The Macroscopic Material Behavior Of Concrete

1645 Words Feb 1st, 2016 7 Pages
The macroscopic material behavior of concrete is influenced by the geometry, spatial distribution and material properties of individual material constituents and their mutual interactions. Therefore, it is essential to study the influence of each material constituent in order to estimate the residual strength of the structural components. Thus, failure of concrete is a complex phenomenon due to its multiscale and multiphase nature. When the normal stress in a material reaches its tensile strength, the inhomogeneities in concrete promote the formation of an inelastic zone ahead of an existing crack termed as the fracture process zone (FPZ). The FPZ is dominated by various complicated mechanisms such as crack shielding, crack deflection, aggregate bridging and microcracking around the crack tip and exhibits a post-peak softening behavior under tensile loading. It therefore becomes necessary to include these effects for predicting reasonably well the residual strength of existing cracked and damaged structures.
Bridging of coarse aggregate occurs when the crack advances beyond an aggregate that continues to transmit stress across the crack until it ruptures or is pulled out. The bridging aggregate may be considered to exert a closing pressure on the crack surface thereby resisting the crack growth and its magnitude strongly depends on the interfacial properties between coarse aggregate and cement mortar. Upon loading of plain concrete beams under three-point bending, it is…
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