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When a reinforced concrete member is put in tension, after cracking, the member elongates by widening of cracks and by formation of new cracks. Figure 1 Formation of internal cracks. Ignoring the small elastic strain in the concrete between the cracks, we can relate the crack width to the strain of the member by:
Concrete fracture analysis is part of fracture mechanics that studies crack propagation and related failure modes in concrete. [17] As it is widely used in construction, fracture analysis and modes of reinforcement are an important part of the study of concrete, and different concretes are characterized in part by their fracture properties. [ 18 ]
The crack arrestor can be as simple as a thickened region of metal, or may be constructed of a laminated or woven material that can be designed to withstand deformation without failure. When correctly applied, the technique is capable of redirecting movement and safely distributing stresses. [1] It is compatible with fail-safe design practices. [2]
Mode III is a tearing (antiplane shear) mode where the crack surfaces move relative to one another and parallel to the leading edge of the crack. Mode I is the most common load type encountered in engineering design. Different subscripts are used to designate the stress intensity factor for the three different modes.
The curing of concrete when it continues to harden after its initial setting and progressively develops its mechanical strength is a critical phase to avoid unwanted cracks in concrete. Depending on the temperature (summer or winter conditions) and thus on the cement hydration kinetics controlling the setting and hardening rate of concrete ...
The specimen is placed on the work table and a notch is created exactly at the centre. The crack should be generated such that the defect length is about half the depth. The load applied on the specimen is generally a three-point bending load. A type of strain gauge called a crack-mouth clip gage is used to measure the crack opening. [3]
A dowel bar retrofit (DBR) is a method of reinforcing cracks in highway pavement by inserting steel dowel bars in slots cut across the cracks. It is a technique which several U.S. states' departments of transportation have successfully used in repairs to address faulting in older jointed plain concrete pavements.
Typical crack pattern of the alkali-silica reaction (ASR). The gel exudations through the concrete cracks have a characteristic yellow color and a high pH. The fatty aspect of the exudations imbibing the concrete porosity along the cracks is also a distinctive feature of ASR. The alkali-silica reaction as a chemical cycle process