There must be an economic or design justification for an owner to consider
the use of the high-strength concrete for bridge girders.
Similarly, there must be an economic justification for an owner to select
HPC for a bridge deck. Usually, this justification is a longer service
life. High strength will usually not be a design advantage in a bridge
deck. Justification for use in bridge decks must be based upon improvements
in durability brought about by reduced chloride intrusion.
There are growing concerns over thermally-induced cracking resulting from
the very high cement contents used to produce high-strength bridge girders.
Combinations of portland cement, fly ash, and silica fume may allow
achieving the strength required while reducing the heat generated during
hydration.
There is also a concern about the higher modulus of elasticity and lower
creep of high-strength concrete in decks. Are these decks more prone to
shrinkage cracking than low-strength concrete?
The Silica Fume Association
38860 Sierra Lane, Lovettsville, VA 20180
Tel: 540.257.4224 Fax: 540.822.9456