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Investigating the Permeability and Mechanical Properties of Horizontal Joints in Roller Compacted Concrete Dams

Aziz Mohammadi, Morteza | 2019

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 53057 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Ghaemian, Mohsen; Toufigh, Vahab
  7. Abstract:
  8. Roller compacted concrete is a dry concrete with zero slump which is constructed in layers. Roller compacted concrete dams are generally weak in interlayers. The bonding strength and permeability of the interlayer affect the performance of the dam’s structure and its safety. In this study, the mechanical characteristics and the permeability of the interface layer of RCC are investigated by considering three key parameters, including water-to-cement ratio (w/c) of concrete, w/c ratio of bedding mortar and time interval between pouring each layer. More than 300 RCC specimens are prepared. To evaluate the properties of the interface between the mortar and the first layer surface, various tests were performed on the interlayer with different conditions. The bond strength of the interlayer is measured using the direct shear test and the direct tensile test. The permeability of the interlayer is evaluated by conducting the water permeability and the sorption tests. Results show that an increase in the time interval associated with a reduction of bond strength and high permeability of the joint. Furthermore, by increasing the cement content of the bedding mortar, the shear and tensile strength are improved, and the permeability coefficient is reduced considerably. Taguchi method was used to evaluate the effect of each variable means cement content of concrete, interval time and cement content of mortar on the results and the optimum mixing plan was achieved based on predetermined goals. The ANOVA was utilized to evaluate the level of influence of interaction variables. The relationship between the variables and responses was obtained using the Response Surface Method. Finally, the optimal mix design is achieved by Multi-objective optimization based on target strengths and water permeability
  9. Keywords:
  10. Roller Compacted Concrete ; Response Surface Method ; Direct Tension Test ; Direct Shear ; Response Surface Method ; Roller-Compacted Concrete Dam ; Water Permeability Test ; Layers Interface

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