Edge Drain Performance

Edge drain systems are used on new highway construction projects and rehabilitation projects to reduce the moisture content of the pavement block and subgrade. Maintaining dry conditions in and around these components increases the subgrade strength and extends a pavement’s surface life. Edge drain systems can only operate effectively, however, if the entire subsurface drainage system functions properly. While many studies have demonstrated the benefits of edge drain systems, no comprehensive investigation of their performance has been undertaken in the state of Kentucky in over 20 years. After the Kentucky Transportation Cabinet (KYTC) identified problems with an edge drainage system along a segment of Interstate 275 in Kenton County, the agency commissioned researchers at the Kentucky Transportation Center (KTC) to evaluate the performance of edge drains on roadway segments that will be resurfaced in the coming years. Researchers comprehensively inspected 10 roadway segments, assessing several components of their edge drain systems. For edge drain systems with headwalls, researchers found that all headwalls (n =126) were in good condition and free of structural issues. Roughly 29% of the outfall waterways prevented the flow of water from the headwall, while 65% of the outlet waterways were blocked to some extent by gravel, mud, silt, or other debris, and 61% of the outlet pipes were obstructed. Of the edge drain systems draining to catch basin inserts or ditch bottom inlets (n = 110), outfall waterways were clear on 97% of the systems, but just 14% of the edge drains were unobstructed. Based on inspections, edge drain systems were classified as good, compromised, or undetermined (the final designation being used if conditions prevented a full inspection) and identified a probable failure mode. Approximate 75% of the problems found during inspections were related to maintenance, with the remainder the product of construction activities. To preserve edge drains in a functional condition, post-installation inspections should be conducted, and yearly inspections and cleanings of headwalls and outlet pipes completed. Other methods for outletting water (e.g., dry wells) can also be explored

Forensic Pavement Evaluation for US 31 W, Jefferson County, Kentucky Using Ground Penetrating Radar

The Kentucky Transportation Center (KTC) utilized ground penetrating radar technology to provide a forensic evaluation of the existing pavement structure for the US31W pavement rehabilitation Project in Jefferson County, KY. Processed ground penetrating radar data indicated that the integrity of the underlying concrete pavement beneath the asphalt pavement appears to be competent and structurally sound. The clay soil beneath the concrete pavement appears relatively dry and well compacted. The analyzed GPR data also indicated that the average asphalt layer varied by lane throughout the project from 4.89 to 7.59 inches +/- ½ inch and that the underlying concrete layer average varied by lane throughout the project from 6.59 to 8.12 inches +/- ½ inch. This information was shared with design engineers in efforts to select the most appropriate pavement rehabilitation repair

Determination of Constructed Pavement Layer Thicknesses Using Nondestructive Testing (NDT)

Using nondestructive testing (NDT) to measure the thickness of pavement layers can improve the overall life of a new concrete and/or asphalt pavement. Conventional test methods require the extraction of a core from the pavement section to verify its thickness. Currently, two NDT technologies are commercially available which eliminate or reduce the need to core the existing pavement for thickness verification. The MIT-Scan-T2 (T2) utilizes magnetic pulse induction coupled with preset metal plates to obtain a thickness value. Measurements can be obtained quickly to an accuracy of +/– 2 mm. Ground Penetrating Radar (GPR) uses electromagnetic radiation to determine pavement layer thickness. However, GPR data need to be calibrated with an actual core during the post-processing phase to obtain the highest accuracy. Additionally, the dielectric properties of pavement sections being assessed with GPR must first stabilize to accurately measure thickness. Generally, stabilization occurs approximately 28 days after the initial placement of the pavement

AID Project Summary Report for Intelligent Compaction

This study reviews data from five roadway construction projects on which intelligent compaction (IC) techniques were used to achieve the more uniform compaction of road-building materials. Kentucky Transportation Center (KTC) researchers looked at IC data collected from these projects — resulting in the production of eight analyzable data sets — to determine whether they complied with the special construction note included in contract documents. The report also compares the intelligent compaction measurement value (ICMV) collected on each project to traditional laboratory results. Researchers used Veta software to analyze geospatial data collected from IC machines during construction work. Of the data sets, three indicated the required minimum coverage pass count had been achieved, although these did not attain the required minimum coverage for ICMV. Three other data sets achieved minimum ICMV coverage, while the final two data sets did not reach minimum coverage for either metric. Regression analysis found no meaningful relationship between density and ICMV. Attention is also paid to challenges which arose during the review of IC data and feedback received from contractors about the use of IC. Contractors appreciate that IC is able to transmit real-time data to operators and provides access to the mat temperature, however they observed inconsistencies with the ICMV for mill/fill projects and on new construction. These inconsistencies are the product of several factors, including cuts, fills, soil types, and the amount of water in the roller. A special construction note with instructions for using IC on Federal-aid projects is included as well. It specifies materials and equipment requirements, contractor responsibilities, construction methods, payment, and performance measures

Sloped and Mitered Concrete Headwalls

The Kentucky Transportation Cabinet (KYTC) currently uses several pipe culvert end treatments, including standard headwalls, slope and flared headwalls, sloped and parallel headwalls, and safety metal ends. These treatments, however, can pose a safety hazard to motorists and those performing landscaping work (e.g., mowing). Crash statistics from 2012 through 2016 for Kentucky reveal that 49 fatalities and 148 incapacitating injuries occurred in incidents where culverts/headwalls were coded as the first harmful event on the police report. One solution to the safety hazards associated with standard pipe culvert headwalls is to use sloped and mitered concrete headwalls instead. To evaluate the viability of sloped and mitered concrete headwalls for widespread use, Kentucky Transportation Center (KTC) researchers reviewed industry guidance and best practices; observed, documented, and analyzed several projects on which sloped and mitered concrete headwalls were used; developed cost comparisons for sloped and mitered concrete headwalls and conventional headwalls, and evaluated specifications for sloped and mitered concrete headwalls adopted by other states. Sloped and mitered concrete headwalls conform with industry guidance and protect against significant vehicle damage. Observations of sloped and mitered concrete headwalls used on KYTC projects attested to the importance of establishing and applying unambiguous design and construction criteria. Specifically, the grade should be set before a slope and mitered headwall is installed. Furthermore, adding grate bars will improve performance as will securing pipe ends to the headwall. A sample of headwalls should be chosen for long-term monitoring purposes, with inspections conducted each year. Overall, sloped and mitered concrete headwalls are an attractive option given they can be installed quickly and without special equipment, their robust performance, and low cost compared to standard pipe culvert headwalls

Can sand dunes be used to study historic storm events?

Knowing the long-term frequency of high magnitude storm events that cause coastal inundation is critical for present coastal management, especially in the context of rising sea levels and potentially increasing frequency and severity of storm events. Coastal sand dunes may provide a sedimentary archive of past storm events from which long-term frequencies of large storms can be reconstructed. This study uses novel portable optically stimulated luminescence (POSL) profiles from coastal dunes to reconstruct the sedimentary archive of storm and surge activity for Norfolk, UK. Application of POSL profiling with supporting luminescence ages and particle size analysis to coastal dunes provides not only information of dunefield evolution but also on past coastal storms. In this study, seven storm events, two major, were identified from the dune archive spanning the last 140 years. These appear to correspond to historical reports of major storm surges. Dunes appear to be only recording (at least at the sampling resolution used here) the highest storm levels that were associated with significant flooding. As such the approach seems to hold promise to obtain a better understanding of the frequency of large storms by extending the dune archive records further back to times when documentation of storm surges was sparse

Longer Lasting Bridge Deck Overlays

The objective of this report is to determine the most effective method for bridge deck overlay construction and repair by assessing current practices; examining new products and technologies; and reviewing NCHRP (National Cooperative Highway Research Program) guidelines, state standard specifications, ASCE (American Society of Civil Engineers) infrastructure ratings, and original bridge core chloride penetration data. Based on the review, this report offers the following conclusions. Latex modified concrete (LMC) overlays perform well, provide a long service life, and are the most commonly used method of bridge deck rehabilitation. Ohio considers microsilica concrete (MSC) overlays as state of the art due to their lower permeability. Superplasticized dense concrete (SDC), fly-ash modified concrete (FAMC), and polymer modified concrete (PMC) are other acceptable choices for bridge deck overlays. Silane or epoxy sealers may be used as a low-cost preventative approach to slow the deterioration of concrete bridge decks. Waterproofing membranes have produced mixed results but have the potential to be an effective system if installed correctly. Rosphalt® can be an expensive material but offers benefits such as minimizing traffic disruption due to shorter installation periods and increased durability. The two most important conclusions drawn from this research are the importance of a comprehensive approach when selecting a bridge deck rehabilitation method, and the importance of properly following instructions when installing overlays or waterproofing membrane systems

Non-linear model equation for three-dimensional Bunsen flames

The non linear description of laminar premixed flames has been very successful, because of the existence of model equations describing the dynamics of these flames. The Michelson Sivashinsky equation is the most well known of these equations, and has been used in different geometries, including three-dimensional quasi-planar and spherical flames. Another interesting model, usually known as the Frankel equation,which could in principle take into account large deviations of the flame front, has been used for the moment only for two-dimensional expanding and Bunsen flames. We report here for the first time numerical solutions of this equation for three-dimensional flames

Flame front propagation IV: Random Noise and Pole-Dynamics in Unstable Front Propagation II

The current paper is a corrected version of our previous paper arXiv:adap-org/9608001. Similarly to previous version we investigate the problem of flame propagation. This problem is studied as an example of unstable fronts that wrinkle on many scales. The analytic tool of pole expansion in the complex plane is employed to address the interaction of the unstable growth process with random initial conditions and perturbations. We argue that the effect of random noise is immense and that it can never be neglected in sufficiently large systems. We present simulations that lead to scaling laws for the velocity and acceleration of the front as a function of the system size and the level of noise, and analytic arguments that explain these results in terms of the noisy pole dynamics.This version corrects some very critical errors made in arXiv:adap-org/9608001 and makes more detailed description of excess number of poles in system, number of poles that appear in the system in unit of time, life time of pole. It allows us to understand more correctly dependence of the system parameters on noise than in arXiv:adap-org/9608001Comment: 23 pages, 4 figures,revised, version accepted for publication in journal "Combustion, Explosion and Shock Waves". arXiv admin note: substantial text overlap with arXiv:nlin/0302021, arXiv:adap-org/9608001, arXiv:nlin/030201