Download or read book Investigate Feasibility of GPR to Measure In place Density of New Asphalt Pavement written by Arudi Rajagopal and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Density of asphalt mixtures is one of the most important properties to monitor during construction of Hot Mix Asphalt (HMA) pavements. Many highway agencies routinely specify and measure in-situ asphalt mixture density or air void and use it as a basis for acceptance. Traditionally, density of a newly constructed asphalt concrete layer has been measured in the laboratory using randomly selected core samples extracted from finished pavement. This study investigates the applicability of Ground Penetrating Radar (GPR) for assessment of in-place density of HMA mixtures. GPR measurements were made at two ongoing construction projects in Ohio. Core samples were simultaneously collected and tested in the lab. An analytical model called the 'ALL model' proposed by the University of Illinois researchers was used to derive density values from GPR measurements. The analysis of data indicated that results from core samples and GPR measurements are statistically comparable. Based on the results obtained, it can be concluded that GPR has the potential to map the density of in-place asphalt mixtures in comparison with core densities.

Download or read book A Working Review of Available Non nuclear Equipment for Determining In place Density of Asphalt written by Shad M. Sargand and published by . This book was released on 2005 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: Current non-nuclear methods of measuring asphalt pavement density use electrical properties of asphalt. Two known instruments, the PaveTrackerTM and the PQI Model 300, estimate pavement density by inferring the relative proportion of air-filled voids in the asphalt from a measure of dielectric permittivity. Under this project, currently available and new methods of determining in-place asphalt density were investigated. The investigation included a laboratory study of the PaveTrackerTM's ability to accurately measure density under a variety of conditions, including coarse or fine aggregate in mix, presence of internal and/or surface moisture, sample area, and sample depth. Both the PaveTrackerTM and the PQI Model 300 were evaluated in the field by measuring density of measurement locations at each of 24 project sites and comparing to corresponding values measured by a nuclear gauge and laboratory tests. Recommendations for practice, including expected payoff results in using them, are given.

Download or read book Development of an Improved System for Oregon to Accurately Quantify Dense graded Hot Mix Asphalt Pavement Density written by Suraj Darra and published by . This book was released on 2010 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Oregon Department of Transportation (ODOT) standard specifications require a minimum density for the construction of dense-graded hot mix asphalt (HMA) pavements. Currently, the standard specifications call for density measurements for quality control (QC) and quality assurance (QA) testing to be made using nuclear density gauges that are calibrated using reference blocks and correlated (adjusted) to densities from pavement cores. QC measurements (performed by the contractor) are verified by QA measurements (performed by ODOT); then ODOT utilizes the contractor's QC results for determining acceptance of the pavement (in conjunction with other specification criteria). Hence, appropriately accepting an HMA pavement, based on the in-place density criterion, relies on the accuracy of the density measurements. However, density measurement results using nuclear gauges have been observed by ODOT to be questionable on a number of projects, and repeatability and reproducibility with the same gauge and between gauges has been unattainable. The overall objective of the project described herein was to develop a system that accurately quantifies density of dense-graded HMA pavements. More specifically, the objectives were to: 1) investigate the efficacy of the various methods used by ODOT and other agencies for determining in-place HMA density; 2) assess current practices used by ODOT and other agencies for determining in-place HMA density using nuclear gauges; 3) conduct field and laboratory testing and analyses to determine the most accurate and reliable state-of-the-practice means for determining in-place HMA density; 4) provide recommendations for changes to current practices to improve accuracy and reproducibility of in-place HMA density measurements using nuclear gauges; and 5) provide recommendations for alternate means for determining in-place HMA density. To satisfy the first objective, a literature review was conducted and summarized herein. For the second objective, practices employed by ODOT were observed and assessed. For the third objective, state-of-the-practice methods used to measure HMA density (i.e., tests on core samples using the saturated surface-dry and automatic vacuum sealing methods, nuclear density gauge measurements and electromagnetic density gauge measurements) were investigated. Numerous statistical comparisons of the results were made to determine the best combination of measurement methods to ensure accurate assessment of HMA density for a variety of construction scenarios. Finally, the findings from the first three objectives were used to formulate the recommendations identified in the fourth and fifth objectives. Some of the significant findings that are based on the supporting evidence from the research are as follows: 1) Nuclear gauge densities should be adjusted to core densities for future in-place density testing of HMA pavements; 2) Cores should be tested in accordance with CoreLok testing procedure and not by using the SSD methods; 3) Cores should be extracted from the overlapping portion of the footprints of the nuclear gauge measurements; 4) It is sufficient to take two nuclear gauge readings (perpendicular and parallel to the direction of paving) rather than four readings; 5) Under certain conditions, the core adjustment factors obtained from the bottom lift can be used to adjust the nuclear gauge densities on at least the next two overlying lifts of the same pavement; and 6) The electromagnetic gauge adjustment factors could be used on more lifts than nuclear gauge adjustment factors to adjust measurements; and, electromagnetic gauge densities were not significantly different from core densities.

Download or read book Ground Penetrating Radar GPR Analysis written by and published by . This book was released on 2009 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this work is to evaluate the feasibility of expanding the MDT Ground Penetrating Radar (GPR) program to a broader range of pavement evaluation activities. Currently, MDT uses GPR in conjunction with its Falling Weight Deflectometer (FWD) data collection program to provide layer thickness data for backcalculation. This program has included a review of literature and software dealing with pavement applications of GPR, a survey of state highway agency (SHA) use of GPR for pavement applications, a review of MDT's GPR program, and a review of MDT's pavement structures, environment, and pavement management and rehabilitation practices. A detailed review of 47 documented studies shows that GPR pavement thickness measurements typically fall within 2 to 10 percent of core values for the bound layers. Most of these studies have used a 1.0 GHz horn antenna (vs. the 2.0 GHz antenna currently used by MDT). Accuracy of unbound material is less precisely documented. The survey of SHA GPR practice supports the application of GPR for pavement thickness measurements; some agencies use GPR on a regular basis, while others use GPR on a project-specific basis. The application of GPR for measuring pavement network is 97 percent AC, with mostly aggregate base but some areas with cement-treated base, and maintenance is typically carried out using chip seals. Based on an evaluation of MDT's rehabilitation and reconstruction practices, it appears that the GPR program can be expanded to provide useful information for the following applications: (a) calculation of structural number for pavement reconstruction and rehabilitation design; (b) insuring proper depth control for mill and fill rehabilitation and cold-in-place recycling; (c) improved structural capacity calculation for network level evaluation; and (d) quality assurance of new pavement thickness and density. In order to investigate the feasibility and value of these program expansions, it is recommended that a field evaluation project be designed and implemented to evaluate the accuracy of GPR pavement thickness (and density) data on Montana pavements, and to correlate these findings with the accuracy requirements of the individual applications.

Download or read book Non nuclear Density Testing Devices and Systems to Evaluate In place Asphalt Pavement Density written by Robert L. Schmitt (Ph.D.) and published by . This book was released on 2006 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Investigation into nuclear measurement of asphalt pavement density written by Colorado. Department of Highways and published by . This book was released on 1962 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Base Compaction Specification Feasibility Analysis written by and published by . This book was released on 2012 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this research is to establish the technical engineering and cost analysis concepts that will enable WisDOT management to objectively evaluate the feasibility of switching construction specification philosophies for aggregate base. In order to accomplish this goal, field and laboratory testing programs were conducted on existing HMA pavements and on base layers under construction as well as comprehensive survey was conducted on highway agencies practices pertaining to base layer construction in the U.S. and Canada. This research proposed construction specifications for aggregate base course layers.

Download or read book Investigation of Electromagnetic Gauges for Determining In place HMA Density written by and published by . This book was released on 2007 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt: Density is an important component of hot-mix asphalt (HMA) pavement quality and long-term performance. Insufficient density of an in-place HMA pavement is the most frequently cited construction-related performance problem. This study evaluated the use of electromagnetic gauges to nondestructively determine densities. Field and laboratory measurements were taken with two electromagnetic gauges-a PaveTracker and a Pavement Quality Indicator (PQ1). Test data were collected in the field during and after paving operations and also in laboratory on field mixes compacted in the lab. This study revealed that several mix-and project-specific factors affect electromagnetic gauge readings. Consequently, the implementation of these gauges will likely need to be done utilizing a test strip on a project- and mix-specific basis to appropriately identify an adjustment factor for the specific electromagnetic gauge being used for quality control and quality assurance (QC/QA) testing. The substantial reduction in testing time that results from employing electromagnetic gauges rather than coring makes it possible for more readings to be used in the QC/QA process with real-time information without increasing the testing costs.

Download or read book Ground Penetrating Radar Sensitivity to Marginal Changes in Asphalt Mixture Composition written by Eyoab Zegeye Teshale and published by . This book was released on 2020 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ground penetrating radar (GPR) is gaining renewed attention from many state highway agencies because of its promising application prospects for rapid, full-coverage, continuous, and nondestructive measurements of the density in newly constructed asphalt pavements. However, several operational and technical issues need to be addressed before this technology can be efficiently deployed for quality control/quality assurance practices. The operation-related challenges are relatively easily addressed with proper project-specific management practices. The technical ones, on the other hand, require improvements to the testing devices and procedures and strategic investigations for further understanding of the relationship between the GPR-measured dielectrics and the density of asphalt mixtures. The latter is particularly crucial given the production and construction variability of asphalt mixtures and the accepted practices of field adjustments to mix designs. This study investigated the sensitivity of dielectric measurements to changes in mix composition and assessed the appropriateness (or lack thereof) of using a single dielectric-density transfer model to analyze field data measured on multiple production days. The study examined asphalt mixtures designed and manufactured in the laboratory with varying amounts of limestone, a high-dielectric aggregate source, as well as plant-produced asphalt mixtures collected on multiple production days. The findings indicated that the source/composition of the aggregate structure affected density-dielectric relationships of asphalt mixtures considerably. On the contrary, the relationship appeared to be less sensitive to normal asphalt production variability (day to day variations) as long as the aggregate source proportions were maintained intact. The experimental investigation proposed in this study can be easily employed to determine the proper amount of calibration models or the extent of allowable adjustment to the mix design for asphalt pavement construction projects.

Download or read book Density Measurement of Compacted Asphalt Mixtures Using Non destructive Ground Penetrating Radar written by Mardeni Roslee and published by . This book was released on 2009 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes the development of Ground Penetrating Radar (GPR) system based on the electromagnetic wave reflection to determine the density of road pavement. The proposed method is simple, fast, non-destructive and within an acceptable accuracy of road pavement density. The theoretical analysis based on the three existing GPR Mixture Model (GMM) methods has been improved to produce the most optimized function to be incorporated within the proposed GPR system. The study involves three main procedures which are theoretical analysis, laboratory scale experimentation and reliability analysis. From these studies, the Lichtenecker Mixture Model is found to be the most accurate function compared to the other models like Nelson and Landau due to the smallest mean error between the prediction and the experimental result. During the laboratory experimentation, an engineering GPR prototype has been developed and used to measure the road pavement density of the road pavement slab sample. The GPR to measure the road pavement density of the road pavement slab sample. The GPR system consists of the transmitter which is signal generator as a microwave source, horn antenna for transmitting and receiving the signal, directional couple with an adapter and spectrum analyzer to analyze the received signal. Nine road pavement slabs of middle boundary and ten slabs of upper and lower boundary of Hot Mix Asphalt (HMA) gradation were developed and tested at four different frequencies within the range of 1.7-2.6GHz. The predicted signal attenuation from the theoretical analysis is compared to the signal attenuation measured from the laboratory experimentation. The comparison produces the relative error between these two results and it is used in the optimization process. The finding from the optimization process suggested that three additional constant parameters which are Volume factor, Permittivity factor and Attenuation factor need to be included to improve the existing GMM model. A field test had been conducted as an outdoor reliability analysis to validate the optimized GMM model. From the field test, it shows that the proposed GPR system works well with an error range from 3.37 % to 4.72 % for nine locations. Finally, a complete GPR system has been developed based on the optimized GMM attenuation curve to predict the density of a real road pavement.

Download or read book Prototype Construction and Field Tests of the Microwave Asphalt Density Sensor written by Khim Liong Tan and published by . This book was released on 1998 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Asphalt density measurements have been traditionally used as an indication of roadway pavement quality. These measurements, however, have not been available in real time to make in-process corrections to the paving operation since the existing techniques require on the order of minutes (nuclear density gauge) to hours (core samples) to produce accurate density measurements. Traditional ground penetrating radar (GPR) techniques could also have limitations due to the changing properties of the hot mix asphalt pavement while it is being compacted. This thesis describes a novel approach to measure, for the first time, the density of asphalt in real time using a differential microwave signal approach. Two antennas, one in front of a roller and another behind it, will measure reflected signals from the asphalt; the change in signal characteristic from the front toback of the roller will show to the operator the optimal compaction and density of the pavement. This technique will minimize the need to quantify the hot mix asphalt properties that change during the compaction process. Field studies show that this approach has potential.

Download or read book Test Procedure for GPR for Asphalt Mixture Construction written by Bryan T. Wilson and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This product presents a draft test method to obtain a density profile of an asphalt paving project using ground penetrating radar (GPR). The method includes procedures for general system calibration, calibration of the GPR to the specific asphalt mixture, data collection, analysis procedures, and report summary.

Download or read book In place Hot Mix Asphalt Density Estimation Using Ground Penetrating Radar written by Imad L. Al-Qadi and published by . This book was released on 2011 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Eleventh International Conference on the Bearing Capacity of Roads Railways and Airfields written by Inge Hoff and published by CRC Press. This book was released on 2021-11-10 with total page 501 pages. Available in PDF, EPUB and Kindle. Book excerpt: Innovations in Road, Railway and Airfield Bearing Capacity – Volume 1 comprises the first part of contributions to the 11th International Conference on Bearing Capacity of Roads, Railways and Airfields (2022). In anticipation of the event, it unveils state-of-the-art information and research on the latest policies, traffic loading measurements, in-situ measurements and condition surveys, functional testing, deflection measurement evaluation, structural performance prediction for pavements and tracks, new construction and rehabilitation design systems, frost affected areas, drainage and environmental effects, reinforcement, traditional and recycled materials, full scale testing and on case histories of road, railways and airfields. This edited work is intended for a global audience of road, railway and airfield engineers, researchers and consultants, as well as building and maintenance companies looking to further upgrade their practices in the field.

Download or read book Introduction to Unmanned Aircraft Systems Second Edition written by Douglas M. Marshall and published by CRC Press. This book was released on 2015-10-26 with total page 1944 pages. Available in PDF, EPUB and Kindle. Book excerpt: The proliferation of technological capability, miniaturization, and demand for aerial intelligence is pushing unmanned aerial systems (UAS) into the realm of a multi-billion dollar industry. This book surveys the UAS landscape from history to future applications. It discusses commercial applications, integration into the national airspace system (NAS), System function, operational procedures, safety concerns, and a host of other relevant topics. The book is dynamic and well-illustrated with separate sections for terminology and web- based resources for further information.

Download or read book Report National Cooperative Highway Research Program written by and published by . This book was released on 1964 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Innovation in Near Surface Geophysics written by Raffaele Persico and published by Elsevier. This book was released on 2018-10-05 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt: Innovation in Near-Surface Geophysics: Instrumentation, Application, and Data Processing Methods offers an advanced look at state-of-the-art and innovative technologies for near surface geophysics, exposing the latest, most effective techniques in an accessible way. By addressing a variety of geophysical applications, including cultural heritage, civil engineering, characteristics of soil, and others, the book provides an understanding of the best products and methodologies modern near surface geophysics has to offer. It proposes tips for new ideas and projects, and encourages collaboration across disciplines and techniques for the best implementation and results. Clearly organized, with contributions from leaders from throughout geophysics, Innovation in Near-Surface Geophysics is an important guide for geophysicists who hope to gain a better understanding of the tools and techniques available. Addresses a variety of applications in near-surface geophysics, including cultural heritage, civil engineering, soil analysis, etc. Provides insight to available products and techniques and offers suggestions for future developments Clearly organized by techniques and their applications