In 2009, MaineDOT constructed a porous asphalt pavement on a high-volume public road, which was the first application in the Northeastern United States. The porous pavement system was selected as a mitigation technique for Long Creek Watershed. The pavement design included a filter layer, reservoir stone layer, asphalt treated permeable base (ATPB), and open graded friction course (OGFC). Thermocouples were installed at different depths to monitor the temperature variations, especially during cold weather. The performance of the pavement was measured using visual distress surveys at three intervals over ten years, along with periodic automated distress surveys. This case study presents the design, construction, and performance aspects of this porous asphalt pavement. A conventional reconstruction project and a mill & fill project constructed in the same year were considered for comparative performance analysis. Overall, after ten years, the porous pavement is relatively free of distress except for localized areas of raveling. The evaluations noted the impact of tracking and build-up of debris and sand to the OGFC surface layer, so maintenance of the porous pavement is considered crucial. The porous asphalt pavement shows similar levels of distress when compared to a conventional asphalt pavement project. MaineDOT is satisfied with the performance of the porous pavement; both in its ability to handle stormwater runoff and to provide a safe and durable surface for travelers.

Numerous studies have been conducted to identify moisture sensitive mixes during mix design by simulating various mechanisms of moisture damage. These methods involve the determination of changes in strength or stiffness of asphalt mixes due to moisture conditioning. The objective of this study is to understand the coupled problem of moisture induced material loss and change in strength/stiffness of the mix. Moisture Induced Stress Tester was used for conditioning samples of a poor and a good performing mixes. This test applies cyclic pressures in the asphalt mix samples through repeated pulses of water. The effluent containing aggregates and binder that were dislodged from the samples during the moisture conditioning process were collected for testing. Both coated and uncoated/fractured aggregates were found in the effluent. The results indicated that the samples with a higher loss of asphalt binder compared to other samples in the investigation during conditioning may exhibit higher tensile strengths, and those with a loss of finer materials, which is indicative of aggregate breakdown, show a lower tensile strength. Both seismic modulus and indirect tensile strength tests were found to be able to differentiate the poor and good performing mixes. For the mixes used in this study, the rate of change in indirect tensile strength during moisture conditioning was found to be strongly correlated to the pre-conditioning modulus of the mix, and a method is suggested for using the threshold values of properties of pre-conditioning mixes for different durations of moisture conditioning during mix design to screen poor mixes in a fast and nondestructive manner.

Crack sealing is an important preventive treatment in the pavement preservation program. To achieve a cost-effective crack seal, it is crucial to select a proper crack sealing method. In Minnesota asphalt pavement cracks are sealed using both the clean-and-seal and rout-and-seal methods; however, there is no guideline for choosing the most suitable crack sealing method. This study deals with a literature review, an online survey, crack seal performance data collection, cost-effectiveness analysis of the crack sealing methods, life cycle cost analysis, and development of two decision trees to aid in selecting the most suitable crack sealing method. The first, which can be used in the pavement management system, needs information such as crack severity, pavement type (new versus overlay), pavement analysis period and design life, traffic level, and crack seal sequence (first, intermediate, or last). The second decision tree, which is a simplified version of the first and can be used by preventive maintenance crews, requires less information, such as crack severity, traffic level, and place in the crack sealing sequence.

To date, most of the studies to evaluate moisture susceptibility of hot mix asphalt have been carried out by quantifying the degradation of the mix properties due to conditioning that simulates the action of moisture in the field. There is a need for research on the identification of moisture susceptible mixes which show the material loss in the wheel-path under the combined action of traffic and moisture. The objective of this study was to simulate and analyze the moisture induced material loss, and also to identify a mix with the potential of moisture induced material loss that has shown damage in the field but not under regular testing in the laboratory. The Moisture Induced Stress Tester (MIST), Ultrasonic Pulse Velocity (UPV), Dynamic Modulus in Indirect tensile mode, Indirect Tensile Strength (ITS), and Model Mobile Load Simulator (MMLS3) tests were utilized in the study. The effluent from the MIST was checked for the gradation of dislodged aggregates and the Dissolved Organic Carbon content. The results from the effluent analysis showed the loss of material and aggregate breakage from a moisture susceptible mix. A similar type of losses from the mix was also evident from MMLS3 loading under wet-hot conditions. The results of the mix mechanical properties showed that the use of MIST in combination with UPV or ITS is ab le to identify moisture susceptible mixes, in particular for mixes with the potential of aggregate breakage.