Construction Quality Control of Unbound Base Course using Light Weight Deflectometer where Reclaimed Asphalt Pavement Aggregate is Used as an Example

Abstract

Reclaimed asphalt pavement (RAP) is already being recycled as a construction and building material. One of the commonly considered applications is to create an unbound aggregate from this material. However, since the particles of RAP have binder coatings, traditional quality control procedures applied during construction such as use of a nuclear density gauge does not provide accurate results. Therefore there is a need to find another method that can be applied during construction to confirm that the placement in the field meets the design criteria. For this reason, in this study, the suitability of using light weight deflectometer (LWD) has been investigated. The presented methodology outlines how to implement the use of LWD to create a target modulus in the laboratory as part of design criteria and compare with the field measurements. In the field, depending on the thickness of the constructed aggregate layer, the LWD measurements may be influenced by more than just the layer of interest. The presented methodology also provides a solution for such multilayer conditions. Although the study primarily focuses on using RAP as the investigated material, the methodology developed in this study can be applied to any type of unbound aggregate as demonstrated in this study.

Asphalt Elasticity Modulus Comparison Using Modified Laboratory LWD Against UMMATA Method

“…This results in a variation in the computed ELWD values. A typical LWD device has a loading plate with a diameter of 100 to 300 mm and a drop weight of 10 to 20 kg, an accelerometer or geophone to measure deflection, and a load cell or load limit calibrated to measure the plate contact stress [29].…”