Abstract
In the early life ofa concrete pavement, the pavement's tendency to change its volume due to temperature gradients and/or shrinkage can cause significant stresses due to pavement restraint to movement. Stress concentration on the tip of initial flaws or cracks leads to the propagation of these cracks. To avoid the formation of random cracks, it is common practice in jointed concrete pavement systems to induce cracks by sawcutting at specific joint locations. The spacing and location of the joints are typically determined prior to sawcutting operations. Current sawcut depth and timing requirements are related to the strength characteristics of the concrete pavement. A deficiency in this regard is that strength is not a material constant and it varies with structure geometry and size. It is common knowledge among practitioners and researchers that different test specimens provide different strength values. Also, it is unknown whether the strength obtained from the small specimens is representative of the actual notched pavement strength. New approaches that take into account the geometry and size effects are needed. An approach is presented to characterize concrete susceptibility to crack propagation. Such characterization which makes use of fracture parameters is used to determine sawcut depth and timing requirements for both longitudinal and transverse joints. The effect of slab thickness and aggregate types on those requirements is investigated and is useful in explaining the performance of different methods of sawcutting.
Published Version
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