The repair includes the replacement of entire deteriorated strands, the replacement and coupling of portions of strands, and anchorage repairs. PT Repair and Replacement is the only option for PT cables that were identified as damaged during the post-tension evaluation process.
Post-Tech® Impregnation is designed to mitigate corrosion of grouted post-tension tendons, the process involves pushing an impregnation placed along the length of the tendon, leaving an anit-corrosion barrier film on the surface of the steel. Post-Tech PT Grease Injection is performed right after the Post-Tech Cable Drying process to prevent or minimize further corrosion deterioration. Post-Tech® PT Grease Injection is a proven cost-effective process where special rust-inhibiting grease is injected under pressure into the PT cable sheath filling cable voids, cracks, and porous grouts along the PT cable. The PT cables that require this treatment are selected by the Post-Tech PT Corrosion Evaluation process. Builders can partially tension tendons during the curing process to reduce this occurrence but it rare in production construction. The process is monitored and the treatment is ended only when dry condition of the cable is confirmed. Post-Tech® PT Cable Drying is a corrosion mitigation process where the moist air from the PT cable is replaced by dry non-corrosive air. Post-Tech® PT Corrosion Evaluation is a patented non-destructive test that identifies, and indirectly measures the extent of probable current or future corrosion deterioration in heat sealed or push-thorough cables exposed to a “wet” or potentially corrosive environment. Where previously, non-destructive tests and methods of corrosion protection were not available, Vector’s Post-Tech evaluation, drying, and grease injection systems of testing and protection can now be used. Corrosion can occur in grouted and ungrouted post-tension structures leaading to post-tension cable repair, in the presence of moisture and air in voids along the cable tendon.Įarly identification and mitigation of corrosive conditions can significantly reduce the costs of major repairs and the risk of structural failure. The cables are pulled to 33,000 pounds, resulting in 8 inches of elongation. Once the concrete has gained strength to 2000 psi, typically within the 3 to 10 days recommended by PTI, the tendons are stressed. Post-tensioned (PT) concrete deteriorates due to corrosion of post-tensioning strands. A post-tensioned concrete slab on grade will typically be 8 inches thick and use 3000 psi concrete. The stranded cables are slid inside of plastic. A post-tensioned foundation is a concrete slab foundation that is reinforced with stranded steel cables that are tensioned after the concrete hardens.
Post-Tensioned Corrosion Mitigation & Concrete Repair The first edition of the Post-Tensioning Manual was published in 1972, and as of the time of this writing (2018), they are up to their 6th edition.