Dr. Priscilla Fonseca
Quinnipiac University
Will present a talk titled:
Quantification of voids and objects using digital image analysis
Abstract: Concrete petrography is a procedure used to determine the mineralogical, physical, and chemical characteristics of a sample. The most common reason to perform petrographic testing is to determine a cause of failure or reason for premature deterioration. However, there is a high barrier to entry in the field of petrography because expensive microscopes and other specialized equipment are used to examine the specimen. In this talk, I will show methods of quantifying the various phases in concrete using images of samples taken with a high-resolution flatbed scanner. Two approaches will be discussed: an automatic thresholding method using grayscale images of two-phase samples, and a color-based method that uses sample regions drawn by the user to segment into multiple phases. Both methods are implemented using a customizable Matlab script. This procedure reduces the need for specialized equipment and its associated proprietary software. While these methods were developed for the analysis of concrete, other materials can be analyzed as well. Recently, images of adhesives used in bonded joints have been studied with the same technique. For three-phase color images of concrete, the air voids, aggregates, and cement paste are segmented, while for both concrete and adhesive samples, the air void content and size distributions are quantified.
Date: September 17, 2021
Time: 11:00 am
SC 160
Bio: Priscilla Fonseca is an Associate Professor of Civil Engineering at Quinnipiac University. Her research is aimed at understanding the mechanisms and durability of porous materials, especially cement, concrete, and mortar. Her students are undergraduates-only and majoring in mechanical or civil engineering. Dr. Fonseca’s current projects include characterization of bubbles in frost-resistant concrete, the design of architectural, thin-walled concrete, and recently, the development of an open-source image analysis program for segmenting the various phases in concrete.
Dr. Fonseca teaches courses in mechanics, structural analysis, structural design, infrastructure engineering, and materials engineering. Her degrees include a Bachelor of Science in Civil Engineering at MIT, a Master of Science in Civil Engineering from University of Michigan, and a PhD in Civil Engineering from Northwestern University. Prior to graduate school, she was an engineer for two years in California performing seismic retrofits of the structural and piping components of nuclear power facilities. Dr. Fonseca holds a Professional Engineer license in the Commonwealth of Pennsylvania.
