Manufactured fine aggregates are a product created when rocks are crushed using a mechanical crusher. With the depletion of sources of natural sands, the usage of manufactured fine aggregates has increased. Manufactured fine aggregates have properties that differ from natural sands; for this reason, the plastic and hardened properties of concrete produced using manufactured fine aggregates differ from the properties of concrete made with natural sands. The main concrete properties affected by the usage of manufactured fine aggregates are skid resistance, workability, and finishability. The aim of this research project was to investigate how manufactured fine aggregates could be used in concrete pavements without causing workability or skid related issues. To improve the workability of concrete made with manufactured fine aggregates, the use of the optimized mixture proportioning method developed by the International Center for Aggregate Research (ICAR) was investigated. Results obtained from this testing were used to make recommendations on how the ICAR method for pavement concrete could be improved The goal of this research was to also develop laboratory tests that could reasonably predict skid performance of concrete pavements made with different types of sand. For this purpose concrete slabs made with different sands were evaluated for friction and texture using a circular texture meter (CTM), a dynamic friction tester (DFT), and a polisher. To ensure that the values obtained at the laboratory related to field performance, test sections constructed with 100% limestone sand and blended sands were evaluated. Laboratory and field test results for skid were used to identify aggregate tests that best correlates with concrete performance. Results show that the micro-Deval test for fine aggregates could be used to predict the polish resistance of concrete laboratory specimen. Results from field testing has shown that if limestone fine aggregates are not blended with siliceous sands, PCC pavements made with limestone sands on truck lanes could experience a large drop in skid resistance within a year of service. Results obtained from laboratory testing showed that blending a small quantity of siliceous sand with limestone sands considerably increased the skid resistance of concrete specimens. / text

Disertacijos tikslas – pateikti moksliškai pagrįstą komponentų sąveikos dinamikos modelį ir jos rezultatus, leidžiančius projektuoti bei gaminti kokybiškus karštai maišytus asfalto mišinius su Lietuvos kelių dangoms naudoto asfalto granulėmis. Disertacijoje sprendžiami šie pagrindiniai uždaviniai: − Atlikti paiešką, surinkti, dalykiškai susisteminti ir išanalizuoti mokslo darbus, kuriuose tiriama: asfaltinės dangos irties veiksniai ir jų įtaka naudotam asfaltui; senų ir naujų medžiagų sąveika; regeneruoto asfalto mišinio savybės; regeneravimo proceso technologijos. − Sumodeliuoti naudoto asfalto homogeniškumą lemiančius veiksnius. − Sumodeliuoti dviejų rūšių sumaišyto bitumo ar kitos atnaujinančiosios medžiagos teorinę klampą ir seno bei naujo bitumų maišymosi dėl difuzijos dvisluoksnėje plėvelėje dinamiką. − Pateikti susistemintus asfaltinės dangos regeneravimo principus. − Surinkti duomenis apie Lietuvoje išgaunamo naudoto asfalto kiekių dinamiką bėgant metams. − Ištyrinėti Lietuvos keliuose ir miesto gatvėse frezuoto bei išlaužto ir sutrupinto naudoto asfalto granulių komponentines sudėtis ir savybes. − Nustatyti pridedamo atnaujinančio bitumo rūšies ir procentinio kiekio įtaką regeneruoto karštai maišyto asfalto (KMA) mišinio fiziniams ir mechaniniams Maršalo rodikliams, taip pat regeneruoto suminio bitumo savybėms. − Nustatyti su skirtingu kiekiu naudoto asfalto granulėmis regeneruoto KMA mišinio atsparumą vėžių susidarymui. − Pateikti naujus deterministinio ir... [toliau žr. visą tekstą] / The purpose of the dissertation is to provide a science-based model of the interaction dynamics among the components and the results of this interaction, which shall help to design and to produce high quality hot-mix asphalt mixtures with granules of recycled asphalt pavement of Lithuanian roads. The main objectives of the dissertation: – To conduct the research, to collect, systemized and analyzed scientific works discussing the factors of asphalt pavement distresses and their influence on the performance of recycled asphalt, the interaction between old and virgin materials, the properties of recycled asphalt pavement mixture, and the recycling process technologies. – To model the factors determining the homogeneity of recycled asphalt pavement. – To model the theoretical viscosity for two types of blended bitumen or for another rejuvenator, and the dynamics of old and virgin bitumen mixing due to the diffusion process occurring in the two-layer film. – To provide systemized principles of asphalt pavement recycling. – To collect the data to show the dynamics of the amount of recycled asphalt pavement used in Lithuanian over the years. – To study the component composition and properties of granules of milled, broken and crushed recycled asphalt taken from Lithuanian roads and city streets. – To determine the influence of rejuvenating bitumen type and its percentage amount on physical and mechanical Marshall Parameters of recycled hot-mix asphalt mixture and on the properties... [to full text]

This thesis investigates and documents fundamental studies of highway materials (asphalt engineering properties) especially on different modified asphalt binders and mixtures in order to understand failure mechanisms at low temperature and superior performance of such asphalt binders with the aim of preventing premature cracking on Ontario highways. In addition, seven asphalt binders of different compositions were used as a template for study and this research work is tailored towards Superpave® performance-based specification testing with the aim of improving asphalt pavement performance under various conditions and consequently reducing premature cracking in order to achieve long lasting highways. Based on the actual applied pattern of Superpave® specification criteria, the mechanical responses of the binders are analyzed by extended bending beam rheometer (eBBR), tensile stress ductilometer (Petrotest DDA3®), compact tension test (Instron AsphaltPro®), double-edge-notched tension and single-edge-notched tension (MTS 810 universal testing machine) protocols. The objective of this study entails establishing and developing of a proper procedure for the testing of binders with the aim of ranking (grading) the performance after validation of laboratory and field experiments. Analysis of the results appears to show that the premature distress on the Highway 417 trial sections can be attributed to reversible aging tendency (wax crystallization) at low temperatures coupled with low fatigue resistance of the binders. The results suggest that different polymer modifications had significant influence on the performance of asphalt mix as demonstrated from the results obtained from essential and plastic work of fracture using double-edge-notch-tension test (DENT). Crack tip opening displacement (CTOD) parameter consistently show the performing grading of asphalt binder while compact tension test protocol provides plane strain fracture toughness (K1c) which could be used to rank binders with respect to fracture resistance at low temperature. Hence, CTOD is a promising parameter which can be used to establish performance ranking of the binders. / Thesis (Master, Chemistry) -- Queen's University, 2008-05-26 09:54:23.308

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The purpose of the dissertation is to provide a science-based model of the interaction dynamics among the components and the results of this interaction, which shall help to design and to produce high quality hot-mix asphalt mixtures with granules of recycled asphalt pavement of Lithuanian roads. The main objectives of the dissertation: – To conduct the research, to collect, systemized and analyzed scientific works discussing the factors of asphalt pavement distresses and their influence on the performance of recycled asphalt, the interaction between old and virgin materials, the properties of recycled asphalt pavement mixture, and the recycling process technologies. – To model the factors determining the homogeneity of recycled asphalt pavement. – To model the theoretical viscosity for two types of blended bitumen or for another rejuvenator, and the dynamics of old and virgin bitumen mixing due to the diffusion process occurring in the two-layer film. – To provide systemized principles of asphalt pavement recycling. – To collect the data to show the dynamics of the amount of recycled asphalt pavement used in Lithuanian over the years. – To study the component composition and properties of granules of milled, broken and crushed recycled asphalt taken from Lithuanian roads and city streets. – To determine the influence of rejuvenating bitumen type and its percentage amount on physical and mechanical Marshall Parameters of recycled hot-mix asphalt mixture and on the properties... [to full text] / Disertacijos tikslas – pateikti moksliškai pagrįstą komponentų sąveikos dinamikos modelį ir jos rezultatus, leidžiančius projektuoti bei gaminti kokybiškus karštai maišytus asfalto mišinius su Lietuvos kelių dangoms naudoto asfalto granulėmis. Disertacijoje sprendžiami šie pagrindiniai uždaviniai: − Atlikti paiešką, surinkti, dalykiškai susisteminti ir išanalizuoti mokslo darbus, kuriuose tiriama: asfaltinės dangos irties veiksniai ir jų įtaka naudotam asfaltui; senų ir naujų medžiagų sąveika; regeneruoto asfalto mišinio savybės; regeneravimo proceso technologijos. − Sumodeliuoti naudoto asfalto homogeniškumą lemiančius veiksnius. − Sumodeliuoti dviejų rūšių sumaišyto bitumo ar kitos atnaujinančiosios medžiagos teorinę klampą ir seno bei naujo bitumų maišymosi dėl difuzijos dvisluoksnėje plėvelėje dinamiką. − Pateikti susistemintus asfaltinės dangos regeneravimo principus. − Surinkti duomenis apie Lietuvoje išgaunamo naudoto asfalto kiekių dinamiką bėgant metams. − Ištyrinėti Lietuvos keliuose ir miesto gatvėse frezuoto bei išlaužto ir sutrupinto naudoto asfalto granulių komponentines sudėtis ir savybes. − Nustatyti pridedamo atnaujinančio bitumo rūšies ir procentinio kiekio įtaką regeneruoto karštai maišyto asfalto (KMA) mišinio fiziniams ir mechaniniams Maršalo rodikliams, taip pat regeneruoto suminio bitumo savybėms. − Nustatyti su skirtingu kiekiu naudoto asfalto granulėmis regeneruoto KMA mišinio atsparumą vėžių susidarymui. − Pateikti naujus deterministinio ir... [toliau žr. visą tekstą]

The research presented in this thesis studies the effects of foamed bitumen on the deformational behaviour and performance of pavement materials. The research was conducted in the laboratory and the field, using specific New Zealand materials. The aggregate used is a blend of a coarse aggregate imported from the Auckland region with a crushed dust from the Canterbury region. The bitumen selected for the study is an 80/100 bitumen grade, and the active filler was a Portland Cement, both commonly used for foamed bitumen stabilization in New Zealand. In the laboratory, samples of mixes with different foamed bitumen content were tested under various loading and stress conditions to investigate the effects of foamed bitumen on the deformational behaviour of the mix. The tests performed were: Indirect Tensile Strength (ITS), Indirect Tensile Resilient Modulus (ITM), Repeat Load Triaxial compression (RLT) and Monotonic Load Triaxial compression (MLT). Preliminary ITS and RLT tests conducted on mixes with 1% and 0% cement, at different foamed bitumen contents, indicated that mixes without cement performed poorly compared to the mixes with 1% cement. Therefore, the rest of the laboratory study was on mixes with 1% cement. ITS tests were conducted on 150 mm specimens prepared with 0% 1%, 2%, 3% and 4% bitumen content, with a common 1% cement. Results indicated that foamed bitumen increases the ITS values of the mix, up to an estimated optimum of 2.8% bitumen content. Similar trends were obtained with ITM tests, in which a diametrical load pulse was applied on 150 mm specimens, showing an estimated resilient modulus peak near to 2.8% bitumen content. RLT specimens were prepared at 0%, 2% and 4% bitumen content, at two compaction efforts, creating specimens at low and high bulk density. Permanent deformation RLT tests involved the application of seven stages of 50,000 load cycles each (4 Hz), with increasing deviator stress (from 75 kPa in the first stage, up to 525 kPa in the seventh stage) and at constant confining pressure of 50 kPa. Results of RLT permanent deformation tests indicated that the increase in the foamed bitumen content resulted in an increase in the permanent deformation of the material. MLT tests were conducted on specimens at 0%, 2% and 4% bitumen contents, at two compaction efforts, creating specimens of low and high bulk density, at confining pressures ranging from 50 kPa to 300 kPa, with a deformation rate of 2.1% per minute. Results indicated that the effect of foamed bitumen was a reduction of the peak vertical stress, or a reduction in the peak strength. The peak stresses obtained in MLT tests were plotted in stress diagrams, and the failure was approximated as linear function of the confining stress. The fundamental shear parameters (angle of internal friction and apparent cohesion) were estimated, and results indicated that foamed bitumen has no apparent effect in cohesion but does reduce the angle of internal friction. The reduction of the angle of internal friction explains the general trends observed in the laboratory, that on one hand the compressive strength decreases with increasing bitumen content, but on the other hand, the tensile strength increases up to an optimum. A full-scale experiment was carried out using an accelerated testing of foamed bitumen pavements at the Canterbury Accelerated Pavement Testing Indoor Facility (CAPTIF). In the full-scale experiments, the same materials that were tested in the laboratory (aggregates, bitumen, cement) were used to construct six different pavement sections, each with different contents of bitumen and cement. Three were constructed using foamed bitumen contents of 1.2%, 1.4% and 2.8% respectively, plus a common active filler content of 1.0% cement. Two more pavements were constructed adding cement only (1.0%), and foamed bitumen only (2.2%). In addition, one control section with the untreated unbound material was tested. Strains were collected using a 3D Emu soil strain system installed in each pavement section. The curing time between construction and pavement loading was approximately three months. The pavement response, such as surface deformation (rutting), surface deflections and strains were periodically recorded during the execution of the test. The strains were collected at different depths by using an array of Emu strain gauges. Deflections were recorded using both a Falling Weight Deflectometer (FWD) and CAPTIF Beam deflectometer, which is a modified Benkelmann beam. A total number of approximately 5.6 million equivalent standard axles were applied on the pavement sections. The rutting measured in the sections stabilised with foamed bitumen and cement was the lowest, showing that the addition of foamed bitumen significantly improved the performance of materials with 1% cement. The sections stabilised with cement only, foamed bitumen only, and the control untreated section showed large amounts of rutting and heaving by the end of the test. Deflection measurements showed that the effect of foamed bitumen content is a reduction of pavement deflections, with the lowest deflection measured in the section stabilised with 2.8% bitumen and 1% cement. The elastic pavement strains showed that foamed bitumen reduced the tensile strains in the basecourse but did not have a significant effect on vertical compressive strains. During the construction of pavements, material samples were taken for ITS and RLT testing. Results indicated that the highest ITS was measured in the section with 2.8% foamed bitumen content and 1% cement, and the ITS in the section without cement and foamed bitumen only was about 4-5 times lower than the ITS measured in specimens with cement. RLT specimens without cement performed poorly in comparison with the specimens with 1% cement. The specimens with 1% cement showed higher permanent deformation with increase in the foamed bitumen content, supporting the results from the previous laboratory study. To interpret and relate the results observed in the laboratory and the field, stress path analysis was used, in which the stress ratio of the foamed bitumen layers was calculated at different depths. The analysis showed that foamed bitumen content decreases the maximum stress ratio, hence reducing the proximity to failure and relative damage of the layer. Three-dimensional and two-dimensional finite element modelling of the CAPTIF pavements, were used to further investigate the stress and strain fields induced by the loading and to explain the pavement performance observed in the full-scale experiment.

Concrete and asphalt are the most common materials used in permanent roadway pavements. Roadways are also constructed for temporary use in the resource industry, for remote site construction, and for disaster relief. Although temporary roads have been used for almost as long as permanent ones, little research has been done to optimize their design in view of their relatively short service lives or to investigate the advantages of constructing them with reusable materials or employing structural systems that require minimal subgrade preparation. With this in mind, the purpose of this study is to conduct research to determine the feasibility of a reusable, modular road plate system requiring minimal preparation of the subgrade. This thesis presents a literature review, summarizing the currently available products that perform a similar function and the methods currently available to design such products, including terramechanics and foundation design. Alternative concept designs for a modular road plate system are then introduced. Following this, a simple structural steel plate system is designed to resist vertical, traffic-induced loads using several methods. Specifically, an equivalent thickness method and finite element (FE) analysis are employed. Different loading conditions, soil conditions, and plate assemblies (i.e. boundary conditions) are compared. The different loading conditions include: single and multi-wheel loading, and centre versus edge loading of the plate. The different modelled plate assemblies include: single plates, four plates assembled with fixed connections, and four plates assembled with hinged connections. Structural steel plates are considered in the FE analysis study, in order to develop the design methodology, prior to applying it to the other materials or structural systems. Soil properties and panel thicknesses are studied covering a broad range of conditions under which temporary roadways may be built. Thirty scenarios are created from five soil types and six panel thicknesses. With the different loading and boundary conditions investigated, a total of 120 scenarios are analyzed in total, using several different FE models. The results from the FE analysis studies show that there is a significant difference between hinged and fixed connected panels, and that these different boundary conditions can be considered by modelling a single plate that is centre loaded (to represent a multi-plate system with fixed plate connections) or a single plate that is edge loaded (to represent a multi-plate system with hinged plate connections). The results of this research in general provide a practical framework for developing a modular road plate system constructed using any material or structural system under a range of soil and loading conditions.

Concrete and asphalt are the most common materials used in permanent roadway pavements. Roadways are also constructed for temporary use in the resource industry, for remote site construction, and for disaster relief. Although temporary roads have been used for almost as long as permanent ones, little research has been done to optimize their design in view of their relatively short service lives or to investigate the advantages of constructing them with reusable materials or employing structural systems that require minimal subgrade preparation. With this in mind, the purpose of this study is to conduct research to determine the feasibility of a reusable, modular road plate system requiring minimal preparation of the subgrade. This thesis presents a literature review, summarizing the currently available products that perform a similar function and the methods currently available to design such products, including terramechanics and foundation design. Alternative concept designs for a modular road plate system are then introduced. Following this, a simple structural steel plate system is designed to resist vertical, traffic-induced loads using several methods. Specifically, an equivalent thickness method and finite element (FE) analysis are employed. Different loading conditions, soil conditions, and plate assemblies (i.e. boundary conditions) are compared. The different loading conditions include: single and multi-wheel loading, and centre versus edge loading of the plate. The different modelled plate assemblies include: single plates, four plates assembled with fixed connections, and four plates assembled with hinged connections. Structural steel plates are considered in the FE analysis study, in order to develop the design methodology, prior to applying it to the other materials or structural systems. Soil properties and panel thicknesses are studied covering a broad range of conditions under which temporary roadways may be built. Thirty scenarios are created from five soil types and six panel thicknesses. With the different loading and boundary conditions investigated, a total of 120 scenarios are analyzed in total, using several different FE models. The results from the FE analysis studies show that there is a significant difference between hinged and fixed connected panels, and that these different boundary conditions can be considered by modelling a single plate that is centre loaded (to represent a multi-plate system with fixed plate connections) or a single plate that is edge loaded (to represent a multi-plate system with hinged plate connections). The results of this research in general provide a practical framework for developing a modular road plate system constructed using any material or structural system under a range of soil and loading conditions.

Overloading truck traffic is an untenable problem around the world. The occurrence of overloaded truck traffic can be evidence of rapid development of an economy. Most of the developing countries emphasize the development of economy, thus supporting reform of infrastructure is limited. This research investigates the relationship between truck overloading and the condition of road damage. The objective of this research is to determine the amount of economic loss due to overloaded truck traffic is. Axle load will be used to calculate the total ESAL to pavement. This study intends to provide perspective on the relationship between change in axle load due to overloading and the resultant service life of pavement. It can then be used in the estimation of pavement damage in other developing countries facing the problem of truck overloading. In conclusion, economical loss was found, which include reduction of pavement life and increase in maintenance and rehabilitation (M&R) cost. As a result, net present value (NPV) of pavement investment with overloading truck traffic is higher than normal truck traffic.

Thesis(M.S.)--Auburn University, 2005. / Abstract. Vita. Includes bibliographic references.