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1 SUMMARY NDT Technology for Quality Assurance of HMA Pavement Construction Introduction Quality assurance (QA) programs provide the owner and contractor a means to ensure that the desired results are obtained to produce high-quality, long-life pavements. Desired results are those that meet or exceed the specifications and design requirements. Traditional pavement construction quality control and quality acceptance (QC/QA) procedures include a variety of laboratory and field test methods that measure volumetric and surface properties of pavement materials. The test methods to measure the volumetric properties have changed little within the past couple of decades. More recently, nondestructive testing (NDT) methods, including lasers, ground-penetrating radar (GPR), falling weight deflectometers (FWD), penetrometers, and infrared and seismic technologies have been improved significantly and have shown potential for use in the QC/QA of flexible pavement construction. Furthermore, the new Mechanistic-Empirical Pavement Design Guide (MEPDG) uses layer modulus as a key material property. This should lead to increased measurement of layer moduli--a material property that can be estimated through NDT tests, which is not included, at present, in the acceptance plan. This research study investigated the application of existing NDT technologies for measuring the quality of flexible pavements. Promising NDT technologies were assessed on actual field projects for their ability to evaluate the quality of pavement layers during or immediately after placement or to accept the entire pavement at its completion. The results from this project identified NDT technologies ready and appropriate for implementation in routine, practical QC/QA operations. Objectives The overall objective of NCHRP Project 10-65 was to identify NDT technologies that have immediate application for routine, practical QA operations to assist agency and contractor personnel in judging the quality of hot mix asphalt (HMA) overlays and flexible pavement construction. This objective was divided into two parts: 1. Conduct a field evaluation of selected NDT technologies to determine their effectiveness and practicality for QC/QA of flexible pavement construction. 2. Recommend appropriate test protocols based on the field evaluation and test results. Effectiveness and practicality are key words in the first part of the objective. The field evaluation plan was developed to determine the effectiveness and practicality of different