Dynamic vapour sorption (DVS) balance to evaluate the microstructure of porous building materials

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All deterioration mechanisms that affect concrete structures involve either gaseous or liquid transport processes.  The transport properties and pore structure of cementitious materials change with age, and exposure conditions.  Specific descriptions and quantification of these changes is warranted to more completely understand the mechanism(s) of degradation and also to predict the performance of concrete over time.  Adsorption/desorption isotherms are a powerful tool to analyze the pore characteristics, and transport properties.  In comparison to alternative methods to measure vapour isotherm data, three key advantages of the Dynamic Vapour Sorption (DVS) balance approach are that it is: rapid (1- 5 days test duration), precise (continuous measurements with high precision balance), and it prevents carbonation of the cementitious samples.  Experiments conducting using the DVS equipment is an integral part of the applicant's research program to achieve the following research objectives: to quantify and decouple the moisture-binder and ion-binder effects on transport properties to establish empirical correlations; and to discriminate between the effects of chemical hydration and chemical binding on the material's microstructure and transport properties.  The DVS experimental outcomes will be used to develop  new analytical concrete durability models to reflect both physical and chemical processes.  It is estimated that approximately 10 students (3 Ph.D., 3 M.A.Sc., and 4 undergraduate), within the first 5 years of acquiring the DVS balance will use the equipment and conduct analysis of the data.  The research is anticipated to yield novel contributions and impact the advancement of concrete technology through an improved understanding of concrete degradation mechanisms and the development of analytical durability models, which capture physical and chemical processes. Research findings will be widely disseminated through journal publications, conferences and workshops.