A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Improved Grouts for Bonded Tendons in Post-Tensioned Bridge Structures
Currently, there is a serious problem in the United States and elsewhere with the deterioration of concrete bridges due to corrosion induced by chloride intrusion into the concrete. Historically the problem has been associated with conventionally reinforced concrete bridge structures as opposed to prestressed or post-tensioned structures. However, corrosion of steel tendons in prestressed concrete structures is of greater concern because the structural integrity of the bridge relies on the high tensile loading of the tendons. Any corrosion or corrosion-induced cracking of the tendon could lead to catastrophic failure of the structure. Grout is the final line of defense against corrosion of the steel tendon. Accordingly, FHWA initiated the study (1) to develop and test new mixture designs for grouts, (2) to develop and perform accelerated corrosion test methods on the new grouts, and (3) to compare the corrosion performance of the new grouts with the standard grouts. Several modifiers and additives for grouts were examined, including: high-range water-reducers, flyash, silica fume, latex polymer modifier, expansive agents, anti-bleed additives, and corrosion inhibitors. It was shown that these additives can greatly affect the fluidity, open-time, bleeding/segregation, chloride permeability, and mechanical properties of the grouts. Several experimental grouts were designed which provided improved properties compared to the more standard grouts presently being used. An accelerated corrosion test method (ACTM) was developed which evaluates the corrosion performance of steel tendons embedded in the grout. It was shown that any experimental grout that lowered the chloride permeability, increased the time for corrosion initiation and typically decreased the corrosion rate following initiation.
Improved Grouts for Bonded Tendons in Post-Tensioned Bridge Structures
Currently, there is a serious problem in the United States and elsewhere with the deterioration of concrete bridges due to corrosion induced by chloride intrusion into the concrete. Historically the problem has been associated with conventionally reinforced concrete bridge structures as opposed to prestressed or post-tensioned structures. However, corrosion of steel tendons in prestressed concrete structures is of greater concern because the structural integrity of the bridge relies on the high tensile loading of the tendons. Any corrosion or corrosion-induced cracking of the tendon could lead to catastrophic failure of the structure. Grout is the final line of defense against corrosion of the steel tendon. Accordingly, FHWA initiated the study (1) to develop and test new mixture designs for grouts, (2) to develop and perform accelerated corrosion test methods on the new grouts, and (3) to compare the corrosion performance of the new grouts with the standard grouts. Several modifiers and additives for grouts were examined, including: high-range water-reducers, flyash, silica fume, latex polymer modifier, expansive agents, anti-bleed additives, and corrosion inhibitors. It was shown that these additives can greatly affect the fluidity, open-time, bleeding/segregation, chloride permeability, and mechanical properties of the grouts. Several experimental grouts were designed which provided improved properties compared to the more standard grouts presently being used. An accelerated corrosion test method (ACTM) was developed which evaluates the corrosion performance of steel tendons embedded in the grout. It was shown that any experimental grout that lowered the chloride permeability, increased the time for corrosion initiation and typically decreased the corrosion rate following initiation.
Improved Grouts for Bonded Tendons in Post-Tensioned Bridge Structures
N. G. Thompson (author) / D. Lankard (author) / M. Sprinkel (author)
1992
150 pages
Report
No indication
English
Highway Engineering , Construction Equipment, Materials, & Supplies , Corrosion & Corrosion Inhibition , Grout , Concrete durability , Bridges(Structures) , Reinforcing steels , Corrosion tests , Admixtures , Specifications , Cost analysis , Test methods , Structural members , Concrete structures , Reinforced concrete , Post tensioning , Corrosion , Mechanical properties , Permeability , Corrosion prevention
Improved Grouts for Bonded Tendons in Posttensioned Bridge Structures
| British Library Online Contents | 1992
Advances in grouts for bonded post-tensioned concrete structures
| British Library Conference Proceedings | 1998
Sheaths for bonded tendons in post-tensioned concrete structures
| British Library Conference Proceedings | 1996