Deflection Testing & Analysis

A DYNAFLECT is a nondestructive testing device for measuring the strength of asphalt concrete (AC) pavements. Housed in a small trailer, the apparatus can measure the strength of pavement structures. Oscillating weights cause the pavement to deflect and rebound in a manner similar to a vehicle driving over a pavement surface. A weak pavement will typically deflect more than a strong pavement. Motion sensing geophones measure the amount of deflection caused by the oscillation of weights. The deflection data is then analyzed to determine whether failure has occurred or will occur in the future at a designated traffic volume.

Unlike most methods, DYNAFLECT deflection design is based upon the measured strength of the existing pavement structure. This process provides accurate results for all pavement structures regardless of condition. AEC combines this data with projected traffic loads and provides feasible design that is neither lacking nor over designed for the desired future life of the structure

Where many improvement projects compete for limited funds, deflection testing and analysis provides data that allows for a thorough evaluation of pavement conditions. Projects can then be prioritized based on sound empirical data rather than ambiguous modeling based on visual inspection, speculation, or gravel equivalencies.

Although common sense suggests the worst pavements should be repaired first, this is not always the best management strategy. Pavements with high levels of deflection but few failures can be rehabilitated for a fraction of the cost of future repairs resulting from neglect. Pavements with excessive deflections and numerous failures often require complete reconstruction.

By deferring projects requiring reconstruction, it allows project managers to attend to pavements that can justifiably be enhanced in the short term. Monies initially set aside for pavements that are determined to require reconstruction can often be shifted and applied to more time sensitive demands. In most cases, it is economically advantageous to defer a project requiring reconstruction as failure has already occurred and preventative actions will yield minimal benefits.