3 / 14
J u n e 0 6 - 0 7 , 2 0 1 9
P a r i s , F r a n c e
Page 35
Research & Reviews: Journal of Engineering and Technology
ISSN: 2319-9873
Civil engineering 2019
International Conference on
Structural and
Civil Engineering Research
T
his research investigated the use of locally produced ultra-high performance concrete (UHPC) as a grouting material to repair
deteriorated shear keys. Shear keys are used in adjacent girder superstructures to produce monolithic behavior and load
transfer across the structure. Shear key durability is a concern since shear key degradation can jeopardize the integrity of the
structure. Transportation agencies in the United States have reported that 75% of distress in adjacent girder bridges is due to
cracking and de-bonding along shear keys. Previous research has shown that locally produced UHPC has excellent mechanical
and durability properties. UHPC has also been shown to have good bonding characteristics that are desirable in a potential
grouting material. Several tests were conducted to evaluate the potential of UHPC as a shear key grout material. Bond strength
between UHPC grout and substrate concrete was evaluated using slant-shear and direct tension tests. Results showed that
adequate bond was achieved at seven days. Low strengths at 28 days were observed due to the low strength of the substrate
concrete. Shrinkage of UHPC grout was also investigated. Shrinkage at 28 days was less than 600 µ strain which is acceptable
for repair practices. Full-scale testing was used to evaluate load-deflection behavior of channel girder assemblages with grouted
shear keys. Results showed that UHPC grout and non-shrink grout had similar mechanical performance. Excellent bond was
achieved with all grouts, even with minimal surface preparation. In fact, the shear keys remained bonded to the girders even when
service load deflections were exceeded and no lateral restraint, such as post-tensioning, was provided. The similar performances
of the non-shrink grout and the UHPC grout indicates that UHPC grout does not provide a mechanical benefit over the non-shrink
grout.
newtson@nmsu.eduUltra-high performance concrete shear keys in
concrete bridge superstructure
Elsy Y Flores, Jordan Varbel, William K Toledo,
Craig M Newtson and Brad D Weldon
New Mexico State University, USA
JET 2019, Volume:8