Mengel Lena, Krauss Hans-Werner, Lowke Dirk
Institute of Building Materials, Concrete Construction and Fire Safety, Technische Universität Braunschweig, Beethovenstraße 52, 38106 Braunschweig, Germany.
Materials (Basel). 2022 Aug 23;15(17):5807. doi: 10.3390/ma15175807.
The increase in fluid transport due to separating cracks can lead to significant deterioration in the durability of reinforced concrete structures. Besides reinforcement and stress state, concrete mixture proportion has a significant effect on crack geometry. In this study, we investigated concrete mixtures with different aggregate size and shape, aggregate gradation, cement type and water-to-cement ratio with regard to crack geometry and resulting water permeation. Besides surface-crack width and length, we determined inner-crack width variation over depth and tortuosity by X-ray micro-computed tomography. Furthermore, we conducted permeation tests for each specimen. Among the mixture components tested, aggregates have the strongest effect on crack geometry and flow rate. Increasing aggregate size results in increasing tortuosity and decreasing flow rate. Furthermore, the replacement of round with angular aggregates results in slightly higher flow rates for a given crack width.
由于分离裂缝导致的流体传输增加会显著降低钢筋混凝土结构的耐久性。除了钢筋和应力状态外，混凝土配合比对裂缝几何形状有显著影响。在本研究中，我们研究了具有不同骨料尺寸和形状、骨料级配、水泥类型和水灰比的混凝土混合物的裂缝几何形状以及由此产生的水渗透情况。除了表面裂缝宽度和长度外，我们还通过X射线微计算机断层扫描确定了裂缝内部宽度随深度的变化以及曲折度。此外，我们对每个试件进行了渗透试验。在所测试的混合物成分中，骨料对裂缝几何形状和流速的影响最大。增大骨料尺寸会导致曲折度增加和流速降低。此外，在给定裂缝宽度下，用棱角状骨料替代圆形骨料会使流速略高。
