Bridge designers might well use high performance concrete with internal
curing for
Short and Medium Span Bridges. Plagued with cracking problems, corrosion of
reinforcement, and lower service life, Short and Medium Span Bridges using
normal weight
aggregates and low water/cement (w/c) ratios can now have these problems resolved
through Internal Curing. The trend in high performance concrete to eliminate
drying shrinkage brought to light the adverse effects of autogenous shrinkage. This destructive type of shrinkage can be mediated through the substitution of a portion
of the natural sand with an absorbent structural grade lightweight sand, incorporated
saturated-surface-dry (SSD) into the mixture.
Short and Medium Span Bridges
Internal Curing benefits concrete bridge and parking decks subject to severe weather, attacks of de-icing salts, autogenous shrinkage and microcracks, and excessive permeability. It reduces permeability as well as autogenous shrinkage and provides greater strength both at early ages and at all ages.
Concrete pavements can accept traffic sooner with concrete using the IC Principle. The flexural strength with IC at 3 days is 75% of the normal weight 28 day strength value.
With HPC or with low w/c ratio (<=0.434) concrete IC is beneficial. As the w/c approaches 0.35 it becomes a must.
