2013 Session: 460

• Characteristics of Flow in Porous Pavements and Porous Friction Courses
  Abstract: Porous pavements (PP) and porous friction courses (PFC) are increasingly recognized as viable alternatives to traditional impervious pavements. Porous pavements and PFCs passively provide safety, hydrologic and water treatment benefits. These benefits are a result of such porous mediums providing hydraulic conveyance capacity and filtration of particulate matter (PM) transported by rainfall-runoff. With respect to 1) hydrology, these porous mediums re-introduce infiltration, evaporation and storage phenomena; 2) traffic and road safety, increase skid resistance in wet conditions, reduce hydroplaning, reduce splash and spray phenomena; and 3) water treatment, function as a filter for PM and PM-bound constituents. These phenomena and the models thereof are a function of the hydrodynamics within the porous medium (which are not necessarily laminar) and commonly characterized using the hydraulic conductivity of the porous medium. Within the scope of this study the measured hydraulic conductivity (permeability) of 12 common porous asphalt mixes were examined. As is common for PP and PFCs, a Darcian model for the hydraulic conductivity in the laminar regime of flow was examined. However during testing, hydrodynamic regimes in porous asphalt that extended beyond the laminar regime were identified for these porous mixes. Therefore, the variability of the hydraulic conductivity as a function of applied hydraulic head within a hydrodynamic regime (as quantified by the Reynolds number) was measured and modelled. From these results a saturated seepage model valid for the laminar and transitional regimes has been developed. Implications for the application of standardized permeameter for such porous mix designs are reported
  Authors: Ranieri, Vittorio; Colonna, Pasquale; Sansalone, John Joseph
  Authors: Ranieri, Vittorio; Colonna, Pasquale; Sansalone, John Joseph
  Year: 2013
  Document Type: Paper
  Subject: Geotechnology; Pavements
  Session: 460
  Paper Number: 13-2173
• Numerical Modeling of Retrofit Underdrains in Pavement Rehabilitation and Reconstruction: Case Study
  Abstract: This study focused on rainfall infiltration into pavement and water movement in the permeable base and retrofit underdrain of pavement by means of numerical simulation. The pavement examined was a new asphalt pavement section with an underdrain retrofit after reconstruction and an asphalt overlay on the top of a Crack and Seated (C & S) jointed reinforced concrete pavement with underdrain retrofit after rehabilitation on SR-49, Indiana. In order to provide highway engineers with a methodology to analyze water migration and drainage into pavement systems, a finite-element model of the pavement was developed and a number of numerical analyses were performed to evaluate the movement of water in the pavement using the SEEP/W 2004 program. Unsaturated flow analysis was used to obtain the flow path of the infiltrated water and flux quantity through a cross-sectional area in the pavement. The performance of the underdrain system was evaluated considering various levels of precipitation, cracks, permeable base and underdrain, and subgrade Soil–Water Characteristic Curves (SWCC). The findings of this research revealed that pavement sections without cracks on the surface can still accommodate approximately 20-60 percent of the rainfall volume. How much water actually infiltrates into the pavement depends on the rainfall type, and an edge drain can easily outflow most water within a few hours if the underdrain is in good condition. Therefore, the infiltration of water into the pavement structure should be addressed when designing pavement. When pavement is rehabilitated, an HMA overlay C& S JPCP layer in conjunction with a retrofit underdrain can function as an efficient method for subsurface drainage. Therefore, the infiltration of water into the pavement structure should be considered when designing pavement. In addition, this study shows that a newly-constructed full-depth asphalt with a drainage layer can also provide excellent drainage. Pavement underdrainage should be considered in planning future reconstruction and rehabilitation projects.
  Authors: Ji, Yigong; Nantung, Tommy E.; Qi, Qi
  Authors: Ji, Yigong; Nantung, Tommy E.; Qi, Qi
  Year: 2013
  Document Type: Paper
  Subject: Geotechnology; Pavements
  Session: 460
  Paper Number: 13-3704
• Numerical Modeling of Subsurface Drainage Under Concrete Pavement
  Abstract: To prevent the damaging effects of undrained moisture in pavement structures, it has become common to incorporate subsurface drainage features such as permeable bases and edgedrains into pavement design in the state of Indiana. A numerical (FEM) design methodology has been developed to ensure that the level of subsurface drainage is adequate for a concrete pavement structure. Lab tests for typical base and separate layer materials were conducted using Falling Head Testing in the course of study. Movement of water through the pavement sections was modeled using the finite element method. Two-dimensional finite element software (SEEP/W), which is capable of simulating unsaturated water flow in layered systems, was used. Precipitation recorded by an automated weather station at the monitoring site was input in the model. Numerical simulation results showed that the finite element method can be used to simulate water flow through pavement layers. Comparisons between DRIP analysis and SEEP/W analysis are provided to facilitate effective subsurface drainage design. Examples indicated that the drainage features were adequate; however, when evaluating the effectiveness of the drainage features provided, the Empirical equations in DRIP provided more conservative results compared to those obtained using the FEM approach. This research presents a more accurate assessment using FEM and proves that the current pipe size can accommodate infiltration water in Indiana. Variation of hydraulic conductivity with water content (degree of saturation), pavement geometry and dimensions, and use of subsurface drainage pipes are also important in controlling the effectiveness of a pavement subsurface drainage system. Finally, maintenance plays an important role in preserving the effectiveness of the permeable base of PCCP.
  Authors: Ji, Yigong; Nantung, Tommy E.; Qi, Qi
  Authors: Ji, Yigong; Nantung, Tommy E.; Qi, Qi
  Year: 2013
  Document Type: Paper
  Subject: Geotechnology; Pavements
  Session: 460
  Paper Number: 13-3716
• Drainage Capabilities of Nonwoven Fabric Interlayer in an Unbonded Concrete Overlay
  Abstract: Fabric interlayers have been used for the last 30 years in Germany as a bond breaker between cement treated bases and jointed concrete pavements to prevent reflective cracking and increase drainage. Recently, research has begun in the US to determine if fabric interlayers can also be used to the same effect in unbonded concrete overlays. The goal of this research was to determine the drainage capabilities of a fabric interlayer in an unbonded concrete overlay. A test slab was built in the Minne-ALF accelerated load testing facility at the University of Minnesota consisting of a five inch concrete base slab, a fabric interlayer, and a five inch concrete overlay. The transmisivity (flow velocity) and flow rate of water running through the fabric was tested under both static and dynamic conditions. Actuators were used to simulate an 18 kip axle load in the dynamic load case. The fabric interlayer was found to drain well, and exceeded the required transmisivity under both static and dynamic loading.
  Authors: Lederle, Rita; Hoegh, Kyle; Burnham, Thomas R.; Khazanovich, Lev
  Authors: Lederle, Rita; Hoegh, Kyle; Burnham, Thomas R.; Khazanovich, Lev
  Year: 2013
  Document Type: Paper
  Subject: Geotechnology; Pavements
  Session: 460
  Paper Number: 13-4107
  Practice-Ready: Yes
• Numerical Modeling of Subsurface Drainage Under Concrete Pavement
  Authors: Ji, Yigong
  Authors: Ji, Yigong
  Year: 2013
  Document Type: Presentation
  Subject: Geotechnology; Pavements
  Session: 460
  Paper Number: 13-3716
• Drainage Capabilities of Nonwoven Fabric Interlayer in an Unbonded Concrete Overlay
  Authors: Lederle, Rita
  Authors: Lederle, Rita
  Year: 2013
  Document Type: Presentation
  Subject: Geotechnology; Pavements
  Session: 460
  Paper Number: 13-4107
• Numerical Modeling of Retrofit Underdrains in Pavement Rehabilitation and Reconstruction: Case Study
  Authors: Ji, Yigong
  Authors: Ji, Yigong
  Year: 2013
  Document Type: Presentation
  Subject: Geotechnology; Pavements
  Session: 460
  Paper Number: 13-3704