Q: What are the performance characteristics of the SURTREAT corrosion inhibitors for steel reinforced concrete?
A: The environment surrounding imbedded steel reinforcement in Portland cement concrete is highly alkaline (pH 13). This supplies hydroxyl ions which serve to stabilize what is commonly referred to as the passivating film, a film of ferrous hydroxide/oxide (Fe (OH2). When chlorides are allowed to penetrate the concrete surface they attack the film and break it down. Once the chloride concentration is above a certain threshold the breakdown exceeds the stabilizing affects of the passivating film creating a corrosion active state. This will also occur if the pH is attacked through acid penetration. The Surtreat Total Performance System as detailed below is able to transform corrosion active concrete to a passive state as measured by corrosion current which can be converted to corrosion rate, an industry accepted standard. The Surtreat Total Performance System reverses the conditions that affect the durability of concrete by protecting against freeze/thaw damage, salt scaling, alkali aggregate reactions and sulfate attack.
SURTREAT TPS-II is a water soluble proprietary formulation containing a silicate ion component which penetrates and migrates through the cement micro gel pores and lining structure to the rebar level. It is an active inhibiting system providing corrosion inhibition through a reaction with the ferrous hydroxide/oxide film converting it into a more durable passive film which is significantly more resistant to chloride attack and breakdown and is no longer totally dependent on pH for its stability. Protection is provided both at the reinforcing steel and by a reduction of chloride ion ingress. The system inhibits rebar corrosion by causing a number of chemical and physical changes in the cement and on the rebar surface. TPS II reacts to reduce cement porosity, elevate pH and lower water soluble chloride content. TPS II is effective in preventing ferrous chloride complex formation by reacting with defective ferrous oxide ions prior to chloride attack and reforming the passive layer. It reacts at the rebar surface to convert rust into a strong chemically inert protective surface and to form a protective film on the steel rebar surface. It is the combination of all of these changes which give a long lasting, high level of corrosion protection.
SURTREAT TPS-XII is a water extended chemical formulation which migrates through the cement in the vapor phase to reach the rebar level where it forms a corrosion inhibiting film on the steel rebar surface to interfere with both anodic and cathodic reactions. It has proven to be most effective in inhibiting rebar corrosion which is primarily characterized by anodic hot spots. This is in contrast to cathodic only inhibitors that only reduce the average rate of corrosion.
Robert A. Walde, Chief Technical Officer, Surtreat Holding, LLC contact
Surtreat Holding, LLC 437 Grant Street, Pittsburgh, PA 15219; 412.281.1202, official website www.surtreat.info
Max Merzlikin, Surtreat Holding, LLC 2015