POST-TENSIONING GROUT PROBLEMS Bonded post-tensioned structures are at increased risk of corrosion and failure of the tendons when there are defects in the installed grout. The most common grout problems (defects) include: • Voids: Voids are common at high points of tendon ducts as a result of grout bleeding and inadequate grouting. Standard cement/water grout has typically produced grout with 3 to 5% bleed. • Chloride contaminated grout: Chloride contamination may result from the use of chloride contaminated grout or mixing water or the long-term exposure of the structure to marine environments or de-icing salts. • Soft grout: Soft grout may be created if excessive water is added during grout mixing, and wick induced bleeding causes localized grout with high water-cement ratio. THE SOLUTION The Post-Tech PTI Impregnation system has been developed to mitigate corrosion caused by these problems. The system utilizes the interstitial spaces between the wires of each strand in a multi-strand tendon to deliver (transfer) a unique corrosion inhibiting, impregnation material along the length of the cable. The impregnation material seeps between the wires of the strands to impregnate the surrounding grout or concrete. The impregnation material is designed to form a corrosion-resistant film on any exposed steel surfaces such as steel strands which are exposed in grout voids, and to make the grout more corrosion and moisture resistant. Laboratory Confirmation Laboratory confirmation was completed on tendon specimens provided by one DOT and grouted “lollipop” samples. The tendon specimens provided to Vector were sections of external tendons which had been removed from an existing bridge. Lolipop samples comprised a single strand section which was centrally grouted in a cylindrical block of prepackaged PT grout. Laboratory testing confirmed the ability of the impregnation material to travel along the length of the specimen, to soak into the grout surroundingthe strands and to pass from strand to strand across the cross-section of a grouted tendon. Accelerated laboratory testing also confirmed the ability of the impregnation process to reduce corrosion by over 90%. Field Demonstration and case study The demonstration project was completed on external tendons in a box girder bridge in Jacksonville, FL (I-95 / I-295 Interchange). The demonstration project verified the capability of impregnating the full length of 256’ and 205’ grouted tendons from end anchorage locations, the capability of impregnating up to 100’ in each direction from a mid-point location, and the capability of the impregnation material to penetrate the grout adjacent to the strand. FDOT has implemented PTI Impregnation on the tendons of I-4 Connector in which soft grout was found. All selected tendons were successfully impregnated. Free water/moisture was pushed out of the tendons during the impregnating process. CONCLUSIONS Laboratory testing confirmed the ability of the impregnation material to travel along the length of the specimen, to soak into the grout surrounding a strand and to reduce corrosion by over 90% when exposed in an accelerated corrosion cell. Field demonstration at the I-95/295 Interchange in Jacksonville, Florida and Implementation on I-4 Connector in Tampa, Florida has demonstrated the following: • All strands of 256’ long grouted tendons can be impregnated full-length from an end anchorage location, • Impregnation material can flow up to 100’ in each direction from a mid-point location,. • Impregnation material can penetrate grout adjacent to a grouted strand, and • Free water/moisture can be pushed out of the tendons during the impregnation process.

Corrosion of reinforcing steel leading to structural deterioration and failure of reinforced concrete structures is a serious problem for port and highway agencies, and facility owners. Galvanic anodes have been used to extend the service lives of concrete structures since late 1990s. Embedded Zinc sacrificial anodes have been included in patch repairs of steel reinforced concrete structural elements suffering from corrosion since the mid-nineties. The anodes installed in a UK bridge in 1999 have been monitored, and 10-year data monitored data will be discussed. Galvanic anodes have been used widely in patch repair since then. Recognizing the inadequate monitoring of impressed current cathodic protection that will make it in-effective, distributed galvanic anodes were developed in early 2000s to address the global corrosion issues in concrete structures. Many departments of Transportation (DOTs) and Ministries of Transportation tried and monitored the anodes initially for a few years and considered the trials successes, and have widely used galvanic anodes in bridge decks, abutments, pile jackets and marine structures since then. This paper introduces different levels of corrosion protection offered by galvanic anodes and the various galvanic anode systems used in concrete structures. Various applications of the galvanic systems to extended service lives of concrete structures are presented.