Pavement Reconstruction Research Articles

Case Study on the Effect of Recycled Asphalt Layer Parameters on the Bearing Capacity of the Pavement

Numerous ways to use recycled asphalt (RA) in the road base course will provide both environmental and economic benefits, allowing to recycle and utilise this initially waste material in road or pavement reconstruction projects. However, the properties and parameters of RA necessary for the application of reclaimed asphalt pavement (RAP) in a new pavement structure in most cases are not detectable in the design stage, which complicates design and construction process. The purpose of this paper is to study possibilities for evaluating the performance and parameters of RA, as well as to review the possibilities, methods and applications for RA testing. Data for this case study were obtained from recently completed road structures in the form of FWD measurements, together with lab explored parameters of drilled pavement cores. Based on that data, the relationships between the main pavement structural parameters, such as modulus on the surface of the pavement, compressive strength of RA core segment, thickness of bound layers and back calculated modulus were examined. On the way to exploring different analytical approaches, two approximation models were developed and compared, using the obtained data: by directly approximating the obtained data and after processing them with artificial neural network (ANN).

Field and numerical investigation of full depth reclamation with Portland cement in Georgia

The Full Depth Reclamation (FDR) technique has recently become a popular rehabilitation method to reconstruct old flexible pavement. Pulverized existing roadway materials are blended with stabilizing agents such as foamed asphalt and Portland cement to form a stiff base course for the new pavement. In Georgia, Portland cement is commonly used as a stabilizing agent for FDR stabilization. One of the challenges in FDR stabilization projects is to achieve uniform stiffness throughout the stabilized layer. FDR mix design often specifies a fixed rate of stabilizing agent, which could generate a range of FDR strengths due to the inherent variability in the existing pavement. Stiffness variation in the stabilized base should be minimized for optimum long-term pavement performance. This study investigates the influence of the variability in the FDR base layer stiffness on pavement performance. A series of field and laboratory tests were performed on a pavement reconstruction project in Georgia to assess variability. Tests included Unconfined Compressive Strength (UCS) tests and deflection tests with a Light Weight Deflectometer (LWD) and Falling Weight Deflectometer (FWD). Mechanistic sensitivity analyses were performed based on the field and laboratory test results to investigate the effect of variability in FDR properties on pavement performance. The results indicate both the FDR base thickness and strength have a significant influence on the predicted pavement responses. Findings presented here will be of interest to pavement engineers involved in the design and performance modeling of FDR pavement.

Local Versus Full Width Pavement Rehabilitation in the Frame of Old Water Supply Network Repair

Since the global financial crisis of 2008, all construction related activities are now subject to cost control of each project. An important component of the optimal choice is the implementation cost. The evaluation of construction activities can be conducted by estimating their environmental as well as their cost footprint, which is also the demand and consumption measure for the societies' needs. Water and sewerage projects have a key role in the standard of living, Public Health and environment. Therefore, water supply network replacements are important to upgrade the quality and quantity of water, through cost-effective choices. The purpose of this study is to present and comment on the uniform cost footprint through the complete replacement of the old water supply network along with complete reconstruction of pavement compared to local repair activities. Usual practices in repair works of old networks and flexible pavement rehabilitations are presented, assessing the benefits of total reconstruction by carrying out life cycle cost analysis in terms of uniform cost per year. The project of replacing the water supply network in the municipality of Larissa, Greece for the period 2015-2019 is analyzed, linking water savings with simultaneous total pavement rehabilitation, calculating average cost per inhabitant and hydrometer, comparing cost and pavement surface area between total and localized rehabilitation activities for a twenty-year rollback period. The fruitful findings of this research study, indicate that full-width pavement rehabilitation along with new water supply network establishment is economically advantageous compared to local rehabilitation treatments, according to the time period considered. Thus, competent authorities can use the proposed methodology as a useful tool to conclude to the optimal choice for maintaining water supply networks in a cost-effective way.

Use of tung oil as a rejuvenating agent in aged asphalt: Laboratory evaluations

One of the most effective measures to utilize abundant reclaimed asphalt pavement (RAP) materials, generated by the maintenance and reconstruction of asphalt pavements, is to employ rejuvenating agents. This study recognized tung oil as a rejuvenating agent and four different tung oils (2%, 4%, 6%, 8%, by weight.) blended with aged asphalts were carried out to assess the effect of tung oil on the performance and characteristic functional groups of Pen70 aged asphalt and SBS modified aged asphalt. Desired contents of tung oil were decided preliminarily by conventional property tests involving penetration, softening point, ductility, and rotational viscosity. Afterward, dynamic shear rheometer (DSR) tests including temperature sweep and frequency sweep and bending beam rheometer (BBR) tests were conducted, and Fourier transform infrared spectroscopy (FTIR) tests were implemented to analyze rheological properties and characteristic functional groups of original asphalt, aged asphalt and rejuvenated asphalt, respectively. Experimental results indicated that the addition of tung oil could enormously ameliorate the flexibility of aged asphalt, and suitable contents of tung oil can ensure the high-temperature performances of rejuvenated asphalts. Meanwhile, rejuvenated asphalt performed a better low-temperature cracking resistance than that of virgin asphalt from the test results of BBR. The stiffness of rejuvenated asphalts concluded by master curves is even higher than their corresponding virgin asphalts due to suffering aging, meaning they have lower temperature sensitivity. Also, Carbonyl and sulfoxide index of the Pen70 aged asphalt could be effectively abated by mixing with tung oil, but the existence of tung oil may interfere the test results of FTIR of SBS modified aged asphalt.

Проект реконструкції Шахтарського бульвару в місті Вугледар Донецької області

Проаналізовано сучасний стан озеленення території Шахтарського бульвару в місті Вугледар Донецької області. Ландшафтний аналіз території об'єкта показав, що Шахтарський бульвар, розташований у центрі міста Вугледар Донецької області, має регулярний стиль планування. Встановлено, що в балансі території бульвару споруди займають 1,3 %, дорожньо-стежкова мережа – 27,8 %, деревно-кущові насадження – тільки 5 %, квітники – 1,5 %, деградовані газони та пусті ділянки – 64,4 %, що не відповідає нормативам озеленення, прийнятим в Україні. Окрім цього, відсутні водні облаштування; недостатньо таких елементів благоустрою, як: лави, ліхтарі та урни; відсутній тротуар вздовж південної сторони бульвару. Проведено інвентаризацію деревних і чагарникових порід. Складено інвентаризаційну таблицю зелених насаджень, на основі якої зроблено висновки та внесено пропозиції щодо реконструкції та відновлення зелених насаджень та благоустрою території. Реконструкція озеленення території Шахтарського бульвару полягатиме у створенні нових декоративних насаджень. Для озеленення території підібрано асортимент рослин згідно з ґрунтово-кліматичними умовами району. Планування території здійснено за допомогою застосування різних типів і форм рослинних насаджень: алей, груп, солітерів, газонів, живоплотів та бордюрів, квітковим оформленням ділянки та вертикального озеленення. Проектними пропозиціями передбачено висадження 438 саджанців дерев, 4512 кущів, 24 ліани, 758 саджанців троянд і 746 однорічників, цибулинних квітів і трав'яних багаторічників.

A new data preprocessing method for 3D reconstruction of pavement

ABSTRACT Three-dimensional (3D) reconstruction of pavement surface based on the laser scanning can be used to extract the elevation information for evaluating the damage degree of the pavement. This technology is of great significance to road safety as well as the advances of smart transportation. The preprocessing procedures of the laser-scanned point cloud serve as the basis for accurate surface reconstruction, which includes outlier removal, smoothing and sampling. In view of the limitations of the existing preprocessing methods for pavement applications, this paper proposes a new preprocessing method. First, a local density-based outlier removal algorithm is used to solve the problem of poor adaptability or long computation time of the regular outlier removal algorithms. And then, a continuous algorithm based on the moving least squares method is used to smooth and sample the points, solving the problem of repeated degradation of the data. Finally, the field tests on three types of pavements are carried out to verify the feasibility of the proposed preprocessing method. The accuracy of the reconstructed surfaces of the pavements is improved by the new preprocessing method.

Удосконалення методу оцінки стійкості покриття нежорсткого дорожнього одягу до утворення колії

Introduction. The experience of road operations of recent years shows that one of the most common defects in asphalt pavement under the impact of traffic loads and high summer temperatures is rutting which leads to decrease of its life time and, respectively, the road pavement design as the whole. The need to improve the method of evaluation of stability of non-rigid pavement against the rutting is determined. Problem statement. Taking into account that non-rigid pavement is in complicated operational conditions (it is confirmed by intensive growth of defects, such as rutting) due to increase of traffic loads and high summer temperatures, it is needed to increase the stability of non-rigid pavement against rutting. Purpose. Purpose is to improve the method of assessing the stability of the non-rigid asphalt pavement against rutting under the impact of vertical loads of vehicles at high summer temperatures. Materials and methods. Methods of research are analytical and experimental using the provisions of the theory of elastic plasticity and thermal elasticity and experimental methods of studying the rutting formation in non-rigid asphalt pavement; methods of numerical simulation; methods of mathematical statistics. Results. On the basis of the performed analysis, the working conditions of non-rigid pavements were considered, as well as the existing theoretical and experimental methods of forecasting the rutting formation was analyzed. Analytical dependency is achieved and method of evaluation the stability of non-rigid pavement against rutting under the impact of vertical vehicle loads is improved that allow considering the complex impact of major factors, namely: thermo viscous elastic properties of asphalt, soil stabilization, asphalt temperature, vertical pressure on pavement of vehicle tires, intention of vertical pressure, time of load impact. The calculated thermoreological characteristics of asphalt concrete and reinforced soils, the adhesion strength between asphalt and the foundation during shearing were experimentally researched. Field, laboratory and bench tests of the impact of various factors on the formation of residual strains in the form of rut were carried out, as well as the regularities of impact of influence factors on the intensity of the rutting formation in non-rigid asphalt pavement. Conclusion. During work, the method of evaluation of the stability of the non-rigid pavement against the rutting was improved and the complex impact of the main factors was considered, namely: thermo viscous elastic properties of asphalt concrete, vertical pressure of vehicles on the pavement and the time of its impact on the structure; the intensity of vertical loadings. The results of research were used in the development of regulations for the design, construction, reconstruction, repair and operation of asphalt pavements on highways of Ukraine.

Analysis of the operating conditions of mobile composite airfield pavements

Safety maintenance is a key and essential condition for flight operations performance by aircraft. It refers to all functional elements of an airport, i.e. runways, taxiways and aprons, as part of the movement area at civil, as well as military airports. Airfield pavements, likewise the aircraft and technical personnel of ground control directly affecting the safety of flight operations, are the integral part of each functional element of an airport. Airports in the event of force majeure, critical events and foremost, in the event of war threat are the facilities that would be the first objects to focus on. As a result, airfield pavements constructions would be destroyed and require quick reconstruction that guarantee its restoration of operational readiness and safety conditions for operating aircraft. Existing technology and methods of airfield pavement reconstruction could not meet the stringent time requirements of military operations, that is why mobile, composite airfield mats have been developed. In the paper, operational and maintenance advantages of the elastic, mobile airfield mat ELP-1 KRATER manufactured by Shipyard Żuławy are shown. There is presented the computational model of composite pavement which co-operates with subbase and also shown are the results of field tests, performed by the Air Force Institute of Technology. Moreover, there are presented the results of load-bearing capacity of the composite airfield mat ELP-1 KRATER received during field tests.

Recycling of Materials for Pavement Dressing: Analytical Review

The paper presents an analytical review of materials recycling for pavement dressing. Recycling or repeated usage of pavement dressing materials while making reconstruction and repair of road pavements is not considered as a new conception and it has been realized in various countries of the world since 20th century. Recycling (hot, cold) is based on methods of its execution, properties of pavement dressing materials which are subjected to processing and which influence on the quality of final material, technical and operational indices, specific economic efficiency. Investigations on the processes of structure formation, thermo-physical properties in components based on granulates of transformed pavement dressings during recycling demonstrate that regeneration makes it possible to attain 100 % recovery of material properties for road pavement base. The paper describes other factors which represent a complex of challenges concerning exterior and internal problems. These problems have arisen due to actual processes of heat and mass transfer in one layer, multi-layer systems of pavement dressings. At known coefficients of heat conductivity, steam- and mass permeability, diffusion, filtration, temperature conductivity, density of material layers etc. initial and boundary conditions it is possible to carry out optimization of heat- and mass transfer problems from bottom surface of road layer to its base (sand, bulk materials, ground). In addition to it, while taking into account development of scientific prospective direction that concerns nano-technology and creation of nano-materials for higher reliability of road dressings it is necessary to consider nanomaterial science in road-construction industry as the most actual one because when we study problems pertaining to fractional composition of all road dressing components including transfer to nanomaterials, for example, application of modified water-reducing agent based on nanostructured carbon it is possible significantly to increase physical and technological properties of asphalt concrete and concrete road dressings. The paper reveals that it is necessary to continue and expand study of physical and technical and thermophysical properties of new materials on the basis of nano-technologies with application of modified, nanostructured carbon-based plasticizer for construction-road industry because especially these additives significantly increase cement activity that leads to improvement of strength, reliability and longevity for the obtained materials.

Pavement Management System Investigation in Case of Afghanistan

Afghanistan is encountering a massive compete in arrangement of old infrastructure. Specially for roads structure, it is found that many roads pavements built 30 to 40 years ago and now it is the end of their life. Other roads had been deteriorated because of misuse, overuse and mismanagement and also after more than 3 decades of conflict Afghanistan encountered keen challenges in rehabilitation and reconstruction of the roads. In addition, present and future threats influence the wished mission of these pavements for fast, safe and comfort transportation of people and goods. Moreover, the current management shows that the system is being used now is not flexible enough to consider on the changing conditions and is poor to assist in making decisions.This study aims to initiate a Pavement Management System by providing an organized procedure of maintaining, reconstructing, and operating the roads pavements and to utilize in a better flexible strategy that can enable this research to perform better tasks, more economically, higher quality and do it such a manner to achieve a desired result.A system has been also presented to help and make easier the decision making process. It is Micro PAVER pavement software. Micro PAVER is a Pavement Management System developed by the US Army Corps of Engineers. Micro PAVER provides pavement management capabilities to:· Organize and develop the pavement list.· Analyze the running condition of pavements.· Develop methods to forecast future conditions report on past and future pavement execution; and· Develop plots for pavement maintenance based on condition needs or budget. Therefore, in order to have a good management system, this system will be preferred which provide an organized method of maintenance, reconstruction and operation of the roads pavements. And the system will be flexible enough and assists in making decisions.

The Use of Laboratory-Measured and Strain-Gauge Backcalculated Asphalt Stiffness for Rutting Performance Prediction

Laboratory tests are conducted with asphalt concrete materials to determine the expected in-situ performance. In addition, laboratory test results are commonly used in mechanistic-empirical design methods for material characterization to improve the predictive accuracy of the models. However, the effectiveness of laboratory tests in characterizing the long-term performance of asphalt concrete materials needs to be validated to be able to use the results for pavement design and long-term performance prediction. Inaccurate performance characterization and prediction can directly affect the decision-making process for pavement maintenance, rehabilitation, and reconstruction and result in unexpected early failures in the field. The major objective of this study is to determine the impact of using laboratory-measured asphalt stiffness on the prediction accuracy of mechanistic-empirical models. In addition, the effect of using linear-elastic modeling assumptions (layered elastic theory) and neglecting the nonlinearity of pavement response at high load levels (and/or at high strain levels for weaker structures) on the predicted rutting performance was determined. In this study, the effectiveness of the use of laboratory asphalt stiffness tests for in-situ asphalt stiffness characterization was determined by comparing the rutting performance predicted using laboratory-measured stiffness to rutting predicted using strain-gauge backcalculated stiffness. It was determined that laboratory tests are able to characterize the in-situ stiffness characteristics of the asphalt mix used in this study and the stiffness characterization process suggested in this study can provide reliable rutting performance predictions. Results of this study are only applicable to tested rubberized asphalt concrete mixtures.

Variable impact transportation (VIT) model for energy and environmental impact of hauling truck operation

Fuel economy and emissions of heavy-duty trucks greatly vary based on vehicular/environmental conditions. Large-scale infrastructure construction projects require a large amount of material/equipment transportation. Single-parameter generic hauling models may not be the best option for an accurate estimation of hauling contribution in life cycle assessment (LCA) involving construction projects; therefore, more precise data and parameterized models are required to represent this contribution. This paper discusses key environmental/operational variables and their impact on transportation of materials and equipment; a variable-impact transportation (VIT) model accounting for these variables was developed to predict environmental impacts of hauling. The VIT model in the form of multi-nonlinear regression equations was developed based on simulations using the U.S. Environmental Protection Agency (EPA)’s Motor Vehicle Emission Simulator (MOVES) to compute all the impact categories in EPA’s TRACI 2.1 and energy consumption of transportation. Considering actual driving cycles of hauling trucks recorded during a pavement rehabilitation project, the corresponding environmental impacts were calculated, and sensitivity analyses were performed. In addition, an LCA case study based on historical pavement reconstruction projects in Illinois was conducted to analyze the contribution of transportation and variability of its impacts during the pavements’ life cycle. The importance of vehicle driving cycles was realized from simulation results. The case study results showed that considering driving cycles using the VIT model could increase the contribution of hauling in total life cycle Global Warming Potential (GWP) and total life cycle GWP itself by 2–4 and 3–5%, respectively. In addition to GWP, ranges of other hauling-related impact categories including Smog, Ozone Depletion, Acidification, and Primary Energy Demand from fuel were presented based on the case study. Ozone Depletion ranged from 9 to 45%, and Smog ranged from 11 to 48% of the total relevant life cycle impacts. The GWP contribution of hauling in pavement LCA ranged between 5 and 32%. The results indicate that the contribution of hauling transportation can be significant in pavement LCA. For large-scale roadway infrastructure construction projects that need a massive amount of material transportation, high fidelity models and data should be used especially for comparative LCAs that can be used as part of decision making between alternatives. The VIT model provides a simple analytical platform to include the critical vehicular/operational variables without any dependence on an external software; the model can also be incorporated in those studies where some of the transportation activity data are available.

Improving microwave heating efficiency of asphalt concrete by increasing surface magnetic loss of aggregates

To improve microwave heating efficiency of asphalt pavement, a new technique was proposed by coating a very thin layer of magnetic Fe3O4 films on coarse and fine aggregates, using chemical co-precipitation reaction. The microwave healing effects of modified asphalt mixtures were tested via three-point bending fatigue test and flexural failure test. The results showed that the surface temperatures rates of the asphalt concrete specimens with both modified coarse aggregates (Type C) and modified fine aggregates (Type F) were 0.72°C/s after microwave heating for 2 min, which were 45.8% higher than those of the ordinary asphalt concrete (Type O). The microwave healing indexes of Type C and Type F were 87% and 84%, respectively, about four times as much as those under room temperature. The flexural strength recovery rates of Type C and Type F recovered to 75% in the first damage–heal cycle but decreased to 60% in the second cycle. In addition, the pavement performances of the modified specimens have not been reduced by the surface modification method. In view of the significant improvement of the microwave healing efficiency of asphalt mixtures, this suggested preparation principle is expected to be widely used in the repair and reconstruction of asphalt pavement.

A Tale of Two Pavements: Forensic Investigation of an Unbonded Concrete Overlay and a Concrete Pavement Reconstruction on I-40 near Flagstaff, Arizona

In 1990, the Arizona Department of Transportation (ADOT) constructed a Specific Pavement Studies (SPS)-6 experiment on eastbound Interstate 40 (I-40) east of Flagstaff, AZ, as part of the Long-Term Pavement Performance Program. The SPS-6 experiment was designed to evaluate treatment and rehabilitation options for an existing concrete pavement. Nineteen sections were constructed, one of which was a 10 in. thick unbonded concrete overlay (UBCOL). Additionally, ADOT planned to construct an 11 in. unbonded portland cement concrete (PCC) overlay on the adjacent I-40 westbound to investigate benefits of additional concrete thickness. The eastbound unbonded PCC overlay has significantly outperformed all other pavement sections and remains in good condition after 27 years of service. However, the westbound PCC section is severely distressed and in need of immediate rehabilitation. An investigation was conducted to evaluate why two similar unbonded PCC overlays performed with vastly different results. It was found that the westbound “unbonded PCC overlay” was not an overlay after all, but instead a 12 to 13 in.thick jointed plain concrete pavement (JPCP). The high level of distress in the westbound JPCP is likely related to the presence of a weak subgrade that infiltrated the aggregate base. Additionally, during coring, water filled the core holes suggesting that the subgrade in the westbound direction was saturated. Further, petrographic analysis indicated deicing chemicals contributed to corrosion of the dowel bars and deterioration of the concrete joints. This investigation demonstrates some advantages for using unbonded overlays as rehabilitation alternatives for existing concrete pavements.

Performance of reclaimed asphalt pavement reinforced with Bamboo geogrid and Bamboo geocell

ABSTRACTPerformance of reclaimed asphalt pavement (RAP) reinforced with Bamboo geogrid and Bamboo geocells based on laboratory model tests are presented in this paper. RAP materials are obtained as waste materials during milling and/or full depth reconstruction of bituminous pavement. Generally, very high-quality uniform RAP is used in the preparation of hot mix asphalt (HMA). RAP materials not suitable for preparation of HMA can be economically utilised for the construction of sub-base/base course of flexible pavement. However, the load-settlement behaviour of unreinforced RAP used in base/sub-base of flexible pavement especially placed over softer subgrade is not very encouraging. The same has been improved by reinforcing it with Bamboo geogrid having tensile strength of 100 kN/m and Bamboo geocells in the present study. A series of laboratory model experiments have been conducted using RAP materials with and without the use of reinforcements and placing it over soft marine clay with low california bearing ratio value. Based on model tests results, it is observed that load carrying capacity of RAP increases by about 80% when RAP is reinforced with Bamboo geogrid and Bamboo geocells.

COMPARATIVE ANALYSIS OF PAVEMENT RECONSTRUCTION METHODS

The article deals with pavement reconstruction methods. Hot and cold recycling technologies are compared. Such technologies ensure significant savings compared to complete reconstruction and placement of additional layers on top of the existing pavement. They also allow restoring road pavements according to high quality standards, within the shortest time possible and with minimum impact on the pavement. Examples of implemented pavement reconstruction projects using recycling are given.

A Project-Based Sustainability Rating Tool for Pavement Maintenance

Abstract Pavements require maintenance to prevent undue distress or to restore performance; however, pavement maintenance and its impacts do not receive enough attention in many cases, and are either ignored or treated as a low priority. Most current maintenance activities have budget issues and only focus on removing deteriorated pavement sections. Deferred pavement maintenance has impacts on the environment and on society, and may thus affect the costs associated with maintenance. A sustainability rating tool is a good way to list, explain, and evaluate such impacts. Various sustainability rating tools have been developed for pavement; however, pavement maintenance has its own features that are different from those of the new construction, expansion, or reconstruction of pavements. This research project reviews nine sustainability rating tools for pavement, although none of these tools fully describe maintenance features or can be directly applied to evaluate maintenance projects. A new sustainability rating tool is then developed for pavement maintenance; this new tool can be used to evaluate individual projects and raise public awareness about the importance of pavement maintenance. Its details are described, and its use is demonstrated through an example to show the evaluation process and results.

Stability analysis of anisotropic granular base layers in flexible pavements

Abstract The structural integrity of the unbound granular layers is of paramount importance for the design and analysis of multi-layer structures. The passage of slow moving vehicles in overload corridors can potentially compromise the stability of pavement foundations, and incur unforeseen costs to the travelling public. The likelihood of the destabilizing effect of overload traffic is more pronounced upon moisture intrusion due to infiltration or evapotranspiration. Additionally, due to the temperature and loading rate dependency of viscoelastic bituminous surface layers, the stresses transferred to the supporting granular layers will be more taxing in hot summer months. Therefore, it deems necessary to establish a mechanistic framework to characterize the synergistic influence of the moisture ingress and the parameters of the stress path to ensure the longevity of the granular layers. This research strives to bridge this gap by the development of an anisotropic protocol for the stability control of the granular layers. To achieve this objective, the anisotropic elasticity principles were employed to characterize the proximity of the applied stresses to the strength envelope of the particulate soils. The stability analysis presented in this research underscored the systematic error associated with isotropic characterization of granular layers. The numerical simulations showed that isotropic characterization of the base layer can potentially overestimate the structural capacity of unbound granular layers. This can manifest itself in premature failure of the pavement foundations. The findings of this research can be utilized by the pavement design industry and practitioners to mitigate costs associated with reconstruction and repair of pavements.

Mobile Composite Airfield Element of Security and Reliability in Air Transport

Abstract The problem of safety of the flight operations will be valid as long as there will be aviation, both civil and military. Ensuring the safety was, is and will be one the most important issues in the functioning and development of aviation. The safety of flight operations affect the implementation of all the elements involved in this process, which can be summarized in three groups, namely: man, the aircraft and the environment, including airfield pavements. Airfield pavements are elements that can be intentionally destroyed by military action as well as a result of random unexpected situation (failure, catastrophe, natural disaster). The reconstruction of airfield pavements in crisis situations and in military operations should enable to restore the operational availability of destroyed elements in the shortest possible time.

Basic Performance of Fibre Reinforced Asphalt Concrete with Reclaimed Asphalt Pavement Produced In Low Temperatures with Foamed Bitumen

During the reconstruction of road pavements, the reclaimed asphalt pavement (RAP), which is obtained through milling of the worn out existing asphalt, is commonly used for producing new base courses in cold recycling processes. Two of these techniques are most popular: one using mineral-cement-emulsion mixes and one utilizing mineral cement mixes with foamed bitumen. Additionally, some amounts of RAP can be incorporated into traditional hot mix asphalt. The demand for energy efficient and environmentally friendly solutions however, results in a need for development of new techniques that would result in cheaper and more reliable solutions with smaller carbon footprint. The reduction of processing temperatures with simultaneous incorporation of reclaimed material is the most efficient way of obtaining these objectives, but it often results in the overall decrease of bituminous mix quality. The paper presents the possibility of using RAP for producing asphalt concrete in warm mix asphalt (WMA) production process by the use of foamed bitumen modified with Fischer-Tropsch synthetic wax and polymer-basalt fibers. Additionally, a series of reference mixtures were produced to investigate the effects of the additives and of the warm process. The carried out analyses and tests shown that the experimental warm mix asphalt produced with RAP and foamed bitumen returned satisfactory performance. The introduction of synthetic F-T wax in the warm foam bitumen mixes resulted in a significantly improved compaction levels and moisture and frost resistance and the addition of polymer-basalt fibers has further improved the permanent deformation resistance of the mixes. All of the designed and tested mixes have fulfilled the requirements for binding course asphalt concrete with medium traffic loads.