Dehwah Osamah H A, Hamidane H'mida, Xi Yunping
Department of Civil, Environmental and Architectural Engineering, University of Colorado Boulder, Boulder, CO, 80309, USA.
Laboratory of Applied Civil Engineering, Echahid Cheikh Larbi Tebessi University, 12002, Tebessa, Algeria.
Sci Rep. 2024 Aug 8;14(1):18450. doi: 10.1038/s41598-024-66300-w.
Concrete durability is greatly influenced by the transport rate of aggressive chemicals. Moisture diffusion plays a key role in the long-term performance of cementitious materials, as it facilitates the entry of aggressive chemicals into concrete. The pore size distribution plays a critical role in determining moisture diffusivity. However, the characteristics of the concrete pore structure have not been included comprehensively in the material models so far. In this paper, a theoretical model was developed to obtain the pore size volume fractions for each diffusion mechanism including Molecular, Knudsen and Surface diffusions. An effective moisture diffusivity in concrete was then obtained using the weighted average based on the diffusion mechanisms and pore size volume fractions. The model's validity was demonstrated by comparing model predictions with available experimental data. The findings of this study provide valuable insights into the behavior of the concrete pore structure and its impact on moisture diffusivity.
混凝土耐久性受侵蚀性化学物质传输速率的影响很大。水分扩散在胶凝材料的长期性能中起着关键作用，因为它有助于侵蚀性化学物质进入混凝土。孔径分布在决定水分扩散率方面起着至关重要的作用。然而，到目前为止，混凝土孔隙结构的特性尚未全面纳入材料模型中。本文建立了一个理论模型，以获得包括分子扩散、克努森扩散和表面扩散在内的每种扩散机制的孔径体积分数。然后，根据扩散机制和孔径体积分数，采用加权平均法得到了混凝土中有效的水分扩散率。通过将模型预测结果与现有实验数据进行比较，验证了该模型的有效性。本研究结果为深入了解混凝土孔隙结构的行为及其对水分扩散率的影响提供了有价值的见解。
