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ASA Graduate Student Scholarship laboratory specimens) in the presence of different void logical (MR) fluid. By applying a magnetic field, the rheo- sizes and location along of the steel-concrete interface. logical properties of this fluid can be tailored to fit the 2. Better comprehend the factors influencing the position and specific needs of various applications in both oil/gas as well size of voids at the steel-concrete interface when using as civil engineering industries. A research project that I shotcrete, such as the reinforcing bar size being encapsu- have been involved with is the application of cement-based lated and the experience of nozzlemen. MR fluid in oil and gas well cementing to improve zonal 3. Integrate the steel­concrete behavior into a finite element isolation. A good cement job is the key to achieving suc- model (FEM) to gain better comprehension of the phenom- cessful zonal isolation. Insufficient zonal isolation could enon resulting from many other possible material proper- cause fluid migration, resulting in water aquifer contamina- ties and void and specimen geometry configuration. tion and loss of control of well pressure, shortening the life 4. Reliably assess and propose design criteria for design of wells and increasing the risk of blowout, which could codes with regard of the calculation of the development result in economical loss and environmental disasters. Our length for shotcrete structures. project has already shown many positive results using the cement-based MR fluid in well cementing, and a related Research Significance paper has been published in a recent Society of Petroleum This research intends to answer a pressing question by Engineers (SPE) conference. engineers that has been present over the years in technical My research on cement­based MR fluid can be extended papers7 and ACI meetings: How does one rigorously and to the shotcrete application. Compared to conventional accurately account for voids at the steel-concrete interface concrete, shotcrete shows superior hardened properties such to reliably account for them in standards and design criteria? as high strength, low permeability, and high durability, which This will increase the confidence level by which civil engi- interests me most. These advantages are extremely beneficial neers specify development lengths of reinforcement for to applications such as structure repair and restoration, shotcrete structures. It will also establish a guideline for them underground construction; and watertight structures such as to anticipate development length based on nozzlemen expe- pools, tanks, and domes. To improve the quality of shotcrete rience, thus resolving an important aspect of structural safety placement and to extend its areas of applications, a signifi- for civil and mining infrastructure. cant amount of research has been conducted that focuses on both the construction phase as well as the in-service perfor- mance of shotcrete. For example, during the shotcreting, the rebound level is a major concern affecting productivity, Qian Wu is a graduate student majoring in economy, and sustainability of shotcrete application. Also, civil engineering at the University of Texas just like other cement-based materials, shotcrete can crack at Austin, Austin, TX. She received her BS in after construction, threatening the bond strength, compres- civil engineering from both New York Uni- sive strength, and durability of such systems. My preliminary versity Polytechnic School of Engineering, study shows that there are a lot of potential benefits by New York, NY, and South China University applying cement­based MR fluid for shotcrete applications. of Technologies, Guangzhou, China, in a For the construction phase, cement­based MR fluid can 4-year dual degree program. Her research reduce the rebound level, increase the resistance to water interests include magnetorheological cementitious materials, washout, and reduce the fallouts due to vibration of the oil and gas well cementing, nondestructive testing of concrete, structures. For in-service structures, it is feasible to use structural health monitoring, and fiber-optic sensing. Wu is an cement­based MR fluid as a medium for nondestructive active member of ACI, ASA, ASCE, ASTM International, Chi testing based on magnetic methods and long-term monitoring Epsilon, and SPE. She also enjoys volunteering for UT Austin of structures. Engineering EXPO, EXPOLRE UT, and Austin Habitat for My other research area focuses on using fiber-optic Humanity. Wu will complete her master’s program in 2015 sensing technologies for structural health monitoring and will then continue to pursue her PhD degree in civil engi- and non-destructive testing, especially for crack detection neering with a focus on construction materials. and monitoring. Cracking in concrete defeats its inherent advantages of low permeability and high strength and also Research: Industrial Applications for influences its long-term durability. Thus, it’s important to have the ability to detect and evaluate cracks, continu- Cement-Based Magnetorheological Fluid ously monitor their growth, and explore their causes, which My research focuses on concrete and cement-based will significantly contribute to the repair of cracks in a materials, their industrial application, and their evaluation timely manner. and health monitoring. I believe my research will contribute to the concrete and One of my research areas focuses on the development cement industries to improve the productivity, economy, dura- of industrial applications for cement-based magnetorheo- bility, and sustainability of concrete and cement-based materials. 56 Shotcrete • Spring 2015


2015SpringShotcreteEMag
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