Kolluru V. Subramaniam
Associate Professor of Civil Engineering
Model-Based Microstructure Evaluation of Hydrating Cementitious Materials: Development of a Test System and Experimental Investigation
While Kolluru V. Subramaniam was a doctoral student specializing in structural engineering and mechanics at Northwestern University, and later a post doc at the NSF Center for Advanced Cement Based Materials, he became interested in helping economically disadvantaged students from Chicago’s inner city. He knew that City College had a mission of access to higher education, and he thought the Department of Civil Engineering might be a good fit. When he came to interview, he found an educational institution with a glorious past where dynamic young faculty members were serious about building an even brighter future. “The atmosphere was vibrant. Faculty from different disciplines were talking to each other, and I thought that it would be a good place for interdisciplinary collaborations,” he says.
The research which Dr. Subramanian is pursuing under his CAREER award will contribute to meeting the growing demands of civil infrastructure for high-performance concrete with assured strength and durability.
Cement, the backbone of concrete, is one of the oldest building materials known to man. It is also one of the most complex. “To develop stronger, more durable concrete,” says Dr. Subramaniam, “we need to learn more about what happens as cement goes from a slurry to a weight-bearing solid. The development of the internal structure of the cementitious material and the ensuing strength gain in concrete are the result of processes which take place during hydration, a chemical reaction between cement and water.”
Currently, non-invasive tools which allow for assessing the internal structure of hydrating cement are not available. Because the development of the internal structure at the nano and the micro-scale levels often has tremendous impact on final strength and durability, Dr. Subramaniam is developing an ultrasonic test procedure which will advance the state-of-the-art in monitoring microstructure development in cementitious systems. The information gathered through sound waves will be used to formulate a model-based representation of the cement microstructure using poroelastic theory. He will then explore the relationship between the internal variables of the microstructure and the properties of cement systems. And, finally, he will formulate microstructure-based predictive approaches to the development of specific properties.
Dr. Subramanian’s project entails collaborations with colleagues from the Chemistry Department, as well as from Electrical and Chemical Engineering. And, it involves minority students from high school through graduate school, specifically targeting minority women high school students in Harlem, with a view to enrolling them in City College’s engineering program.