Continuous concrete placement of bridge decks in multispan structures with additional retarder over supports

Title: Continuous concrete placement of bridge decks in multispan structures with additional retarder over supports
Author(s): F. Gallo, M. Rabkin
Paper category : conference
Book title: International RILEM Conference on Early Age Cracking in Cementitious Systems
Editor(s): K. Kovler and A. Bentur
Print-ISBN: 2-912143-29-2
e-ISBN: 2351580362
Publisher: RILEM Publications SARL
Publication year: 2003
Pages: 259 - 268
Total Pages: 10
Nb references: 5
Language: English

Abstract: Investigations of concrete decks in multispan bridges poured continuously even with retarder indicate that transverse cracks may be developed over the supports. Weak cross sectional properties of composite section over supports at early stages may be subjected to tensional forces caused by self weight of concrete placed at the same time in adjacent spans. Also change in curvatures and deflections may contribute to additional cracking of "green concrete". Stage placements reduce cracking, however the construction joints used in stage placement of decks are a source of water penetration and structural damage.

Revibration of retarded concrete for continuous bridge decks takes additional time and requires special screed design. Also the method is sensitive to the time of revibration. Abrasive resistance of riding concrete surface after revibration is most likely reduced.

Self-repair concrete with adhesives in chemically inert tubes, fibers or beads cast within concrete is very interesting solution but is not cost effective.

The authors proposed continuous placement of concrete with the use of additional retardation for concrete over the bridge supports. This method was successfully tested in stage I on approximately 75 Cubic M. of concrete placed for the New York City Department of Transportation in two spans of the Northern Boulevard Bridge over Cross Island Parkway, Queens, New York.

Online publication: 2010-06-02
Publication type : full_text
Public price (Euros): 0.00