Events Calendar

Astani CEE Department Seminar

Speaker: Chiara Villani , Purdue University

Talk Title: Transport Processes in Partially Saturated Concrete: Testing and Influence of Liquid Properties

Abstract: The interest of the scientific community in transport properties of cementitious materials is motivated by their relevance in the service life prediction, an attractive instrument to move towards more sustainable construction practices. This aspect has encouraged the development of several transport tests. However, designing a transport test that is sensitive, robust, easy to perform, that provides a material property seems to be a real challenge in the case of concrete. Permeability tests have been proved to be highly sensitive to several parameters. In this context, this study aimed at investigating existing gas transport tests comparing their performance in terms of repeatability and variability. The influence of several parameters was investigated such as moisture content, mixture proportions and gas flow. A closer look to the influence of pressure revealed an anomalous trend of permeability with respect to pressure. An alternative calculation is proposed in an effort to move towards the determination of intrinsic material properties.

The impact of deicing salts exposure was also analyzed with respect to gas transport of cementitious materials focusing on their alteration of the drying processes. Limited information were previously available on liquid properties such as surface tension, viscosity, water activity in presence of deicing salts over a wide range of concentrations. To overcome this limitation, this study quantified those properties in a broad concentration range and at different temperatures. Existing models were applied to predict the change of fluid properties during drying. Desorption tests were performed to investigate the influence of deicing salts presence on the non-linear moisture diffusion coefficient. In an effort to predict moisture profiles semi-empirical models were applied to quantify the initiation and the rate of drying using liquid properties and pore structure information as inputs. Concrete exposed to deicing salts resulted to have a reduced gas transport due to the higher degree of saturation (DOS). This is believed to contribute to the premature deterioration observed in concrete pavements exposed to deicing salts.


Biography: Chiara Villani is a Ph.D. candidate at Purdue University. She received her B.S. and M.S. in Civil Engineering from the Polytechnic of Turin. Prior to Purdue University, she worked as a researcher in the CEMEX Research Group AG characterizing low carbon footprint fiber-reinforced self-compacting composites. While at Purdue, she investigated limitations and potentials of existing and new transport tests for permeability evaluations. She analyzed the deterioration mechanisms associated with deicing salts presence focusing on their influence on the drying process of cementitious materials. She has also contributed to the mechanical and microstructural characterization of sustainable composites containing supplementary cementitious materials and of composites cured with carbon dioxide. Her research interests include development and characterization of sustainable cementitious materials, drying processes in cementitious composites and durability of concrete structures.

Host: Astani CEE Department

Location: Kaprielian Hall (KAP) - 209

Audiences: Everyone Is Invited

Contact: Cassie Cremeans