Repairs to Reinforced Concrete with Steel Corrosion
Distressed concretes with active corrosion and spalling of re-bar must be repaired prior to a failure. Examination of the concrete will yield chloride content, pH levels and strength data to assist in a prescription for repairs to insure longevity of a repair. StableCrete applied to an excavated area [ ready for patch materials ] will insure a superior bond of the patch material since the waterproofed surface will not allow absorption of patch material water, creating hairline shrinkage cracks at a patch interface. This waterproofing affect also maintains a low moisture- high ohms resistance concrete which suppresses anodic ring [ secondary spalling ] at a repair site. After placement of the repair/patching material is complete the entire new surface should be waterproofed to keep moisture and contaminates from entering the repaired area.
Sample of repairs to reinforced concrete with steel corrosion projects completed:
Project Launch Pad 39B Restoration, Kennedy Space Center, Florida
Owner N.A.S.A., United Space Alliance, Reynolds Smith & Hills, Inc.
Contractor Iveys Construction/H.I.S. Painting, Dave Heyne (321) 385-9155
Use Application to launch pad surface. Restoration, Kennedy Space Center, Florida. StableCrete chosen as the migrating, corrosion-inhibiting coating for concrete surfaces of crawler way, catacomb roof and Launch pad. These surfaces had been exposed to hydrochloric acid which is a by-product of propellant exhaust and water from the noise suppression system. Moisture had carried calcium a depth of four plus feet to the catacomb roof below and stalactites were being formed on the roof surfaces creating a hazard for workmen in the area.
Sherwin-Williams Hi-Mil Sher-Tar Epoxy applied to crawler way surface after StableCrete application.
Project Testing and Visual Inspection of Nine Year Old Tank
Owner Undisclosed at owners request
Contractor ConselcoR, Inc.
Use Visual inspection and basic petrographic test to exterior surfaces of a nine year old Wire Wound Pre-Stressed Tank at customers request. Two each 2MG clarifiers in service continuously since 2000. Obvious signs of corrosion bleed through/discoloration to all tank surfaces. Several spalls of wire corroding with rust stains at multiple locations. Samples indicated pH of 5, 3250 ppm Chlorides and unmeasured Sulphuric Acid content. Shotcrete material was not waterproofed at time of construction. Contractor relied on conventional coating for protection. Tanks located 20 feet from open digester with wind driven Hydrogen Sulfide being deposited on surfaces by prevailing winds. Immediate repairs recommended in order to arrest corrosion, restore pH levels and waterproof all exposed surfaces prior to new coating application. Re-Inspection schedule established to monitor repairs.
Project Phoenix Towers Condominium, Singer Island, Florida
Owner Old Port Cove Management, Dianne Fordering (561) 626-3100
Contractor A.T. Designs, Tim Marshall, P.E. (561) 881-7280
Use Applied to a poured concrete roof deck after concrete restoration was completed. Totally waterproofed a 25 year old deck area used as tennis courts above the parking garage below. Chlorides were detected throughout the entire structure and the decision to apply StableCrete to the top surface and repairs accomplished during this repair was made in order to slow the corrosion process that had already begun.
Waterproofing the top surface at this stage did stop further water intrusion however future repairs will be needed as the active corrosion cells continue to compromise the already salt laden concrete matrix. (Project was re-inspected five plus years later in November of 2006 with positive testing for a waterproof surface and minor surface spall repair needed. Thru repairs were under way and included bottom mat as well as vertical support columns which were then failing due to continued corrosion. (Owner advised at this time to consider installation of an impressed cathodic system in order to salvage the structure.)
Project Balcony Deck Replacement, Sunrise Condominiums, New Smyrna Beach, Florida
Owner Southeast Restoration, Inc., Bill Kiper (386) 304-4200
Contractor Concorr, Inc., Ali SohanghpurwalaBill Scannell (703) 729-7955
Use Use of Stable Crete as a curing agent/evaporation retarder on new poured 4000 psi concrete elevated decks. Far superior cure of new concrete, now totally waterproofed as well as preventing introduction of contaminates and loss of pH at reinforcing steel.