Bridges often need to be repaired at their joints, where two sections of concrete are connected. The Oklahoma Department of Transportation (ODOT) wants to know the feasibility of using ultra-high performance concrete (UHPC) to replace old bridge joints in Oklahoma. This is an effort to reduce costs and extend the time interval between bridge repairs. UHPC could make this possible due to its impressive tensile and compressive strengths, high durability, and low permeability when compared to Normal Strength Concrete (NSC). This project specifically analyses behavior of the UHPC/NSC interface during cyclical loading. I essentially "glued" (my words) two NSC slabs together with UHPC to make a model bridge connection. This was constructed with materials imitating what we can reasonably expect to find in an actual Oklahoma bridge with methods designed with field work in mind, for greater understanding of real world implementation. In the near future this project will see the model bridge connection cyclically loaded by a hydraulic press with loads just beneath and just above the expected cracking load.This project is ongoing at the time of writing, but results will include the cracking load and failure load of the model bridge connection as well as a better understanding of interface properties such as bond strength. I expect the UHPC repair to the model bridge joint will enhance the flexural strength of the entire structure and that the UHPC/NSC interface will have a bond strength greater than the NSC medium adjacent to it.
When I first started my research I only had experiences with chemistry laboratories from college classes. My research was done in Fears Engineering Lab on OU's research campus, and the tolerances of experimental design are much greater in this setting which initially surprised me. But when drilling holes in concrete or setting rebar on a hot day, small discrepancies are expected. This contrasted with, say, pipetting just the proper amount of liquid in a few experiments from my old gen chem labs.I also learned, unsurprisingly, that keeping a notebook to maintain a timeline and record observations and thoughts is a great way to stay organized and effective. Organization is key.
Broadest Impact, Curiosity to Creativity Summer Symposium 2018