Title: Large Girders Subjected to Alkali-Silica Reaction

Author(s): S. Multon, J.-F. Seignol, and F. Toutlemonde

Publication: Symposium Paper

Volume: 212

Issue:

Appears on pages(s): 299-318

Keywords: alkali-silica reaction; large-scale experiments; reinforced concrete; residual expansion; structural analysis; water content

DOI: 10.14359/12693

Date: 6/1/2003

Abstract:
An experimental study is being carried out at the Laboratoire Central des Ponts et Chaussees (LCPC), with Electricite de France (EDF) as a partner, to validate a methodology of mechanical reassessment of real structures damaged by Alkali-Silica Reaction (ASR) based on residual expansion tests on cores, and thus to answer to the needs of owners of civil engineering structures (bridges, dams, pavements). One major purpose of this study on structures is to point out the water driving effect on the swellings. The structures (3 m-long girders) were submitted to a unidirectional moisture gradient (bottom in water and upper face exposed to a 30% Relative Humidity environment), which causes a deformation gradient. Many tests on companion cylinders and prisms were carried out to determine the material expansion and mechanical characteristics. The paper focuses on numerous measurements obtained during the first year of drying: variation of water content, followed by precise weighing and gammadensitometry, relative humidity measurements; local and global deformations and deflection of the beams. Thus, the water effects on the behavior of structures damaged by ASR is documented and emphasized; and the methodology of computing structural deformations due to ASR using strains measured on prisms and cylinders can be validated.