Studying the parameters involved with modulus-based construction quality control for compaction of unbound pavement layers

Mehran Mazari, University of Texas at El Paso


Pavement performance is impacted by several factors such as the properties of the materials, combination of traffic and loading, structural capability, climate changes and construction process. Earthwork and unbound materials is an important part of pavement constructions since most of the distresses can be related to these geomaterials. Appropriate process control, proper processing of geomaterials, adequate amount of moisture and suitable compaction effort would ensure the required density and stiffness of the compacted pavement layer. The Nuclear Density Gauge (NDG) has been the primary means of Quality Control and Quality Acceptance (QC/QA) by State Highway Agencies (SHAs) and department of transportations (DOTs) for many years. Although the difference in compacted layer moisture content at the time of testing with the moisture at the time of compaction plays an important role in stiffness of compacted geomaterials, most highway agencies have not been considered that in the construction quality control. Furthermore, measurement of moisture content and dry density, even though quite practical and straightforward, does not tie the construction with the design process where mechanical properties (as reflected in both AASHTO Pavement Design Guide and the Mechanistic Empirical Pavement Design Guide) such as stiffness and modulus were employed. Such transformation from density-based to modulus-based QC/QA approach has involved with some technical and organizational difficulties. In order to obtain high-quality pavement layers with long lasting performance, the reasons for such complications should be understood and promoted through complimentary laboratory and field investigations. Efficient and applicable control process should also be proposed alternatively. Recent advances emerged the use of in-situ Non-Destructive Testing (NDT) devices which adequately estimate the stiffness parameters of a constructed pavement structure. Such structural parameters are more representative of the pavement performance predicted during the empirical-mechanistic design process.

Subject Area

Civil engineering

Recommended Citation

Mazari, Mehran, "Studying the parameters involved with modulus-based construction quality control for compaction of unbound pavement layers" (2014). ETD Collection for University of Texas, El Paso. AAI3636287.