PREDICTING FLY ASH PERFORMANCE IN CONCRETE FROM PARTICLE CHARACTERISTICS By SHINHYU KANG Bachelor of Science in Materials Science and Engineering Kyonggi University Suwon, Republic of Korea 2010 Master of Science in Materials Science and Engineering Kyonggi University Suwon, Republic of Korea 2012 Submitted to the Faculty of the Graduate College of the Oklahoma State University in partial fulfillment of the requirements for the Degree of DOCTOR OF PHILOSOPHY May, 2020