bluuebunny/crossref_metadata_2025 huggingface dataset:
Simple Dynamic Hammer for Evaluation of Physical Conditions of Pavement Structures
Authors: Kongkitkul Warat , Punthutaecha Koonnamas , Youwai Sompote , Jongpradist Pornkasem , Moryadee Saravut , Posribink Thitikorn , Bamrungwong Chakree , Hirakawa Daiki
Published: July 2011

Even though low-volume roads usually serve as secondary roads on the entire road network, they are of great importance for the distribution of goods to a number of rural areas in Thailand. However, the budgets for evaluation of the physical condition of the pavement structure of roads in this category and for their subsequent maintenance are surprisingly limited. In addition, the number of specialists required to perform visual inspections is small, and simple static tests on road surfaces are time-consuming and thus expensive. Consequently, it is difficult, if not impossible, to evaluate the physical conditions of pavement structures at a sufficient number of locations. To mitigate this, it becomes necessary to develop a simple test device and a simple means of test analysis to evaluate the physical condition of the pavement structure. This paper introduces a dynamic hammer and discusses a procedure for analysis of the test data. Experiments were performed on both asphalt-paved and unpaved surfaces, which are usually used for low-volume roads. In addition, plate load tests were performed in parallel to compare the test results and validate the analytical framework. It was found that the test device and the framework for analysis of the test data presented in this paper are relevant for use, in particular because of the simplicity of device production, the ease of device use, the time-effectiveness of test performance, and the procedures used for data analysis. Therefore, maintenance can be performed at sufficient numbers of locations of low-volume roads to keep them in good physical condition for serving the entire road network.
Nine Steps to Constructing High-Quality Chip Seals
Authors: Wood Thomas J. , Olson Roger C.
Published: July 2011

If chip seals are constructed properly, they are a cost-effective means of extending the useable life of hot-mix asphalt pavements. Over the years, chip seals have been criticized because they sometimes do not perform as expected. This paper discusses the steps necessary to build chip seals that perform well, including project selection, specifications, material quality, and construction methods.
Evaluation of North Dakota's 4.75-mm Superpave Mixes for Thin Overlay Applications
Authors: Suleiman Nabil
Published: July 2011

Because of the decline in aggregate supplies and the need for durable and rut-resistant hot-mix asphalt (HMA), the use of surplus fine aggregates in 4.75-mm mixes could be beneficial for HMA producers, aggregate suppliers, and highway agencies. The primary focus of this paper is to describe the development of and evaluate 4.75-mm Superpave® mixes for use in thin overlays on non-Interstate highway pavements and maintenance applications. The asphalt pavement analyzer (APA) is used to examine the rut resistance of the 4.75-mm mixes. The acceptable APA rut depth was specified to be 9.5 mm. Because of the nature of the 4.75-mm mixes, the Superpave mix design was adjusted to avoid the production of mixes with excessive asphalt contents. A 6% air void design was crucial for the success of North Dakota's 4.75-mm mixes. The research study entailed four mix design cases involving two binders and two aggregate blends with different proportions of natural and crushed fines. Laboratory specimens were produced at 7.0% air voids, heated to either 64°C or 58°C for 6 h, and made to endure 8,000 APA loading cycles. The results indicate that all mix design cases were rut resistant and that mixes with higher percentages of crushed fines performed the best. For the design cases in which only the asphalt binder grade (PG) is the variable, the specimens were tested at different temperatures, so the results could not be compared, but a trend for an increase in rut depth with higher asphalt concrete contents was observed. Trial mixes with high percentages of natural fines failed the APA rut depth tests.
Characterization of Mechanically Stabilized Layer by Resilient Modulus and Permanent Deformation Testing
Authors: Wayne Mark , Boudreau Richard L. , Kwon Jayhyun
Published: July 2011

The majority of roadways in the United States are low volume. Pavement structures for low-volume roads (LVRs) are designed according to empirical procedures that are sometimes verified by a mechanistic-based design process. The flexible pavement structure for an LVR consists of a relatively thin asphalt–concrete wearing course and an aggregate base course constructed on subgrade. An asphalt wearing course provides a good riding surface and moisture protection for the base course. Service life of a thin asphalt pavement depends on material quality and thickness of granular layers. A compelling need now exists for reducing the cost of building and maintaining the national transportation infrastructure. The limited lifespan of most construction materials due to continuing wear and tear requires more creative, innovative, economical, and sustainable roadway design techniques. Geogrid reinforcements in LVRs are seen as a particularly promising solution because they can be designed to provide an equivalent service life through use of less material. The combination of the aggregate and geogrid materials creates an improved or mechanically stabilized layer (MSL) with a significantly increased resilient modulus. The objective of this study was to use existing testing protocol to determine and to evaluate material design parameters for an unbound and a geogrid MSL. To determine the effects of an MSL, a test combination that included AASHTO T307 and NCHRP 598 was conducted on both unbound and mechanically stabilized aggregate specimens.
Stabilization Effectiveness of Treatment with T-Shaped Deep-Mixing Column for Low-Volume Roads
Authors: Cai Guojun , Liu Songyu , Tong Liyuan
Published: July 2011

Deep-soil mixing using column elements is a widely used technology for improving soft soil properties for low-volume roads in China. The deep-mixing method has some limitations, because a high-treatment area over the entire column length makes this method expensive and impractical. On the basis of a stabilization mechanism and factors that affect column construction quality, a T-shaped bidirectional soil–cement deep-mixing column has been successfully developed and proved to be effective and economical. As part of quality control of field improvement of these columns, seismic piezocone penetration tests (SCPTUs) were used. The tests can provide near-continuous measurements of tip resistance, sleeve friction, and pore pressure induced during the penetration. This paper discusses field SCPTUs that were performed in the untreated soils and the interpile soils between the T-shaped bidirectional soil–cement deep-mixing columns at the Huzhou lacustrine clay site in China. Soil properties estimated from the SCPTU data both before and after improvement methods were compared to assess the effectiveness of soil improvement. These results indicate that the use of SCPTUs will improve understanding of the changes in soil behavior achieved by this novel deep-soil mixing method for low-volume roads.
Combined Lime–Cement Stabilization for Longer Life of Low-Volume Roads
Authors: Sirivitmaitrie Chakkrit , Puppala Anand J. , Saride Sireesh , Hoyos Laureano
Published: July 2011

Low-volume roads are an important part of the world's transportation infrastructure and a direct cause of the socioeconomic development of small city and rural communities. Construction, maintenance, and rehabilitation of these roads are major tasks and require a major part of the public works budget. Better design and construction methods can prolong pavement service life and result in lower maintenance and rehabilitation costs. This paper presents a research study done for the city of Arlington in north Texas to stabilize road subsoils with a combined lime and cement stabilizer, which in turn is expected to enhance service life of the roads. Both laboratory tests on stabilized soil mixtures and field performance data are analyzed and presented.
Performance of Full-Scale Test Section of Low-Volume Road with Reinforcing Base Layer of Soil–Lime
Authors: Behak Leonardo
Published: July 2011

The roads of the rice region of Merin Lake in Uruguay are subjected to low annual average traffic. However, the average daily traffic is approximately 100 trucks during harvest time. The local soils, characterized as clayey silts, are unsuitable for such traffic demands and are generally replaced or reinforced by materials found more than 70 km away, with high transportation costs. An investigation of the performance of a full-scale test section of pavement with a base layer of local silty clay soil stabilized with lime was conducted. The design of the test section consisted of soil selection, determination of lime content for stabilization, compaction, and California bearing ratio laboratory tests. Two test sections, each 50 m, were built, with a base layer of selected soil mixed with 3% lime in one section and with 5% lime in the other. After the rice harvest, the performance of the test sections was evaluated by visual observation of the base layer and deflection measures with a Benkelman beam. Despite some construction difficulties, the deflection average values changed from 244 × 10 2 cm immediately after the section was built to 77 × 10 2 cm 4 months later. The use of soil–lime material for base layers of low-volume roads is a technical and economical alternative that provides a significant improvement of the rural road network with socioeconomic benefits.
Toward Establishment of Industry Associations to Represent Nontraditional Road Stabilizer Suppliers
Authors: Jones David
Published: July 2011

Millions of miles of unsealed roads around the world are managed by a variety of agencies and owners. Unacceptable levels of dust, poor riding quality, impassability in wet weather, and unsustainable gravel replacement practices are experienced on much of this global unsealed road network, and although it is generally acknowledged that these roads are fundamental to the economies of almost every country, many of the management practices for these roads leave much to be desired, with programs for dust control, chemical stabilization, low-cost upgrading, and the like largely overlooked. Although considerable experimentation on a variety of chemical additives has been carried out since the early 1900s, little wide-scale implementation has taken place. There are many reasons for this, including the absence of national authorities, a fragmented and sometimes dishonest industry, poor-quality research, and a lack of funding for programs among agencies and owners operating unsealed roads. The formation of industry associations that represent additive manufacturers and suppliers is suggested as a means to overcoming some of these barriers to implementation. The potential roles of such associations include, but are not limited to, that of provision of a formalized platform to organize and lobby for wider use of chemical stabilizers in management of unsealed roads, establishment of criteria for additive characterization–categorization, development of testing protocols, formulation of specifications, establishment of fit-for-purpose certification systems, enforcement of a code of conduct for its members, development of guidelines for marketing of additives, and provision of outreach.
Various Additives Used as Alternative to Conventional Road Construction
Authors: Uys Robbie , Truter Llewellyn , Van Zyl Gerrie
Published: July 2011

The Western Cape Provincial Administration in South Africa initiated an experimental study to investigate the use of various additives as an alternative to conventional regraveling construction of a gravel road. The in situ material was reworked and stabilized with nontraditional stabilizers. A control section, together with a section stabilized with a traditional stabilizer, was used to compare the performance of the various sections over time. Three sections were also sealed with a bituminous surface and monitored over time. Monitoring of the sections was done either up to the point at which the road surface broke up or for 2½ years. The performance of the different monitoring sections, representing different types of additives and varying-quality (marginal) in situ material—but under the same conditions of climate, traffic volume, and construction technique—were monitored and compared over time. Four main areas of performance were monitored: during construction, in the laboratory, over time, and in economic terms. This paper provides background on the different additives used, a summary of the experimental design, and a brief discussion of the various products. It emphasizes construction and performance monitoring over time and analysis of the results. Apart from interesting observations, conclusions are made by looking not only at performance but also by taking vehicle operating and life-cycle costs into consideration.
Project Selection Guidelines for Road Rehabilitation through Full-Depth Reclamation with Foamed Asphalt
Authors: Jones David , Fu Pengcheng
Published: July 2011

Full-depth reclamation–recycling—or deep in situ recycling—of damaged pavement with foamed asphalt and an active filler (e.g., portland cement or lime) to provide a stabilized base for a new hot-mix asphalt or chip-sealed wearing course, is a pavement rehabilitation–upgrading strategy of increasing interest worldwide. However, the process is not a fix-all solution that can be used in every instance to rehabilitate failed or close-to-failed pavements, and a thorough project investigation needs to be undertaken to identify candidate projects as well as problems that need to be corrected before rehabilitation–upgrading can be considered. This paper provides guidelines for undertaking such an investigation and is applicable to projects with both thin (multiple chip seals) and thick (multiple lifts of thin asphalt concrete) surfacings.
Performance of Recycled Asphalt Pavement in Gravel Roads
Authors: Koch Scott , Ksaibati Khaled , Huntington George
Published: July 2011

Because more recycled asphalt pavement (RAP) has become available to use in roadways, the Wyoming Technology Transfer–Local Technical Assistance Program Center and two Wyoming counties saw a need to investigate the use of RAP in gravel roads. The Wyoming Department of Transportation along with the Mountain Plains Consortium funded this study. The investigation explored the use of RAP as a means of dust suppression while considering road serviceability. Test sections were constructed in the two counties and were monitored for dust loss by means of the Colorado State University dustometer. Surface distress evaluations of the test sections were performed following a technique developed by the U.S. Army Corps of Engineers in Unsurfaced Road Maintenance Management (Special Report 92–26). The data collected were statistically summarized and then analyzed. The performance of RAP sections was compared with that of gravel control sections. This comparison allowed fundamental conclusions and recommendations to be made for RAP and its ability to abate dust. It was found that RAP-incorporated gravel roads can reduce dust loss without adversely affecting the road's serviceability. Other counties and agencies can expand on this research to add to the toolbox for dust control on gravel roads.
Repair of Storm-Damaged Slopes, Lower Mount Wilson Road, Los Angeles County, California
Authors: Keaton Jeffrey R. , Perry David L. , Kim Philip W.
Published: July 2011

The lower 4.2 km (2.6 mi) of Mount Wilson Road provides exclusive vehicle access to Los Angeles County Fire Department facilities at Henninger Flats in the San Gabriel Mountains north of Pasadena, California. Severe storms in January 2005 rendered the road impassable by debris sloughing from above and soil sliding below the roadway; a fiber-optical communication line buried in the road was not broken. Slope damage ranged in scale from localized shallow sloughing to major slope movements up to about 90 m (300 ft) wide and 120 m (400 ft) in vertical height. Repair measures considered to restore vehicle access were very expensive and likely to be damaged by future slope movements. Henninger Flats is the head of a megaslide in Precambrian metamorphic rocks that encompasses more than 2.8 km2 (1 mi2). Typical safety factors required for Los Angeles County projects could not be attained with reasonable cost; therefore, repairable deformation that is passable by field vehicles was selected as the repair criterion. The two worst locations adjacent to Pasadena were repaired in 2009 with gabion baskets and welded-wire reinforced soil systems. Preliminary designs were developed for material quantities; field engineering was used to manage specific problems encountered during construction. Once the largest slides near the bottom of the road were repaired, fire department maintenance crews used the county's fire-fighting equipment to clear the road, providing vehicle access to Henninger Flats. Slide debris stability improved during the 4-year period between storm damage and road repair, contributing to the success of the project.
Laboratory Evaluation of Hot-Mix Asphalt Containing Petroleum-Contaminated Soil as a Surface Mix for Low-Volume Roads
Authors: Hassan Hossam F. , Al-Rawas Amer Ali
Published: July 2011

Petroleum-contaminated soil (PCS) is typically a mixture of sand, silt, clay, and petroleum products. In Oman, Petroleum Development Oman generates approximately 53,000 tons/year of PCS. The amount raises a significant disposal problem. Results are presented on the use of PCS in hot asphalt mixes as potential surface mixes for low-volume roads. The mixes were designed with the Marshall mix design method. The dynamic modulus |E*| test, as a primary material property input in the Mechanistic-Empirical Pavement Design Guide (MEPDG), was conducted at different frequencies (0.1 to 16 Hz) and temperatures (25°C to 60°C). |E*| master curves and shift factors were developed for the control and PCS mixes and compared with Witczak's predictive models. Environmental assessment of PCS indicated that it posed no threat to the environment. The mix design results indicated that mixes containing up to 15% PCS met the specification limits set for high-volume surface mixes except for voids in mineral aggregate (VMA), which was lower than the specification limits. Mixes containing up to 30% and 40% PCS met the low-volume surface or base mix specifications set by the Asphalt Institute with the exception of air voids or VMA for some mixes. The |E*| and indirect tensile strength results were consistent with Marshall stability. Witczak's predictive model for |E*| agreed well with the laboratory-fitted results for 0% and 5% PCS mix up to a 10-Hz frequency. This paper contributes to MEPDG implementation by developing the necessary parameters and optimizing the mix design of the PCS mixes.
Performance Evaluation and Environmental Impact Assessment of Asphalt-Treated Mixtures Used in Low-Volume Roads
Authors: Mohammad Louay N. , Nazzal Munir D.
Published: July 2011

The performance of asphalt-treated mixtures used in low-volume roads was evaluated, and their environmental benefits were assessed. Laboratory tests, including permeability, modified Lottman, Hamburg-type loaded wheel tracking, flow number, semicircular bend, dissipated creep strain energy, and dynamic modulus tests, were performed to examine the physical and mechanical properties of the asphalt-treated mixtures. Mechanistic–Empirical Pavement Design Guide (MEPDG) software was used to compare the performance of low-volume pavement sections with asphalt-treated mixtures to that of a conventional hot-mix asphalt (HMA) mixture. Life-cycle assessment was also conducted to quantify the environmental impacts of using asphalt-treated mixtures in lieu of conventional HMA mixtures in the construction of low-volume roads. Test results demonstrated that asphalt-treated mixtures containing limestone and reclaimed asphalt pavement exhibited similar properties to those of well-performing conventional HMA mixtures. MEPDG analysis showed that pavement sections with asphalt-treated mixtures exhibited similar performance to those with conventional low-volume HMA mixtures. Life-cycle assessment indicated that using asphalt-treated mixtures in low-volume roads could result in reductions of up to 29% in carbon dioxide emissions, 29% in energy consumption, 39% in water consumption, and 42% in hazardous waste generation.
Late-Season Paving of a Low-Volume Road with Warm-Mix Asphalt
Authors: Saboundjian Steve , Liu Juanyu , Li Peng , Brunette Bruce
Published: July 2011

This paper documents late-season paving of a gravel, low-volume roadway on Mitkof Island in the Tongass National Forest in southeast Alaska. The project was Alaska's first experience with warm-mix asphalt (WMA) technology. In 2008, Sasobit (1.5% by weight of asphalt) was added to a PG 58-28 polymer-modified asphalt at the producer's plant, barge-shipped 800 mi to the project site, and used for paving the two-lane, 24-ft-wide roadway located 20 mi south of Petersburg, Alaska. About 23,000 tons of WMA were placed with no major problems. Compaction of the WMA was achieved at about 50°F lower than the conventional hot-mix asphalt (HMA) used in an adjacent project. Reduced fumes were observed compared with the HMA. The contractor reported fuel savings and ease of WMA compaction. One roller was used to compact the WMA and achieve mix density. Postconstruction smoothness and rut depth measurements revealed trends similar to those at the adjacent conventional HMA project. The project will be monitored for 3 years to assess near-term performance. Loose-mix samples collected from the WMA project and the adjacent HMA project were used to produce laboratory-compacted specimens for performance testing. Modulus and rutting test results showed that WMA was stiffer and more rutting-resistant than the conventional mix. No adverse low-temperature cracking issues were detected. WMA's moisture susceptibility was similar to that of the conventional mix. With this successful WMA experience, it is expected that WMA will be used in future Alaskan paving projects, especially for late-season paving and for remote, low-volume roadways.
Aeolian Sands as Material to Construct Low-Volume Roads
Authors: Paige-Green P. , Pinard M. I. , Mgangira M.
Published: July 2011

Aeolian sands are widespread in many semiarid to arid areas of the world and often provide the only economic source of construction materials for low-volume roads. Experience in southern Africa over a number of decades has shown that provided aeolian sand materials are correctly selected and constructed, they can make effective subgrade, subbase, and base layers for low-volume roads. Research into their use has shown that the use of standard geological (sedimentological) techniques for classification allows the differentiation of sands that will perform well or badly as road base and subbase materials. The technique discussed uses the phi classification system, which defines the sands by their mean particle size and the standard deviation about this mean. Simple techniques for assessing the suitability of these materials for use and innovative construction methods for their use are described. The results obtained during monitoring of various roads indicate the benefits of well-compacted sand subgrades.
Evaluation of Gravel Loss Deterioration Models
Authors: Uys Robbie
Published: July 2011

Efforts have been made by the Western Cape Provincial Administration in South Africa to improve all aspects of gravel road construction and maintenance. This thrust has resulted in better performance over time, as had been predicted by gravel loss deterioration models. Various internationally recognized gravel loss deterioration models were evaluated, and their predictions of gravel loss were compared with actual measurements of gravel loss. Through an extensive selection and design process and by incorporating various material property, traffic volume, environmental, and geometric parameters, 20 monitoring sections were selected for comparison. This monitoring was done for more than 5 years, starting in 2003. This paper summarizes the various available gravel loss deterioration models, provides a sensitivity analysis, discusses the improved processes, and gives a brief summary of the experimental design that was followed. The experimental monitoring and the analysis of the measured and predicted annual gravel loss as well as the comparison of the measured with the predicted gravel loss are also discussed. The impact of the sensitivity analysis and the comparison between the actual measurements and the predicted gravel loss as determined from the deterioration models are highlighted. Conclusions and suggested adjustments to the models or to the monitoring procedures are made. The two models that gave the best comparisons to the measured results and that would benefit the most by the suggested adjustments are the Technical Recommendations for Highways Manual 20 model and the World Bank Highway Development and Management model.
Development and Implementation of Ultrathin Concrete Road Technology for Suburban Streets in South Africa
Authors: Louw M. R. , Rust F. C. , Bergh A. O. , McKay A. H.
Published: July 2011

There is a significant need in South Africa for the upgrading of suburban streets with a solution that performs well, is cost-effective, and requires minimal maintenance. There is also a need for job creation in road construction, using local labor when possible. The ultrathin reinforced concrete pavement (UTRCP) technology, one such solution, was developed by the Council for Scientific and Industrial Research in South Africa and has been implemented in a number of projects. The technology was developed for suburban streets and roads carrying fewer than 2,500 vehicles/day and is constructed with labor using light plant. UTRCP consists of a lightly reinforced, 50-mm-thick, 30-MPa concrete layer that is generally constructed on shaped and compacted in situ material; modification may be required if the in situ material has a high plasticity index. Experimental work was conducted by testing trial sections of UTRCP supported by various subbase layers. This included static testing, rolling wheel load testing with a heavy vehicle simulator, and evaluation of the performance of trial sections under normal traffic. The results of the experimental work and the subsequent proposed structural designs used in implementation projects are described. The technology has been implemented in various projects in suburban townships in South Africa in the Gauteng Province. The practical lessons learned from these projects are described. Lastly, criteria for the subbase design of pavement structures containing the UTRCP layer are proposed, and further work is suggested.
Use of Recycled Materials to Build Paver Blocks for Low-Volume Roads in Developing Countries
Authors: Serrano-Guzman Maria Fernanda , Perez-Ruiz Diego Dario
Published: July 2011

The civil engineering profession is challenged with rebuilding and maintaining a decaying infrastructure and addressing the ever-increasing problem of solid waste. These two issues are interrelated because of the reconstruction or rehabilitation of roads and highway pavements and because building generates an enormous amount of solid waste, which puts tremendous pressure on depleting landfill space. All these factors imply that recycling the waste aggregate from demolished pavements and buildings can have significant benefit for the environment and at the same time be an attractive option for highway construction, as a result of the savings in material acquisition and disposal costs. With that in mind, this research was undertaken to develop and characterize an alternative road surface material consisting of recycled crushed concrete aggregate, natural aggregates, and portland cement to achieve desirable mechanical characteristics. The study is aimed toward assessing the performance of the composite material that allows the saving of material costs by using recycled aggregate instead of expensive and often scarce virgin aggregates. The resulting material will perform at least as well as (and perhaps better than) the normally used composite material built with natural aggregates.
Improvement Recommendations for Unsealed Gravel Roads
Authors: Huntington George , Ksaibati Khaled
Published: July 2011

A method was developed to recommend improvements for unsealed earth and gravel roads that are not up to the standard expected for their functional class. As part of a pilot asset management program carried out by the Wyoming Technology Transfer Center, roads were rated for several distresses, including corrugations–washboards, rutting, potholes, loose aggregate, drainage, dust, and overall condition by using a visual survey method. These ratings were used to calculate a surfacing serviceability index (SSI) for each road section. This SSI was compared with the minimum acceptable SSI for the section's functional class. When the section's SSI was below this threshold value, improvement tasks were selected from a decision matrix, and the most expensive task was recommended to address the section's inadequate surface condition. This process allows an agency to present its elected officials with a list of roads in their network that need improvement, along with an estimate of the cost of these improvements. The method presented in this paper can be used by agencies with extensive unsealed road networks if they perform a visual survey rating various distresses and they develop a decision matrix based on these distresses to establish appropriate improvements to substandard roads.
Implementation Guide for the Management of Unsealed Gravel Roads
Authors: Huntington George , Ksaibati Khaled
Published: July 2011

To address the current lack of a gravel roads management system (GRMS) appropriate for the rural agencies of the Intermountain West and the Great Plains, the Wyoming Technology Transfer Center (T2/LTAP) consulted with a volunteer group of experts and practitioners in the fields of unsealed earth and gravel roads and roadway management to put together a set of recommendations and guidelines for managing unsealed roads. This paper describes and summarizes the gravel roads management methodology developed by T2/LTAP under the guidance of this group. Steps in implementing a GRMS are described, beginning with an assessment stage in which an agency evaluates its current unsealed roads information management and the resources available to improve it. Next, three elements of a GRMS are described: data management, inventory, and data collection. Eight maintenance tasks for unsealed roads are described: blading, reshaping, regraveling, dust control, stabilization, isolated repairs, major work, and drainage maintenance. Primary outputs of a GRMS are described, including cyclic maintenance scheduling, triggered maintenance scheduling, and network-level outputs, including network-level monitoring, financial tables, and road tables and maps. Safety and drainage assessments are described briefly. Recommendations are made for putting these procedures into practice.
Network-Level Pavement Management
Authors: Mladenovic Goran , Cirilovic Jelena , Queiroz Cesar
Published: July 2011

This paper presents the application of the World Bank's Road Network Evaluation Tools (RONET) model to strategic network-level analysis of the Serbian state low-volume road (LVR) network. This network condition deteriorated considerably during the 1990s as a result of the under-financing of its operations and maintenance. In recent years, financing for the road sector has gradually increased and focuses on the most hazardous and highly trafficked parts of the network. However, the overall budget allocated to the sector remains inadequate to maintain the entire state road network in stable condition. The goals of the presented study are to obtain the optimum maintenance and rehabilitation (M&R) strategy and related budget, estimate the impact of different funding levels on future quality, and estimate the economic consequences of budget constraints for the M&R of the LVR network. Application of the RONET model to the prevailing conditions on the Serbian LVR network led to an optimal M&R strategy with a good balance between rehabilitation and periodic and recurrent maintenance. Implementation of the optimal M&R strategy would cause major improvement compared with the current condition of the LVR network. Implementation of higher M&R standards would lead to substantially higher road agency costs and, consequently, lower net benefits, whereas the implementation of lower M&R standards would lead to considerably worse network condition for approximately the same or slightly lower agency costs. This situation means that even minor budget constraints would result in considerably worse network condition and much higher total road transport costs.
Performance Evaluation of Whitetopping and Ultrathin Whitetopping Pavements
Authors: Li Xiaojun , Wen Haifang
Published: July 2011

Whitetopping overlay is a relatively new rehabilitation technology as an alternative to hot-mix asphalt (HMA) overlay. It is defined as a portland cement concrete (PCC) overlay on the existing deteriorated HMA pavement to improve the structural and functional capability. When the PCC overlay thickness is less than or equal to 10.16 cm (4 in.), it is referred to as ultrathin whitetopping (UTW). Otherwise it is referred to as normal whitetopping (WT). The objective of this research is to evaluate the performance of in-service whitetopping pavements as a rehabilitation technology by means of a pavement distress survey and falling weight deflectometer test. The performance of whitetopping pavements was characterized by the pavement condition index and pavement distress index. Statistical analysis of the performance was conducted in regard to major factors. Slab thickness, slab size, and pavement age were found to have a significant effect on the performance. The critical distance method and the MODCOMP6 program were applied in this study to backcalculate the layer properties of UTW and WT, respectively. KENSLAB was used to determine pavement response for fatigue analysis.
New Cembranolides from the Dongsha Atoll Soft Coral Lobophytum durum
Authors: Cheng Shi-Yie , Chen Pei-Wen , Chen Hwa-Pyng , Wang Shang-Kwei , Duh Chang-Yih
Published: July 2011

Chemical investigations of the Dongsha Atoll soft coral Lobophytum durum resulted in the isolation of five new cembranolides, durumolides M–Q (1–5). The structures of compounds 1–5 were characterized by the interpretation of extensive spectroscopic analysis. Compound 4 exhibited cytotoxicity against P-388 (mouse lymphocytic leukemia) cell line with an ED50 of 3.8 μg/mL. Moreover, compound 5 showed significant antiviral activity against human cytomegalovirus with an IC50 of 5.2 μg/mL.
Novel Library of Selenocompounds as Kinase Modulators
Authors: Plano Daniel , Ibáñez Elena , Calvo Alfonso , Palop Juan Antonio , Sanmartín Carmen
Published: July 2011

Although the causes of cancer lie in mutations or epigenic changes at the genetic level, their molecular manifestation is the dysfunction of biochemical pathways at the protein level. The 518 protein kinases encoded by the human genome play a central role in various diseases, a fact that has encouraged extensive investigations on their biological function and three dimensional structures. Selenium (Se) is an important nutritional trace element involved in different physiological functions with antioxidative, antitumoral and chemopreventive properties. The mechanisms of action for selenocompounds as anticancer agents are not fully understood, but kinase modulation seems to be a possible pathway. Various organosulfur compounds have shown antitumoral and kinase inhibition effects but, in many cases, the replacement of sulfur by selenium improves the antitumoral effect of compounds. Although Se atom possesses a larger atomic volume and nucleophilic character than sulfur, Se can also formed interactions with aminoacids of the catalytic centers of proteins. So, we propose a novel chemical library that includes organoselenium compounds as kinase modulators. In this study thirteen selenocompounds have been evaluated at a concentration of 3 or 10 µM in a 24 kinase panel using a Caliper LabChip 3000 Drug Discover Platform. Several receptor (EGFR, IGFR1, FGFR1…) and non-receptor (Abl) kinases have been selected, as well as serine/threonine/lipid kinases (AurA, Akt, CDKs, MAPKs…) implicated in main cancer pathways: cell cycle regulation, signal transduction, angiogenesis regulation among them. The obtained results showed that two compounds presented inhibition values higher than 50% in at least four kinases and seven derivatives selectively inhibited one or two kinases. Furthermore, three compounds selectively activated IGF-1R kinase with values ranging from −98% to −211%. In conclusion, we propose that the replacement of sulfur by selenium seems to be a potential and useful strategy in the search of novel chemical compound libraries against cancer as kinase modulators.
Risk Assessment and Examination of Economic Aspects of Precision Weed Management
Authors: Takács-György Katalin , Takács István
Published: July 2011

The aim of this research is to investigate plant production sustainability, the economical requirements, risks, and identify threshold levels to switching on, or off precision weed management techniques in Hungarian growing and sales conditions; taking into consideration that the implementation of precision technology can be justified also by its role in the reduction of environmental load, which would create a harmony between individual usefulness and social utility. A simulation model has been developed to investigate the return of extra investments, along with the risk of this return in relation to the soil type, weed coverage, and the sales price.
Action Duality: A Constructive Principle for Quantum Foundations
Authors: Wharton Ken B. , Miller David J. , Price Huw
Published: July 2011

An analysis of the path integral approach to quantum theory motivates the hypothesis that two experiments with the same classical action should have dual ontological descriptions. If correct, this hypothesis would not only constrain realistic interpretations of quantum theory, but would also act as a constructive principle, allowing any realistic model of one experiment to generate a corresponding model for its action-dual. Two pairs of action-dual experiments are presented, including one experiment that violates the Bell inequality and yet is action-dual to a single particle. The implications generally support retrodictive and retrocausal interpretations.
Retrospective study of 476 tibial plateau levelling osteotomy procedures
Authors: Dupuis J. , Planté J. , Moreau M. , Gatineau M.
Published: July 2011

Objective: To determine the rate of subsequent ‘pivot shift’, meniscal tear and risk factors associated with complications of tibial plateau levelling osteotomy (TPLO) and to assess clinical and owner perception outcome.

Study design: Retrospective study.

Sample population: Three hundred and forty-eight dogs that had undergone TPLO surgical procedures (n = 476 stifles).

Methods: Medical records were reviewed for the retrieval of information on breed, sex, age, body weight, clinical history, radiograph findings, pre- and postoperative tibial plateau angle, limb alignment, unilateral versus bilateral disease, condition of cranial cruciate ligament (CCL) and menisci, implant material, healing time and complications. Clinical and owner-assessed questionnaire outcomes were also recorded.

Results: Forty-six (9.7%) postoperative complications were reported. Twenty (4.2%) were classified as major complications requiring an additional surgical intervention, and 26 (5.5%) as minor complications. No risk factors associated with postoperative complications were identified. Ten (2.1%) subsequent meniscal injuries in the stifles with normal unaltered menisci at time of TPLO were reported with a median postoperative time of 9.5 months. Signs of postoperative ‘pivot shift’ were reported in 15 (3.1%) stifles. All stifles with a ‘pivot shift’ had a complete CCL rupture or a debrided partial CCL rupture a medial menisectomy was identified as a risk factor for a ‘pivot shift’ (p = 0.02). Dogs with intact medial meniscus had a significantly higher activity level (p <0.0001) and a shorter time to peak function (p = 0.02) than dogs that underwent menisectomy according to an owner questionnaire.

Conclusions: Dogs with TPLO and intact meniscus seemed to have a better and faster recovery than dogs with TPLO and menisectomy based on owner questionnaires. ‘Pivot shift’ was infrequent after TPLO surgery. All dogs with a ‘pivot shift’ had a complete CCL rupture or a debrided partial CCL rupture and menisectomy was identified as a risk factor for its occurrence.

Clinical relevance: Considering the relatively low rate of subsequent meniscal injury after TPLO, systematic medial meniscal release with TPLO may be unnecessary. The ‘pivot shift’ deserved further investigation to completely understand its mechanism, to identify its anatomic components and potential consequences on the stifle joint.
A cryogenic clamping technique that facilitates ultimate tensile strength determinations in tendons and ligaments
Authors: Bowser J. E. , Elder S. H. , Rashmir-Raven A. M. , Swiderski C. E.
Published: July 2011

Objective: To describe the use of a cryogenic clamp of novel design for tensile strength testing of tendinous and ligamentous tissues with inherently high tensile strength.

Methods: Inexpensive, easily machined steel clamps were manufactured to facilitate rapid insertion into a standard wedge-screw grip apparatus installed on a testing system with a control system attached. The deep digital flex-or tendon (DDFT) of six horses was trimmed to a uniform dumbbell shape and secured in clamps using partial submersion in liquid nitrogen for approximately 45 seconds and immediately tested. Approximate time between removal from liquid nitrogen and failure of tendon was four minutes.

Results: Failure was achieved in all tendons tested in a region approximating a midpoint between the clamps. Ultimate failure loads of up to 6745 N were achieved without slippage of the tissue from the grips. The ultimate tensile strength of the normal equine DDFT determined in this study was 111.82 ± 11.53 N/mm2, and the stress versus grip-to-grip elongation plots for our equine DDFT were representative of a standard non-linear elastic curve obtained in similar studies.

Clinical significance: We present a low cost device for quantifying physical properties of specimens with high connective tissue concentrations and inherent high tensile strength. Results of this study indicate that this device provides a practical alternative to other more costly methods of adequately securing larger tendons and ligaments for tensile strength testing.
Osteogenic differentiation of equine cord blood multipotent mesenchymal stromal cells within coralline hydroxyapatite scaffolds in vitro
Authors: Figueroa R. J. , Koch T. G. , Betts D. H.
Published: July 2011

Objective: To investigate the osteogenic differentiation potential of equine umbilical cord blood-derived multipotent mesenchymal stromal cells (CB-MSC) within coralline hydro-xyapatite scaffolds cultured in osteogenic induction culture medium.

Methods: Scaffolds seeded with equine CBMSC were cultured in cell expansion culture medium (control) or osteogenic induction medium (treatment). Cell viability and distribution were confirmed by the MTT cell viability assay and DAPI nuclear fluorescence staining, respectively. Osteogenic differentiation was evaluated after 10 days using reverse transcription polymerase chain reaction, alkaline phosphatase activity, and secreted osteocalcin concentration. Cell morphology and matrix deposition were assessed by scanning electron microscopy (SEM) after 14 days in culture.

Results: Cells showed viability and adequate distribution within the scaffold. Successful osteogenic differentiation within the scaffolds was demonstrated by the increased expression of osteogenic markers such as Runx2, osteopontin, osteonectin, collagen IA increased levels of alkaline phosphatase activity increased osteocalcin protein secretion and bone-like matrix presence in the scaffold pores upon SEM evaluation.

Clinical significance: These results demonstrate that equine CB-MSC maintain viability and exhibit osteogenic potential in coralline hydroxyapatite scaffolds when induced in vitro. Equine CB-MSC scaffold constructs deserve further investigation for their potential role as biologically active fillers to enhance bone-gap repair in the horse.
Arthroscopic surgery of the middle carpal joint in trotting Standard-breds: Findings and outcome
Authors: Ronéus B. , Ljungvall K.
Published: July 2011

Objectives: To describe the injuries in the middle carpal joint of trotting Standardbred racehorses in relation to future racing and to review the use of synovectomy in clinical cases.

Methods: Review of medical records and racing statistics of clinical cases.

Results: Sixty-six percent of horses undergoing arthroscopic surgery of the middle carpal joints returned to racing, but there were only weak associations between future racing success and findings at surgery. Lesions in the middle carpal joint were similar to what have previously been described, but there were no recorded injuries to the intermediate carpal bone in the horses in this sample population.

Clinical relevance: Making an accurate prognosis for return to racing based on the findings in the middle carpal joint at the time of surgery appears to be difficult.
Le conditionnement lexical de l'élision des liquides en contexte post-consonantique final
Authors: Pustka Elissa
Published: July 2011

L’article expose, s’appuyant sur une base empirique large (33 heures de corpus PFC), à quel point le comportement des liquides post-consonantiques finales est conditionné par le lexique, et cela de manière comparable dans des variétés régionales très différentes (français méridional, antillais et parisien). Le taux d’élision de la liquide est, en effet, minimal dans le cas de entre , autour de la moyenne pour être , notre et autre(s) , et maximal pour par exemple , peut-être et par contre . Cela s’explique non par la fréquence de ces mots dans la parole, comme des études antérieures le suggèrent, mais par la fréquence d’apparition du mot en question dans les différents contextes prosodiques, qui, eux, sont liés à des facteurs morphosyntaxiques : plus un mot se trouve dans un contexte de forte cohésion morphosyntaxique et prosodique, plus la liquide sera maintenue – et l’inverse.
La recherche de régularités distributionnelles pour la catégorisation du schwa en français
Authors: Andreassen Helene N.
Published: July 2011

Malgré un accord prévalent dans la littérature sur l’autonomie du schwa, nous envisagerons ici, en fonction de trois types de données, une analyse plus minimaliste avec le schwa comme variante du /œ/. Des données tirées de jugements montrent des tendances distributionnelles avant tout au niveau de la structure morphologique, renforcées par des données de production. Cependant, suite à l’examen du langage adressé à l’enfant – avec un taux d’absence du schwa légèrement différent – nous proposerons que la distribution à laquelle est exposé l’enfant n’est pas identique à celle de la langue cible adulte, ce qui pourrait avoir des implications pour la catégorisation du schwa.