In the past decade significant
advances have been made in the field of high performance concretes. The
next generation of concrete, Ultra-High Performance Concrete (UHPC),
exhibits exceptional strength and durability characteristics that make it well suited for use in highway bridge structures.
This material can exhibit compressive
strength of 28 ksi, tensile strength of 1.3 ksi, significant tensile
toughness, elastic modulus of 7600 ksi, and minimal long-term creep or
shrinkage. It can also resist freeze-thaw and scaling conditions with
virtually no damage and is nearly impermeable to chloride ions.
Prestressed highway bridge girders were cast from this material and
tested under flexure and shear loadings. The testing of these AASHTO
Type II girders containing no mild steel reinforcement indicated that
UHPC, with its internal passive fiber reinforcement, could effectively
be used in highway bridge girders. A large suite of material
characterization tests was also completed. Based on this research, a
basic structural design philosophy for bridge girder design is proposed.
Source: University of Maryland
Author: Graybeal, Benjamin Allen
Source: University of Maryland
Author: Graybeal, Benjamin Allen
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