Esta dissertação trata do desenvolvimento de um protótipo de Sistema de Gerência de Pavimentos para a rede de aeroportos militares administrados pelo Comando da Aeronáutica (COMAER) e apresenta uma metodologia para a execução da Gerência de Pavimentos no âmbito do COMAER, a fim de subsidiar a elaboração do Plano Plurianual de Obras da Aeronáutica. Para tanto, foram levantadas as informações disponíveis, bem como o inventário de pavimentos das bases aéreas subordinadas ao Quinto Comando Aéreo Regional (V COMAR), o histórico de condição e de intervenção dos pavimentos dos últimos 5 anos, dados de projeto, custos e tráfego aéreo e, a partir desses elementos e de indicações do desempenho dos pavimentos estudados, foi elaborada uma proposta plurianual de investimentos em termos de obras de conservação, a fim de prolongar a vida útil dos mesmos, permitindo um aproveitamento mais racional dos recursos existentes. Além disso, para integrar as informações fragmentadas entre os diversos elos do Sistema de Engenharia espalhados pelo Brasil, foi desenvolvido um Sistema de banco de dados para possibilitar a consulta e cadastramento das avaliações através da INTRAER, a rede interna do Comando da Aeronáutica. / This dissertation concerns in the development of a prototype of a preliminary Pavement Management System for the network of military airports managed by the Brazilian Air Force (COMAER) and aims to provide a methodology for the implementation of the pavement management within the Brazilian Air Force, in order to support the development of the multi-year plan of works. To do it so, the existing information system and the inventory of airfields pavements subject to the Fifth Regional Air Command (COMAR V) was raised, the history of the condition and intervention of decks in the past five years, project data, costs, air traffic and from these elements and performance measures of the pavements studied was an elaborate multi-year investment proposal in terms of conservation works in order to extend the pavement life wich aim at a more rational utilization of resources. In addition, to integrate the fragmented information between the various links of Engineering System throughout Brazil, it was developed a database system to enable to consult and register evaluations through the INTRAER, the internal network of the Brazilian Air Force.

Esta dissertação trata do desenvolvimento de um protótipo de Sistema de Gerência de Pavimentos para a rede de aeroportos militares administrados pelo Comando da Aeronáutica (COMAER) e apresenta uma metodologia para a execução da Gerência de Pavimentos no âmbito do COMAER, a fim de subsidiar a elaboração do Plano Plurianual de Obras da Aeronáutica. Para tanto, foram levantadas as informações disponíveis, bem como o inventário de pavimentos das bases aéreas subordinadas ao Quinto Comando Aéreo Regional (V COMAR), o histórico de condição e de intervenção dos pavimentos dos últimos 5 anos, dados de projeto, custos e tráfego aéreo e, a partir desses elementos e de indicações do desempenho dos pavimentos estudados, foi elaborada uma proposta plurianual de investimentos em termos de obras de conservação, a fim de prolongar a vida útil dos mesmos, permitindo um aproveitamento mais racional dos recursos existentes. Além disso, para integrar as informações fragmentadas entre os diversos elos do Sistema de Engenharia espalhados pelo Brasil, foi desenvolvido um Sistema de banco de dados para possibilitar a consulta e cadastramento das avaliações através da INTRAER, a rede interna do Comando da Aeronáutica. / This dissertation concerns in the development of a prototype of a preliminary Pavement Management System for the network of military airports managed by the Brazilian Air Force (COMAER) and aims to provide a methodology for the implementation of the pavement management within the Brazilian Air Force, in order to support the development of the multi-year plan of works. To do it so, the existing information system and the inventory of airfields pavements subject to the Fifth Regional Air Command (COMAR V) was raised, the history of the condition and intervention of decks in the past five years, project data, costs, air traffic and from these elements and performance measures of the pavements studied was an elaborate multi-year investment proposal in terms of conservation works in order to extend the pavement life wich aim at a more rational utilization of resources. In addition, to integrate the fragmented information between the various links of Engineering System throughout Brazil, it was developed a database system to enable to consult and register evaluations through the INTRAER, the internal network of the Brazilian Air Force.

Master of Science / Department of Civil Engineering / Major Professor Not Listed / With recycled concrete aggregates (RCA) becoming a more popular and cost effective alternative to virgin aggregate, the Kansas Department of Transportation (KDOT) looks to incorporate these aggregates into Portland cement treated base (PCTB). KDOT currently practices a freeze-thaw method that includes 90 days of curing and a maximum of 660 freeze-thaw cycles to determine the durability of its concrete pavements and bases. An experimental study was conducted to determine if lower quality RCA would be an adequate replacement for virgin aggregates within PCTB. Two sources of D-cracked aggregate from “D” cracked pavements, were acquired and used to batch the PCTB. Control samples were batched using virgin aggregates following the gradation of the two sources of RCA. Following the procedure laid out by KDOT, both the RCA and control samples were tested for durability. The results showed that increasing the total amount of cementitious binder in the PCTB increased the durability. Also at lower binder contents, the type of RCA had an impact on the performance of the base containing RCA. In addition, the RCA and control samples had similar performance, and as a result RCA could be a viable aggregate source for PCTB. Finally, it was determined that different criteria need to be developed for the freeze-thaw durability of PCTB as mass loss was an important factor for PCTB with D-cracked aggregates

The proper densification of the separate pavement layers forms an integral part of road construction. Many problems, are, however, experienced in this area. Because of a lack of knowledge the compaction of untreated roadbuilding materials in problem situations is usually approached on a ''trial and error'' basis rather than basing possible solutions on scientific evidence of the collective influence of the material properties and site conditions. The purpose of the study was to place the compaction of untreated roadbuilding materials on a more scientific basis. An investigation was therefore launched to determine the effect of measured material properties on their compactability. A non-standard vibratory compaction test was used to compact the samples in one layer. New test parameters to quantify the shape and texture of the material were also developed, namely the shakedown bulk density and the shape factor. The CBR values of the materials at moulding moisture content were determined for each material for a range of densities and moisture contents. The maximum dry densities (MOD) (vibratory and mod. AASHTO) and optimum moisture content (OMC) (vibratory and mod. AASHTO) were also determined. The measured values were then evaluated in terms of the following physical properties of the materials: grading, Atterberg limits, linear shrinkage, shakedown bulk density (SBD), loose bulk density (LBO), shape factor (SF) and specific rugosity (Srv). In the extensive laboratory study of 21 different untreated roadbuilding materials, varying from TAB classes A-7-6 to A-1, it was found that both the maximum dry densities and moisture regimes can be quantified in terms of the grading, liquid limit and linear shnnkage of the materials. These relations were modelled by means of regression analysis. Besides this a general bearing capacity model was found for all these materials where the CBR is a function of the dry density and moisture content of the material. This model was further refined to take account of the influence of shape and texture of the particles so that it is possible to determine reasonable estimates of the bearing capacity for a range of densities and moisture contents from the grading, Atterberg limits, linear shrinkage, shakedown bulk density and shape factor. This investigation has shown that physical laws govern both the compactability and bearing capacity of untreated roadbuilding materials, irrespective of their composition or nature, making it possible to approach the compaction of untreated roadbuilding materials in a more generalised manner. / Thesis (PhD)--University of Pretoria, 1991. / gm2014 / Civil Engineering / unrestricted

In Mpumalanga, only about 25 per cent of households have car access, which makes Mpumalanga one of the provinces with the highest use of public transport by means of bus or taxi in South Africa. Even though the road network in Mpumalanga is extensive, the maintenance and upgrade of this network is a concern, especially for municipal and provincial roads. Deteriorating roads have a direct (such as vehicle operating costs, VOCs) and indirect impact (such as high bus fares) on the road user. This study focuses on the interaction between one bus from Buscor and the pavement surface of one specific bus route, including the associated VOCs generated. The ride comfortability of the bus route was evaluated by interpreting International Roughness Index (IRI), Power Spectral Density (PSD), and vertical accelerations (awz) data, after which the associated vehicle operating costs (VOCs) for the bus were projected. The judgement of ride comfortability in a vehicle is an area of controversy, and studies on this topic dates back from the 1920sThe threshold values from ISO (1997), Cantisani, and Loprencipe (2010) were used for the purposes of this study. The vertical accelerations generated from the surface of the bus route, for a bi-articulated bus were measured with accelerometers. The accelerometers were placed on the bus where the vertical accelerations were expected to be the highest. The identified bus route included different roads with different responsible authorities and roughness levels. A profiler conducted a survey on the route and five different sections were identified. The collected data were analysed with various programs. From the data collected from the accelerometers the PSD, awz, and the speed that the bus travelled on each section could be determined. The IRI data for each section was categorised in three categories, very good to good, fair to mediocre and poor. Anomalies in each section were identified, and the cause of these anomalies determined. The anomalies were analysed with the data, as these values formed part of the route. The impact of road roughness on fuel consumption, tyre wear and repair and maintenance costs were analysed. The calibrated Highway Development and Management System (HDM 4) model was used to predict the fuel consumption, tyre wear and repair and maintenance cost per km of each section of the bus route under consideration. In this analysis, the impact of the vehicle speed proved to be significant, as it affected the PSD values, the awz values and the VOC. The scenario was analysed to improve the riding quality of the two worst sections of the bus route, and by improving the road surface of these two sections, travel time could be reduced and costs could be saved. The scenario of an increase in road roughness was also analysed, to indicate the percentage of increase in costs, if these roads kept deteriorating. The analysis showed a significant increase in repair and maintenance cost, fuel consumption, and tyre wear. The limitations of this study included some correlation issues with the profiler data and the accelerometer data, unidentified bus stops on gravel shoulders, and the suspension system and interior of the bus that were deemed constants and not variables within the scope of this study. Despite these limitations, there are still a number of possibilities with the data collected. Apart for the analyses conducted for the study, recommendations for further refinement include the impact of bus mass on the data (full bus versus empty bus), the suspension type and condition, the interior of the bus, trip duration and congestion, evaluation of driver fatigue, tyre pressure and dynamic wheel loads, and safety. Furthermore, the construction cost of upgrading the two worst sections of the route versus the increase in VOCs because of the deteriorating state of the route could be investigated. In conclusion, the speed played a determining role in the generation of vertical accelerations, therefore user comfort or discomfort, and VOCs. An increase in IRI indicates deteriorating riding quality that affects the comfortability of a ride and the VOCs negatively. IRI can be used to determine the state of the road and qwz gives an indication of the comfortability of a ride. / Dissertation MEng--University of Pretoria 2014 / ay2014 / Civil Engineering / unrestricted

This thesis investigates the effects of using various percentages of RAP and asphalt binder contents on the dynamic modulus and fatigue resistance of asphalt concrete. Two RAP percentages (20% and 40%) and three binder percentages (plant-mixed, plant-mixed + 0.5%, and plant-mixed + 1.0%) were evaluated. A Superpave gyratory compactor and an asphalt vibratory compactor were used to prepare dynamic modulus samples and fatigue beam samples at 7% air voids. Three replicate samples for each percentage of RAP and asphalt binder content were prepared for testing purposes. An Interlaken Technology Corporation servohydraulic testing machine and a Material Testing System servohydraulic machine were used to determine the dynamic modulus and fatigue resistance of the asphalt samples. Analysis of variance (ANOVA) was used to determine if any of the factors (air voids, percent RAP, and percent asphalt binder) affected the performance criteria (dynamic modulus and fatigue life cycles). Results suggest that as the amount of RAP increases in asphalt concrete, both the dynamic modulus and fatigue life will increase. As per the literature, these results were expected for the dynamic modulus, but not for the fatigue life. It is suspected that the increase in fatigue life for the 40% RAP mixes may be due to the use of a softer binder (PG 64-22 instead of PG 70-22).  It was also found that by increasing the amount of binder in the mixture, the stiffness of asphalt concrete will decrease, but the fatigue life will improve. The fatigue life results showed a strong trend of this improvement for the 20% RAP samples, however, the results for the 40% RAP samples were inconclusive. For dynamic modulus, it was found that the percent RAP, additional binder, frequency, and temperature were all statistically significant with 95% confidence. For the fatigue life, ANOVA showed that the percent RAP and additional binder were statistically significant with 95% confidence. These results suggest that by utilizing a higher percentage of RAP and asphalt binder, it is possible to meet or improve upon the dynamic modulus and fatigue life of the lower percentage of RAP samples. / Master of Science

Reclaimed asphalt pavement (RAP) is a valuable resource that can be recycled into new asphalt mixtures. In recent years, the continued rise of raw material costs has generated considerable interest in increasing RAP usage. Warm mix asphalt (WMA) is a modern development in the asphalt industry that can potentially help increase RAP usage and achieve adequate mixture performance. The purpose of this dissertation is to: 1) develop a method to characterize the absorbed, inert and effective bituminous components in RAP; and 2) evaluate performance of high RAP-WMA mixtures for various pavement applications including airfield surfaces, highway surfaces and highway bases. A unique approach was taken to characterize RAP properties that coupled a dataset of 568 asphalt mix designs spanning five years of practice and testing 100% RAP with added virgin binder; 394 compacted specimens and 68 loose specimens were tested. A method to predict RAP absorbed asphalt was developed and shown to yield more reasonable results than conventional methods which were shown very likely to give incorrect absorbed asphalt contents in some conditions. The relative effectiveness of RAP surface asphalt was evaluated and estimates of inert and effective RAP asphalt were made for a variety of temperature, compactive effort, and warm mix additive conditions. Results showed different behaviors between RAP sources and between hot and warm mix temperatures. These results were also observed in volumetrics of high RAP mixtures. Performance evaluation was based on testing 75 slab specimens and more than 1100 gyratory specimens. Test data indicated a potential for decreased durability as RAP content increases; however 25% RAP highway surface mixtures and 50% RAP base mixtures had similar performance to current practice. Low temperature mixture stiffness testing and thermal cracking analysis indicated slightly increased stiffness with high RAP and 25% RAP highway surface mixtures that had comparable performance to current practice. Dry rut testing indicated high RAP mixtures are rut resistant. Moisture damage testing of high RAP mixtures indicated passing results in tensile strength ratio testing but potential for moisture damage in loaded wheel tracking. Overall, 25% RAP highway surface mixtures are recommended for immediate implementation.

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Foamed asphalt stabilized material as a high quality granular base incorporating high percentages of fine fractionated reclaimed asphalt material is investigated. A foamed asphalt mix is designed using a fabricated asphalt foaming device. The final specimens are tested for indirect tensile strength, indirect tensile resilient modulus, triaxial resilient modulus, triaxial repeated load permanent deformation, and unconfined compression. Results are compared to those with the same aggregate blends without stabilization for triaxial resilient modulus and repeated load permanent deformation. Stabilized materials are tested in soaked and unsoaked states to establish moisture susceptibility. Foam stabilization is found to significantly improve triaxial resilient modulus in all materials as well as permanent deformation resistance in materials with high RAP content. Soaking only marginally reduces triaxial resilient modulus and the effects are lesser in materials incorporating high RAP content. / Thesis / Master of Applied Science (MASc)

No description available.