Papers by Keyword: Pavement Engineering

Abstract: This review paper focuses on the major factors of deterioration, specifically rutting, stripping, and moisture effects, which are key factors affecting road pavements globally. Stressing the need to tackle these distresses, the study aims to improve the performance of asphaltic courses via advancing bio-based reinforcement materials, especially sisal fiber. The paper tries to analyze the mechanism of rutting in asphalt mixtures with a special reference to sisal fibers as an agent to increase resistance to permanent deformation. However, fiber reinforcement with the asphalt mixtures are also briefly described in the subject with the favorable effects of tensile strength, fatigue strength and crack propagation strength. The review further focuses on the ability of fiber reinforcement to enhance pavement service life, address pavement deterioration issues, and improving the service life of road pavements.

Abstract: In order to deeply reveal the high temperature stability of asphalt mixture, rutting test was implemented to evaluate the high temperature stability of asphalt mixture, and the evaluation index is dynamic stability. The effect of asphalt type, degree of compaction, gradation type and nominal maximum aggregate size on rutting test results was studied respectively. The results showed that: modified asphalt can improve the high temperature stability of asphalt mixture effectively; the anti-rutting performance of asphalt mixture reduces gradually with decrease of the degree of compaction; the anti-rutting performance of SAC-16 is greater than that of AC-16; and the anti-rutting performance of asphalt mixture is improved with increase of the nominal size of aggregate.

Abstract: To research the grading applicability of Lucobit modifier and make it adapt to China's basic national conditions very well, the gradations of SUP-20 was selected to research mix design and pavement performance in the text. First, the mix design of SUP-20 without Lucobit is researched. Then the performance of SUP-20 is verified including the high temperature, low temperature and water stability performance of common asphalt mixture. At last the performance comparison between SUP-20 asphalt mixture with 7% Lucobit and without is carried out. Results show that the performance of SUP-20 asphalt mixture with 7% Lucobit and without can all meet the requirement. Compared with the performance of SUP-20 asphalt mixture without Lucobit, the low temperature and water stability performance with Lucobit have a little improvement and the high temperature performance improves a lot. So Lucobit modifier can greatly improve the high temperature performance of SUP-20 asphalt mixture.

Abstract: The aged crumb rubber modified asphalt (abbreviated as CRMA) was recycled with two methods which were adding fresh CRMA binder and adding recycling agent to investigate the recycling feasibility of aged CRMA binder. The performance of recycled CRMA binder was evaluated systematically with a variety of indices, including penetration, softening point, ductility and viscosity. The results indicate that the performance of recycled CRMA binder has good correlation with the content of the fresh CRMA binder or recycling agent. The performance of recycled CRMA binder mixing with the fresh CRMA binder or recycling agent with the optimistic content is improved and can meet the technical requirements. According to the relevant technical standards in “Guidelines for design and construction of asphalt rubber and mixtures in Beijing”, the index of recycled CRMA binder can reach the standard when the content of fresh CRMA binder is 70% or content of recycling agent is 6%. The experimental results show that the recycling of the aged CRMA asphalt is feasible.

Abstract: With the increasing of the large-size and overload of highway transport vehicles, the riding quality and the service life of pavement engineering are facing with a rigorous challenge. According to maintenance experiences from various countries in the world, adopting a reliable pavement preventive maintenance (PPM) measure is an effective method to keep the pavement with a good service level with the less expenditure of capital. The selection plan of the optimal measure is one of the critical aspects of the PPM technology. Whether a PPM measure is suitable or not is closely related to the PPM technical features, the pavement conditions and the traffic service levels. The purpose of the paper was to put forward the principle, method and procedure of the optimal PPM measure selection in terms of the specific features of asphalt pavements based on the decision matrix analysis and the equivalent annual cost method. The analysis results of a project level case demonstrates that the micro surfacing technology is the most suitable PPM measure to match the practical pavement conditions of the Puxing Road.

Abstract: California bearing ratio (CBR) test was carried out, CBR changing laws of different graded crushed rocks were analyzed, an aggregate gradation on the base of port was put forward, and its performances were verified through laboratory test. Test result shows that the main skeleton structure composed of the aggregate with diameter 19mm-4.75 mm has interlocked force, and the optimal mass fraction is 90%~65%. The aggregates with diameter 4.75mm-0.075mm have the effects of filling the void of main skeleton structure, whose optimal mass fraction is 10%-35%.And the optimal mass fraction of the aggregate with diameter 19mm-9.5 mm is 25%.When the optimum proportion of coarse aggregate to middle aggregate is 25:40, the CBR value of coarse-middle-fine combined aggregate reaches the highest point, and is more than 158.97%, and the ratio reached 377%. On this basis, the optimal aggregate gradation of graded broken stone is reference on design and construction of graded crushed rock on the base of port.

Abstract: To analyze the dynamic response of the pavement structure under moving vehicle loading is always a hot point in pavement engineering. In this paper, the moving vehicle has been simplified as spring-dashpot components and the pavement structure has also been discrete using three-dimension finite element model. Based on Newton iteration and central difference integration algorithm, the static and dynamic coupling reactions between pavement structure and vehicle have also been considered using finite element platform ABAQUS. The numerical results and analytic results can fit very well in static analysis, meanwhile the numerical results and experiment results can fit very well in dynamic analysis. Based on preceding verified numerical model, a few interesting phenomenon have been discovered. The pavement dynamic vertical displacement in upper layer is much higher than the situation in static analysis, because the vertical displacement is superimposed during the dynamic response analysis. Furthermore the vertical fluctuation of the vehicle's bar center exists even the vehicle moving in the initial even pavement, and the inertial forces is the most important reason to induce this behavior. In the last, this paper has proposed a more accurate, fast and concrete evidence to explain the reason that the dynamic response has obvious relationship with the diseases in pavement layer.

Abstract: To study the properties of warm mix flame retardant asphalt mixture, a series tests were put forward, including Marshall Combustion experiments, rut specimen combustion experiment and texture depth experiment. With less mass loss, the warm mix retardant asphalt mixture has a better Marshall Stability, residual stability and freeze-thaw splitting strength ratio after combustion. The composite flame retardant can slow down and stop the burning of asphalt, reduce asphalt aging degree during burning process. The burning amount of warm mix flame retardant asphalt mixture is less than the ordinary hot mix asphalt concrete. To sum up, the warm mix flame retardant asphalt mixture has a good comprehensive performance.

Abstract: In the maintenance for the pavement, there is no method to adjust and rebuild all the design elevation which is in using on the pavement because of the as build structure that are located in the periphery. In order to coordinate the design situation which is considered or no considered in the site, this research develops the “Virtual Reality Digital Pavement System (VRDPS)”. The user can see the difference in the pavement quality and the influence of the pavement linear in different view by the Intuitive method. It can also provide the analysis for the construction cost and pavement linear in the different design.

Abstract: This study analyzes key success factors of bidding results and provides the optimal bidding strategy for the pavement engineering. According to Public construction bidding management system data of Public Construction Commission of Executive Yuan, we found that the optimal bidding strategies in the most studies only focused on bidding prices and winning bid amounts. However, public constructions are usually on a large scale with great investments, it is critical to control budgets under quality and duration considerations. In addition, it is complicated for bidders to implement the optimal bidding strategy under multiple bidding factors. Hence, this study applies statistical analysis to find key success factors of bidding data in Taoyuan pavement engineering from 2008 to 2012 for evaluating the optimal bidding strategy with the multi-criteria decision-making method. Our research results show that bidders can increase the probability of winning bids and enables to allocate their resources with accurate bidding price forecast. In particular, the differences between the award amounts and base prices after applying the optimal bidding strategy are also provided.