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Water Transport through Cracked Concrete Structures-Effect of Mixture Proportion on Separating Crack Geometry and
Lena Mengel1, Hans-Werner Krauss1, Dirk Lowke1
1Institute of Building Materials, Concrete Construction and Fire Safety, Technische Universität Braunschweig, Beethovenstraße 52, 38106 Braunschweig, Germany.
Materials (Basel, Switzerland)
|September 9, 2022
Summary
Concrete crack geometry significantly impacts fluid transport and structure durability. Aggregate properties, particularly size and shape, most strongly influence crack tortuosity and water flow rate.
Area of Science:
- Civil Engineering
- Materials Science
- Structural Engineering
Background:
- Separating cracks in reinforced concrete structures increase fluid transport, leading to durability issues.
- Concrete mixture proportions, alongside reinforcement and stress, influence crack geometry and fluid transport.
Purpose of the Study:
- To investigate how concrete mixture components affect crack geometry and water permeation.
- To quantify the relationship between aggregate characteristics and crack-induced fluid flow.
Main Methods:
- Investigated concrete mixtures with varying aggregate size, shape, gradation, cement type, and water-to-cement ratio.
- Utilized X-ray micro-computed tomography to determine inner-crack width variation and tortuosity.
- Performed permeation tests to measure water flow rate through cracked concrete specimens.
Main Results:
- Aggregate properties demonstrated the most significant influence on crack geometry and water flow rate.
- Increased aggregate size led to higher crack tortuosity and reduced water flow rate.
- Angular aggregates resulted in slightly higher flow rates compared to round aggregates for similar crack widths.
Conclusions:
- Aggregate characteristics are critical factors in controlling crack-induced fluid transport in concrete.
- Optimizing aggregate properties can mitigate durability problems associated with concrete cracking.
- Understanding crack geometry through advanced imaging is crucial for predicting concrete structure performance.
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