Grand Rapids Eight-Year Test - Grand Rapids, Michigan

ConShield Technologies, Inc.

Eight-year test concludes ConShield® treated concrete is superior to Calcium Aluminate cement in severe sulfide conditions. In 1999 the city of Grand Rapids, Michigan, under the direction of Chuck Schroeder, city engineer, embarked on a study to determine the optimal method for preventing concrete corrosion in sanitary manholes due to hydrogen sulfide gas. Turbulence, moderately high temperatures, and septic sewage create conditions that are ideal for sulfuric acid (H2SO4) production. Sulfuric acid is formed when aerobic (air-breathing) bacteria on the walls of the manholes metabolize hydrogen sulfide gas and oxygen. Their waste by-product is sulfuric acid, which results in the rapid decay of concrete. The technical name of this process is microbiologically induced corrosion (MIC).

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