Evaluation of rutting potential of hot mix asphalt using the asphalt pavement analyzer

A comprehensive study involving rut potential of Hot Mix Asphalt (HMA) was conducted. Both cylindrical and beam specimens of HMA were prepared using a Superpave Gyratory Compactor (SGC) and an Asphalt Vibratory Compactor (A VC), respectively. Mixture rutting performance was determined in the Asphalt Pavement Analyzer (AP A). Initially, rut tests were conducted on three laboratory-prepared HMA for 8000 cycles of loading with I 00 psi hose pressure, 100 lb wheel load, and 50 seating cycles. The rut values (8,000 cycles) varied between 2.0 mm and 6.4 mm. Rut depths were found to be sensitive to temperature when compared that to asphalt content. Subsequently, this study evaluated rut potential of ten plant-produced mixes. Three of these mixes were of type A and six type B insoluble and one Type C. Only one mix showed a rut depth of more than 4 mm. The A VC beam specimens showed higher rut depth compared to cylindrical specimens. The AP A rut test data were analyzed to identify the important contributing factors. Type A mixes were sensitive to percent asphalt content, where as Type B insoluble mixes were sensitive to material passing number 200 sieve. This research investigated the relationship between rheological and mechanical properties for various Oklahoma unmodified and modified binders based on the asphalt mixture's rutting performance. The tests result showed that binder's Performance Grade (PG) affects mixture performance significantly. In general, modified binder showed better performance compared to the unmodified binders. Modified binders of same PG grade did not show the same performance when test parameters were held constant. Binder's viscosity and rut factor (G'/sin8) did not show significant effects on rutting performance of both modified and unmodified binders. Linear and nonlinear regression analyses were performed to investigate the contribution of binder properties to rutting. The nonlinear regression prediction of rutting was better than the linear prediction. This study identified the most significant factors from a number of factors, which affect rut potential of HMA. Seven factors: binders PG, specimen type, test temperature, moisture, wheel load, asphalt content, and hose pressure,. each at two defined levels were incorporated in a Superpave mix. Rut tests were designed to be the elements of an experimental matrix. The matrix test results were analyzed statistically. The analysis results showed that binders PG, specimen type, test temperature, and moisture, affected a mixture's rutting performance significantly. This study developed and described a statistical procedure to design and analyze an experimental matrix of test results. This research investigated the repeatability and reproducibility of laboratory test data. An inter-laboratory study was performed on rut tests using the AP A between the 'asphalt design laboratory' at the Oklahoma Department of Transportation (ODOT) and the 'asphalt laboratory' at the University of Oklahoma (OU). The tests result showed no significant variability in the collected data from two laboratories. This study developed a rut database for future model development. The AP A rut results ofHMA materials, which were used in a road section (funded by ODOT) of the National Center for Asphalt Technology (NCAT) Test Track at Alabama, were also included in the rut database.Final Report (September 1999-September 2001)N

Field Performance Monitoring and Modeling of Instrumented Pavement on I-35 in McClain County

Phase 1 of this project was conducted to better understand the cause of pavement failure under actual traffic loading and environmental conditions. A 1,000-ft. long experimental pavement section was constructed on I-35 in McClain County and was instrumented for field data collection. The test section was designed to fail in a relatively short period of time under heavy interstate traffic. After approximately four years (from 2008 to 2012) of exposure to continuous interstate traffic and environment, the test section experienced significant rutting but no fatigue cracking. Therefore, the funding agency decided to monitor the test section for two additional years (from 2012 to 2014) as part of Phase 2 of the project. Additionally, a need for predicting distresses (i.e., rut, based on the site-specific data) using the Mechanistic Empirical Pavement Design Guide (MEPDG) software was expressed. In Phase 2 of this project, the quarterly field testing (FWD, rut measurements, roughness measurements, and crack mapping) was performed on a quarterly basis. Also, the weekly downloading of traffic data and data processing were performed to allow updating of the rut prediction models developed in Phase 1 of this study. Site-specific (Level 1) input parameters for traffic, climate and materials were developed in this study. Furthermore, the rut prediction models in the MEPDG software were calibrated using the developed input parameters and measured rut depths from the test section. Laboratory tests (Hamburg rut, four point beam fatigue, volumetric properties, etc.) were performed on the extracted samples from the test section. Moreover, the contribution of different pavement layers to total rutting was assessed by a forensic investigation involving cutting full-depth trenches at three selected locations of the test section.Final report, October 2012-December 2014N

Incentive Based Load Shedding Management in a Microgrid Using Combinatorial Auction with IoT Infrastructure

This paper presents a novel incentive-based load shedding management scheme within a microgrid environment equipped with the required IoT infrastructure. The proposed mechanism works on the principles of reverse combinatorial auction. We consider a region of multiple consumers who are willing to curtail their load in the peak hours in order to gain some incentives later. Using the properties of combinatorial auctions, the participants can bid in packages or combinations in order to maximize their and overall social welfare of the system. The winner determination problem of the proposed combinatorial auction, determined using particle swarm optimization algorithm and hybrid genetic algorithm, is also presented in this paper. The performance evaluation and stability test of the proposed scheme are simulated using MATLAB and presented in this paper. The results indicate that combinatorial auctions are an excellent choice for load shedding management where a maximum of 50 users participate

Evaluation of rutting potential of hot mix asphalt using asphalt pavement analyzer draft (original was missing pgs 19-23, 48, 49, 68-71, 82, 126-128)

Rutting of flexible pavement is a widespread problem nationally, including Oklahoma. Rutting is defined as the longitudinal depression along the wheel path due to progressive movement of materials under repeated traffic load. Recent studies have shown that rutting potential of hot mix asphalt (HMA) samples can be evaluated in the laboratory during the design phase of a project using an Asphalt Pavement Analyzer (APA). The rutting susceptibility is evaluated by subjecting HMA samples to moving wheel loads and measuring permanent deformation at selected points along the wheel path as a function of the number of loading cycle. A pressurized rubber hose is placed between the moving wheel and the HMA sample to approximately simulate traffic loading on a pavement in the field. Both rectangular beam and cylindrical samples can be used. A typical test usually involves 8,000 cycles of loading on three beam samples or six cylindrical samples or a combination. The Asphalt Vibratory Compactor (A VC) is used to prepare beam samples, while cylindrical samples are either prepared using a Superpave Gyratory Compactor or an Asphalt Vibratory Compactor. Temperature, magnitude and frequency of moving load, hose pressure and number of cycle can be varied between tests and within the same test, if so desired. Effect of moisture can also be considered by conducting a test under submerged condition. The University of Oklahoma (OU) received funding for a project (Item 2153) to procure an Asphalt Pavement Analyzer and an Asphalt Vibratory Compactor for the Ray Broce Materials Laboratory at OU. This project, funded jointly by the Oklahoma Department of Transportation (ODOT), the Federal Highway Administration (FHWA) and the Oklahoma Asphalt Pavement Association (OAPA), has two major goals: (a) exploratory testing of selected mixes to gain confidence and experience in using APA for evaluation of rut potential; and (b) establishing "baseline data" for selected mixes having low and high rut susceptibility. The following tasks were identified to accomplish the project goals: (i) Procurement and installation of AP A and A VC; (ii) Demonstration and training; (iii) Selection of mixes and collection of materials (ingredients); (iv) Preparation of sample; (v) Exploratory rut testing; (vi) Analysis of exploratory test data; (vii) Conducting tests for baseline data; (viii) Analysis of baseline data; (ix) Preparation of final report. The APA and the AVC were purchased in August 1999. A new electrical panel was installed in the Broce lab to meet the power requirements. Also, compressed air supply in the lab was upgraded to provide compressed air to both pieces of equipment. The installation was completed in September 1999. The manufacturer, Pavement Technologies, Inc. of Georgia, conducted a weeklong demonstration and training in October 1999 that involved calibration of data acquisition system (DAS) for wheel load, horizontal and vertical displacements, DAS setting for beam and cylindrical samples, operation of temperature and preset counter controllers, rubber hose replacement, rut depth measurement (both manual and automated), sample preparation using A VC, safety training, and complete rut and fatigue testing. Three mixes, one for exploratory testing and two for baseline data, were selected in cooperation with ODOT. In addition, ten plant-produced mixes were selected for testing by both the ODOT Materials Division and the OU Team for comparison of results and to address the issue of reliability. Later, another limestone superpave mix was added for extensive testing in developing baseline data. The mix design for exploratory testing of one of the mixes (3012-0APA-99037) was selected from ODOT standards and specifications for type B-insoluble mix. About sixty-four samples were tested for rutting. About half of these samples were prepared using A VC, while Superpave Gyratory Compactor ( SGC) was used for the remaining samples. Two different temperatures (60° and 64°C) and four different asphalt contents (4.5%, 5%, 5.5% and 6%) were used for this series of tests. In the initial stage, over 50 percent samples did not meet the target air void (7 ± 1 % ), particularly for samples prepared using A VC. Sample quality and air void compliance improved with time and experience of the research team. The rut values (8,000 cycles) varied between 2.0 mm and 6.4 mm and the average rut depth were found to be more sensitive to temperature than asphalt content. Although, one of the goals of exploratory testing was to address "reproducibility" of data, this goal could not be achieved partly because of the difficulties in achieving the target air void at the initial stage. Also, it became evident that rut potential evaluation using AP A is not a trivial exercise because of the complexities and difficulties involved in preparing "identical" samples and testing, particularly rut measurement (location, averaging, level of accuracy, sensitivity, etc.). This task w.as completed in June 2000. Based on discussions at the Project Panel Meeting, the project was extended in August 2000 for a year to address the following items that were not addressed in the work plan of the original proposal (Item 2153). (1) Comparison of data for the ten plant- produced mixes with the ODOT data for the same mixes and packaging ofthe data; (2) a better control on achieving the air void requirement; (3) reproducibility of test data; (4) correlation between rutting and resilient modulus, (5) density gradient analysis. An extension for one year is sought to address these issues. Addressing these issues is considered important in enriching our knowledge and confidence in AP A as a tool for performance-based testing of HMA. However, efforts during the past year have focused on the first three items, and equipment has been procured to pursue the remaining two items. Evaluation of rut potentials for ten plant-produced mixes was completed in September 2000. These mixes were selected in cooperation with ODOT Materials Division. Seven of these mixes were type B-insoluble, and three recycled asphalt materials (RAP). For each mix six cylindrical (SGC) and two beam samples were prepared and tested, giving a total of 76 samples. A majority of these samples met the target air void (7 ± 1%). The measured rut depth values varied between 1 mm and 8 mm. The rut depths form beam samples were consistently higher than the corresponding cylindrical samples. Such variations are attributed to sample geometry and rut measurement details. ODOT Materials Division has conducted rut tests using APA on the same ten plant produced mixes. These data was collected from ODOT, and compared with the corresponding data obtained by the OU Team. There was not a significant difference in measured rut depths for the same mix, therefore, additional rut tests were not conducted An effort was made sort out bad data, if there is any. Ranking of these mixes according to their rut potential was completed in December 2000. ODOT participated in the NCAT Test Track project and provided materials and mix designs for two test sections. Tn a meeting, the Oklahoma Asphalt Task Force suggested that the OU Broce Lab participate in rut testing of both mixes. We tested 12 samples (6 SGC cylindrical) x 2 mixes) for rutting. The rut depth from the track will be compared with the AP A data when the field data becomes available. Two gravel mixes (301 l-OK99-63070 and 30I l-OK99-63071) were selected, in cooperation with ODOT, for the development of "baseline data." For each of the two mixes, we tested 24 samples for rutting (1 gradation x I-PG binder x I-aging x I-temperature x 4 asphalt contents x 6 samples (4 SGC cylindrical samples and 2 AVC beam samples). At that stage, it was possible to prepare HMA samples to target air voids fairly accurately. Several samples were tested under wet condition and with different loading conditions as well as hose pressure. The baseline data can be used for calibration of AP A As such, the baseline data are reproducible. Since it is very difficult to produce AP A samples that are identical, addressing the issue of reproducibility is a difficult task. With significant experience over the past years in using AP A and A VC for evaluation of rutting, a duplicate series of tests (24 samples) were conducted to address reproducibility. Later, it was realized that the baseline data was lacking Superpave mixes, so a limestone mix designed in accordance with the superpave method was added with the test matrix. The limestone mix was designed using 13 different asphalt binders (unmodified and modified) that are currently used in Oklahoma. A total of I 04 cylindrical SGC samples were prepared and tested for rutting, and the results statistically analyzed to enrich the baseline database. Twelve Superpave samples were prepared in OU laboratory. Half of these samples were tested for rutting at OU, while the remaining half will be tested at ODOT. Similarly, another 12 samples were prepared at ODOT using the same aggregate and binders used at OU. The rut test values thus obtained was compared to address the issue of repeatability and reproducibility.June, 2002N

Development and Application of a Rut Prediction Model for Flexible Pavement

A four-layer neural network (NN) was constructed and applied to determine mapping associating factors in the design and testing of asphalt samples with their performance in repetitive rutting tests. A total of 1,586 samples (two samples per data point) were tested to determine rutting with the use of an asphalt pavement analyzer. Test results and mix volumetric properties were used to train the NN model. Preprocessing and principal component analysis were used, and the network was trained with the Levenberg–Marquardt algorithm. With randomly generated weighting factors to initialize the training algorithm, histograms were compiled, and outputs were estimated. Excellent agreement was observed between simulations and test data. The developed NN was used to estimate the optimum asphalt content of a Superpave® mix, and the results were satisfactory. The developed NN model will be a useful tool in the study of asphalt construction and wear

Parents’ prejudices or own religious orientation of Pakistani children : determinants of achievement-related prejudices for opposite gender and sect and their relation with mental health

The present study examined the role of parents’ prejudices and their children’s own religious orientation in the formation of children’s prejudices against the opposite gender and sect. A total of 280 children including 104 (36%) girls were recruited from various schools. Children age range from 12 to 18 years with mean ± SD = 14.60 (1.42) years. Parents of the children (including 175 fathers and 113 mothers) were approached at their homes. Based on the conceptualisation of the study, parallel models addressing gender and sectarian ingroup-outgroup classification were developed and estimated. The study tested, confirmed, and validated the cognitive-developmental model addressing the underlying mechanism for shaping the religious orientation of children as a consequence of parents’ prejudices and its role in the mental health of children. The results supported the conceptual model of the study elaborating on the underlying mechanism of the relationship among parents’ and children’s prejudices, and children’s religious orientation in the development of depression and anxiety in children. Suggestions for further research are provided

Solid-State Solar Cells Based on TiO2 Nanowires and CH3NH3PbI3 Perovskite

Perovskite inorganic-organic solar cells are fabricated as a sandwich structure of mesostructured TiO2 as electron transport layer (ETL), CH3NH3PbI3 as active material layer (AML), and Spiro-OMeTAD as hole transport layer (HTL). The crystallinity, structural morphology, and thickness of TiO2 layer play a crucial role to improve the overall device performance. The randomly distributed one dimensional (1D) TiO2 nanowires (TNWs) provide excellent light trapping with open voids for active filling of visible light absorber compared to bulk TiO2. Solid-state photovoltaic devices based on randomly distributed TNWs and CH3NH3PbI3 are fabricated with high open circuit voltage Voc of 0.91 V, with conversion efficiency (CE) of 7.4%. Mott-Schottky analysis leads to very high built-in potential (Vbi) ranging from 0.89 to 0.96 V which indicate that there is no depletion layer voltage modulation in the perovskite solar cells fabricated with TNWs of different lengths. Moreover, finite-difference time-domain (FDTD) analysis revealed larger fraction of photo-generated charges due to light trapping and distribution due to field convergence via guided modes, and improved light trapping capability at the interface of TNWs/CH3NH3PbI3 compared to bulk TiO2

Molecular identification of Anopheles (Cellia) sundaicus from the Andaman and Nicobar islands of India

Anopheles (Cellia) sundaicus (Rodenwaldt) is an important malaria vector in the Andaman and Nicobar islands of India where it breeds in freshwater as well as in brackish water. To establish the molecular identity of An. sundaicus on these islands we analyzed samples from four geographically isolated areas-Teressa, Nancowry, Car Nicobar and Katchal islands. PCR-amplification and nucleotide sequence analysis were performed for internal transcribed spacer 2 (ITS2) and domain-3 (D3) of 28S rRNA. The ITS2 region of An. sundaicus from all four islands was identical but different from An. sundaicus A of Vietnam and An. sundaicus s.s of Malaysia. Furthermore, freshwater and brackish water forms of An. sundaicus did not reveal any sequence variation. Similarly, the D3 sequences were identical among all An. sundaicus samples from the four islands. D3 sequences for a species of the Sundaicus Complex are reported here for the first time and thus could not be compared with other regional isolates of this species. In conclusion, probably only one member of the Sundaicus Complex exists on the Andaman and Nicobar islands, which breeds in freshwater as well as in brackish water and is different from the An. sundaicus A and Malaysian An. sundaicus s.s. The identification of a new sibling species of the Sundaicus Complex in these islands is significant from the viewpoint of vector control strategies

PCR-RFLP method for the identification of four members of the Anopheles annularis group of mosquitoes (Diptera: Culicidae)

The Anopheles annularis group of mosquitoes is widely distributed in Southeast Asia and may be locally important as malaria vectors. Members of this group are morphologically very similar and often difficult to distinguish, particularly A. nivipes and A. philippinensis. We report the sequence analysis of the rDNA internal transcribed spacer 2 (ITS2) and Domain-3 (D3) regions of the four members of the A. annularis group-A. nivipes, A. philippinensis, A. annularis and A. pallidus-and a method for their molecular identification. No intraspecies sequence variation was detected among the specimens, while interspecific sequence differences were greater for ITS2 than the D3 regions. Comparison of the D3 sequences of the four species revealed two SmaI restriction sites in A. nivipes, but only one site in A. philippinensis, A. annularis and A. pallidus. The ApaI site was present in both A. philippinensis and A. pallidus, while an NcoI site was present in A. pallidus only. Restriction digestion of the PCR products of D3 fragment individually with SmaI, ApaI and NcoI produced a distinctive pattern for all the four species. We present, for the first time, a PCR-RFLP method to distinguish the four members of the A. annularis group of mosquitoes

Identification of two cryptic species in the Anopheles (Cellia) annularis complex using ribosomal DNA PCR-RFLP

Anopheles (Cellia) annularis Van der Wulp is a complex of two sibling species provisionally designated as species A and B and can only be differentiated on the basis of the paracentric inversion in the ovarian polytene chromosomes. To analyze the distribution of these two species and to develop a molecular method for the identification of these two cryptic species, we sequenced the ribosomal DNA internal transcribed spacer 2 (ITS2) and domain 3 (D3) of A. annularis specimens collected from Sonapur (Assam), Jabalpur (Madhya Pradesh), Ranchi (Jharkhand), and Ghaziabad (Uttar Pradesh). We did not find any sequence variation among the specimens collected from Assam, Madhya Pradesh, and Jharkhand states, whereas two types of sequences were obtained from the specimens collected from the state of Uttar Pradesh, which correspond to species A and B of the A. annularis complex. Species A was more prevalent among the all four regions studied. The ITS2 sequence of species A showed unique restriction sites for MvaI and Eco24I, while species B displayed HinfI and NruI sites. Similarly, the D3 sequence of species A showed unique restriction site for Alw26I, while species B showed a unique KpnI site. In this study, we report for the first time the development of ribosomal DNA polymerase chain reaction-restriction fragment length polymorphism methods for identifying these two cryptic species of the Annularis complex