EXECUTIVE SUMMARY

Concrete sawing operations are performed at pre-determined locations within the first 24 hours to prevent random cracking on jointed plain concrete pavements. In current construction procedures, the depth and the timing of the saw is usually established by the contractor based on experience. The objective of this study was to analyze the effect of several concrete mixture proportions and constituents on the early-age fracture properties and their effect on saw cut timing and depth for concrete pavements with several slab geometries. Concrete pavement mixtures with different coarse aggregate size and cementitious content were evaluated to determine the sensitivity of the measured fracture properties on saw cut model predictions. Finite element analysis was used to derive the geometric correction factors necessary to characterize the fracture properties of concrete based on the wedge plitting test configuration. A saw cut depth model proposed by Zollinger was modified to determine the timing and depth of notches on jointed plain concrete pavements. The theoretical analysis and practical example lead to the observation that if greater time is desired before saw cutting, the design should favor concrete materials with slower development of fracture properties. Larger coarse aggregate tends to increase concrete fracture toughness, and therefore will require deeper saw cuts. Thinner concrete pavements also require significantly deeper notch depth ratios relative to thicker slabs