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

影响混凝土结构的所有劣化机制都涉及气体或液体的输送过程。胶凝材料的输运特性和孔隙结构随龄期和暴露条件的变化而变化。这些变化的具体描述和量化是有必要的，以更全面地了解降解的机制，并预测混凝土的性能随时间的变化。吸附/解吸等温线是分析孔隙特征和输运性质的有力工具。与测量蒸汽等温线数据的其他方法相比，动态蒸汽吸收（DVS）平衡方法的三个关键优点是：快速（1- 5天的测试持续时间），精确（高精度平衡的连续测量），并且它可以防止胶结样品的碳化。使用DVS设备进行的实验是申请人研究计划的一个组成部分，以实现以下研究目标：量化和解耦水分粘合剂和离子粘合剂对输运特性的影响，以建立经验相关性；并区分化学水合作用和化学结合作用对材料微观结构和传输性能的影响。DVS实验结果将用于开发新的分析混凝土耐久性模型，以反映物理和化学过程。估计约有10名学生（3名博士，3名硕士）。（4名本科生），在获得DVS余额的前5年内将使用该设备并进行数据分析。预计该研究将通过改进对混凝土降解机制的理解和开发捕获物理和化学过程的分析耐久性模型，产生新的贡献并影响混凝土技术的进步。研究结果将通过期刊出版物、会议和讲习班广泛传播。

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.