...CAUSES OF DEFICIENT GROUT PT construction has been a significant part of the American infrastructure for more than 50 years. Bridges utilizing neat grouts had material deficiencies, notably in the form of grout voids and bleed water that led to corrosion of the steel strand. The Niles Channel...

.... ³³ The FHWA post-tensioning tendon installation and grouting manual (2013) ⁴ continues to refer to this test method. The test method was further developed by Schokker, 1999 ³⁴ , and Hamilton et al, 2000 ³⁵ and addressed complications with the electrochemical...

..., distribution of the current from the applied voltage perturbation and grout electrical properties is required. The testing in a general sense allow for detection of the natural corrosion rate. ²⁷ Since corrosion of strand in grout materials typically develops after depassivation by environmental...

... to conventional reinforcement, corrosion caused tendon failures have recently been reported, in some cases within but a few years of construction, as a consequence of either chemically or physically deficient grout (or a combination of the two), where the former involves elevated concentration of chlorides...

... to conventional reinforcement, corrosion caused tendon failures have recently been reported, in some cases within a few years of construction, as a consequence of either chemically or physically deficient grout (or a combination of the two), where the former involves elevated concentrations of chlorides or free...

... the critical passivation current. Sulfate ions have shown minor indication to increase the anodic current exchange density. Crevice and enhanced temperature did not seem to aggravate corrosion conditions. The pH of deficient grout extracted from corroded bridge tendons was typically ~13, but lower pore water...

... elsewhere, ¹⁴ an example of which is shown in Figure 2 . The analyses assume a wire/strand tension stress of 63 percent of GUTS or 1,172 MPa (170 ksi), and any time dependence for this was neglected. No correction was made such that the best fit line intersects the origin. Abstract Grouted...

...Abstract Analysis of deficient grout in Florida post-tensioned (PT) bridges where severe corrosion developed indicated enhanced sulfate ion concentration, high pore water pH, and enhanced moisture content. However, limited information is available on the corrosion behavior of PT strand in grout...

...Abstract After recent discovery of corrosion failure of tendons with deficient grout in a Florida bridge, other similar post-tensioned bridges in Florida have been inspected. Other bridges were found to have analogous deficient grout; however, the amount and level of severity of deficient grout...

...Table 1 Test Sample Matrix Base Grout Moisture Condition Repair Grout Neat Grout No Bleed Water Gypsum-Based Grout DI Water Augmented Bleed Water Simulated Bleed Water with Sulfate Repair Material 1,2,3 Field Extracted Tendon No Bleed Water Repair Material 1,2 Table 2...

...Abstract Recently, corrosion problems have occurred with new formulation grouts in post-tensioned tendons that were specified to meet low bleed-water requirements. Severe material deficiencies were observed in external post-tensioned tendons of several bridges in Florida, one of which had tendon...

...Abstract The assessment of recently failed external post-tensioned tendons from a bridge in Florida provided some insight on the material and environmental conditions of the tendon components leading to the failure. Segregated grout material was observed in the vicinity of the corrosion failure...

...Abstract The presence of voids in the grout of post-tensioned tendon ducts provides conditions whereby corrosion development may occur. The causes of the voids have been attributed to development of bleed water during grouting and subsequent re-absorption or evaporation from the grout. Poor...

..., as well EIS and LPR, to detect air space corrosion at the grout voids was also explored. The results showed that high sensitivity noise measurements (in the μV range) are feasible for the strand-anchorage systems. The potential and galvanic current trends for the assemblies suggest the presence...

...MODELING System Modeled The system simulated in this preliminary effort was a simple grouted cylinder with an axially placed 19-strand bundle (see Figure 5 ). The complicating geometry issue of strand distribution in the polyethylene duct as in Figure 5(c) was not taken into consideration...