Intelligent Compaction (IC) of subgrade soil has been proposed to continuously monitor the stiffness of subgrade during its compaction. Modern IC rollers are vibratory compactors equipped with (1) an onboard measuring system capable of estimating the stiffness of the pavement material being compacted, (2) Global Positioning System (GPS) sensor to precisely locate the roller, and (3) an integrated mapping and reporting system. Using IC, the roller operator is able to evaluate the entire subgrade and address deficiencies encountered during compaction. Continuous monitoring of quality during construction can help build better quality and long-lasting pavements. However, most of the commercially available IC rollers report stiffness in terms of Original Equipment Manufacturer (OEM) specified indicator, known as Intelligent Compaction Measurement Value (ICMV). Although useful, additional tests are required to establish the correlation between these ICMV values and the resilient modulus of subgrade (M_r). Since the mechanistic design of the pavement is performed usingM_r, it is important to know if the designM_ris achieved on the entire subgrade during compaction. This paper presents a systematic procedure for monitoring the level of compaction of subgrade in real time using intelligent compaction (IC). Specifically, the Intelligent Compaction Analyzer (ICA) developed at the University of Oklahoma was used for estimating the modulus of the subgrade. Results from two demonstration studies show that the ICA is able to estimate subgrade modulus with an accuracy that is acceptable for quality control activities during the construction of pavements.

Compaction is one of the important steps in pavement construction that significantly affects the quality and long-term performance of asphalt pavement. Compaction of asphalt pavement is influenced by several factors related to the environment and the properties of asphalt mixture. Therefore, continuous control of compaction effort is needed in order to obtain adequate density uniformly throughout the pavement. Limited understanding of compaction dynamics and lack of a computationally tractable mathematical model hamper the development of such continuous feedback control technologies. In this paper, a lumped element-based dynamical model is developed to study the interaction between a moving vibratory roller and the underlying asphalt pavement. The asphalt pavement is represented as a collection of blocks of mechanical elements with viscoelastic-plastic properties. The vibration of the roller drum, its movement along the pavement, and its interaction with the asphalt mix is formulated. The effect of pavement temperature, layer thickness, loading frequency, and volumetric properties of asphalt mix on the mechanical behavior of the pavement is incorporated in the model. A procedure is then presented to estimate the parameters of the model from a standard laboratory complex modulus test. The model is used to numerically simulate the compaction of two different types of asphalt mixes and the results are compared with the corresponding results observed during field compaction. Analysis of the results shows that the proposed model can emulate the vibratory response of the drum observed during field compaction. The results also indicate that the model is able to replicate the pass-by-pass densification process during field compaction.

Bonded concrete overlays on asphalt pavement (BCOA) offer a rehabilitation method for moderately distressed asphalt pavements. A performance review of the BCOA projects constructed in different parts of the United States suggests that the main distresses, such as longitudinal and corner cracks, develop primarily as a result of debonding of the asphalt layer from the concrete overlay. Debonding, which reduces the contribution from the underlying asphalt layer, increases the stress in the concrete layer, leading to the development of cracks. In this study, a finite-element analysis was performed to investigate the influence of the interface bond on the load-induced stress for 76-mm (3-in.), 102-mm (4-in.), and 152-mm (6-in.) concrete overlays. It was found that debonding can increase the magnitude of the load-induced stress in the concrete by up to 40–55%. Maintaining high joint load transfer efficiency (LTE) reduces the tensile stress at the interface that contributes to debonding. Relationships were developed between LTE and debonding stress for a range of overlay designs. The findings from this study can be used to facilitate the integration of debonding models in the mechanistic-empirical design procedure for BCOA. The results from this investigation can also be used in establishing a reasonable range of the target values for interface bond strength needed when constructing BCOA to ensure good performance.

Structural fibers contribute to the overall performance of concrete pavements by mitigating various distresses. To understand the influence of structural fibers on the pavement structural responses and distresses, the Minnesota Department of Transportation (MnDOT) constructed two ultra-thin (3 and 4 in. thick) and three thin (5 and 6 in. thick) fiber reinforced concrete cells along with one plan concrete control test cell at the Minnesota Road Research (MnROAD) facility in 2017. These test cells have 6 ft x 6 ft concrete slabs and were constructed on the granular base layer. While the structural designs of these cells were intended for roads with low to moderate traffic volume, the cells were subjected to accelerated loading to complete the study in a short period of time. This paper summarizes the design and construction of the six test cells and provides a comprehensive discussion on the joint performance behavior and transverse joint faulting trends, emphasizing the influence of the fibers on the abovementioned. It was found that fibers can improve joint performance and decrease faulting in thin concrete pavements. Regarding the ultra-thin pavements, no conclusion was possible to be drawn on the contribution of the fibers.