Abstract: Composite construction of prestressed precast concrete and cast-in-place concrete having different concrete strengths are frequently adapted in the modular construction. However, current ACI318-11 design codes do not clearly define shear design methods for such composite beams. In this present study, simply supported prestressed composite beams without vertical shear reinforcement or only with horizontal shear reinforcement were tested to evaluate the effect of prestressed concrete on shear strength and shear design method for such composite members. The test variables were the area ratio of two concretes, prestress force, shear span-to-depth ratio, and shear reinforcement ratio. The results showed that shear strength was increased by increase of the prestress force and the prestressed concrete area, and decrease of shear span-to-depth ratio.

• Publication Date: 26-Oct-2014
• DOI: 10.15224/978-1-63248-030-9-29
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Abstract: In this paper, direct shear box test was employed for characterizing rheology of semi-solid, dough-like fresh cement-based materials tailored for extrusion. In total, five fresh cementitious mixtures, suitable for extrusion, were prepared and tested under various values of consolidation pressure and their shear yield strength was obtained. The results were interpreted by Mohr-Coulomb failure envelope. Effects of fiber volume, and water content on rheological properties of the fresh cement-based materials for extrusion were investigated. It was concluded that shear box test was an effective method for characterization of rheology of semi-solid fresh cementitious composites for extrusion. Water and fibers demonstrated different influence on overall rheology of the semi-solid, dough-like fresh cementitious composites for extrusion. The research findings will help for tailoring and optimization of material formulations of cement-based materials for extrusion.

• Publication Date: 26-Oct-2014
• DOI: 10.15224/978-1-63248-030-9-42
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• Downloads: 0