting in Cladinox’s patented End Filter Technology.
12. R Tech Services Report showing Cladinox’s superior bond shear strength; well exceeding the standard’s minimum specification and well exceeding bond strengths achieved by conventional technologies.
The Bond Shear Strength tests as per 7.2 of ASTM 264-12 (7.2 of ASTM 264-12) carried out on a Cladinox billet during rolling, showed its bond shear strength after only 4 of the 18 rolling passes required to be rolled into a finished product, to be over 460MPa. This greatly exceeds the minimum requirement specified of 140 MPa and also exceeds strengths reported by industry majors.
In the Cui & Sagues report we find one of the main conclusions regarding the corrosion resistance of crimped-on PU pre-filled SS end caps as follows:
1. SCR with isolated ends or terminated with either a SS cap or welding overlay had high corrosion resistance in liquid solution with extremely high chloride levels (~5M Cl-). SCR with isolated ends or terminated with a SS cap remained passive in concrete with up to 8% Cl- by weight of cement for about 1 year."
Guide regarding concrete cover for carbon steel rebar and stainless, and therefore obviously applicable for stainless clad. Interestingly the previous generation of stainless clad rebar by Antonino Cacace (“Nuovinox”) is mentioned on page 45. Kindly note however, that the disadvantages cited are no longer valid; Cladinox can be made up to 50mm diameter and over 12m length. In addition end sealing by crimped on poly urethane pre filled stainless steel end caps which is routine, was proved to be as corrosion resistant as weld overlays - Cui and Saques 2003.
During our meetings with clients in the Middle East, the use of concrete additives has been brought up as an additional cost for use with certain steels. Cladinox will free you of these extra costs.
Further reinforced in this Guide with the “Progreso Pier” in Mexico: which despite the concrete being quite porous and of a much lower standard than today’s concretes, it is still standing because of the stainless steel reinforcing bar’s permanent corrosion resistance, even though the grade was 304 but made with earlier technologies and hence not as corrosion resistance as today’s stainless steels. Cladinox 316 has been routinely used; however even Cladinox 304L could be used with the same corrosion resistance and as a stand-alone corrosion strategy.
“A convincing documentation of the performance of stainless steel reinforcement in highly chloride contaminated concrete may be found at Progresso in Mexico. Here you find still operating, a 70 year old 2.2 km long concrete pier leading out into the Gulf of Mexico. This pier was at construction reinforced with stainless steel reinforcing bars (quality 1.4301). No corrosion has taken place within the structure, despite the harsh environment and poor quality materials used in the construction see Figure 1-5. The chloride levels, at the surface of the reinforcement were more than 20 times the traditionally assumed corrosion threshold level.”
This is Dr Clemena’s 2003 earlier study; this published paper on clad rebar for Virginia DOT compared bridge decks with epoxy and black carbon steel.