Title:
Excellent After All These Years (Bridge Slab Subjected to 35 Years of Chloride Exposure)
Author(s):
Morris Schupack and David C. Stark
Publication:
Concrete International
Volume:
20
Issue:
5
Appears on pages(s):
29-35
Keywords:
bridge slabs; chlorides; corrosion; cracking; delamination; durability; permeability
DOI:
Date:
5/1/1998
Abstract:
A study was made of why a 35-year-old bridge slab subjected to deicing salts was in pristine condition. When demolished, the post-tensioned cast-in-place Connecticut bridge consisting of fourteen 120 ft (37 m) spans was found free of rebar corrosion and delaminations. Tests performed on salvaged slab specimens showed that chloride ingress was lower than it was for usual concretes. The slab behaved similar to a low water-cement ratio silica fume concrete. The excellent behavior is attributed to low water-cement ratio; high cement content; minimum cracking; well-graded fine aggregate; a high dosage of water reducer/retarder; good consolidation; good curing; good concrete cover-to-reinforcement; longitudinal compression in the slab applied 3 days after casting; and the stiffness of the superstructure.