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Finite Element Analysis of Thiopave Modified Asphalt Pavement  [PDF]
Xiushan Wang, Junjie Wang, Yangjie Qiu
World Journal of Engineering and Technology (WJET) , 2019, DOI: 10.4236/wjet.2019.72B006
Abstract:
With the aim of studying the anti-rutting performance of Thiopave modified asphalt mixture applied to the upper layer of pavement, the strain-hardening creep model in ABAQUS finite element software was used to analyze the rutting under the condition of introducing temperature field. Compared with the calculation results of the rutting of ordinary asphalt pavement, it is found that Thiopave can improve the temperature sensitivity of asphalt mixture. With the increase of temperature, the rutting change of Thiopave modified asphalt pavement is smaller than that of ordinary asphalt. Thiopave also has a certain degree of improvement in the fatigue resistance of asphalt pavements, which can be applied to sections with high traffic volume in high temperature areas.
Disk Bimorph-Type Piezoelectric Energy Harvester  [PDF]
V. Tsaplev, R. Konovalov, K. Abbakumov
Journal of Power and Energy Engineering (JPEE) , 2015, DOI: 10.4236/jpee.2015.34010
Abstract:

The study of the experimental investigation of a disk-type piezoelectric energy harvester presented. The harvester contains disk bimorph piezoceramic element of the umbrella form and contains two disk PZT plates. The element is excited at the base point at its center. The element is supplied by a loading ring mass to decrease its resonance frequency. The dependences of the vibration displacement along the radii of the bimorph and the ring mass from the frequency of excitation are presented and the output voltage frequency response is also presented as well. The idle mode and the load duty are investigated. The value of the internal resistance of the harvester is obtained using the load characteristic. The piezoelectric specific power is estimated experimentally.

Investigating In Situ Properties of Recycled Asphalt Pavement with Foamed Asphalt as Base Stabilizer  [PDF]
Christina Plati,Andreas Loizos,Vasilis Papavasiliou,Antonis Kaltsounis
Advances in Civil Engineering , 2010, DOI: 10.1155/2010/565924
Abstract: The objective of the present study was to conduct a comprehensive field experiment for the in situ assessment of in-depth recycled asphalt pavement using foamed asphalt as a stabilization treatment for base works. For this purpose Nondestructive Testing (NDT) data collected using the Falling Weight Deflectometer (FWD) and Ground Penetrating Radar (GPR) along a foamed asphalt recycled pavement section was thoroughly analysed. Critical issues including the stabilized material curing and the contribution of the asphalt layers to the structural properties of the in-depth recycled pavement are discussed. In addition, recommendations concerning the improvement of the structural condition of the in-depth recycled pavement are developed based on this practical approach of investigation using NDT. 1. Introduction In-depth recycling is a method implemented worldwide for the rehabilitation of damaged road pavements. One of the major benefits of the method is that the material of a distressed road pavement is simultaneously recycled in-place and mixed with a stabilizing agent, enabling the road pavement to be strengthened without the need to import expensive aggregate. Other benefits include a short construction period, significantly reduced road closures, and improvements relating to safety. These advantages contribute to significantly lower unit costs for road rehabilitation, in comparison with other rehabilitation methods [1]. In addition, environmental issues related to the reuse of road materials increase the advantages of this technology. For the in-depth recycling method, which is often referred to in international literature as cold in-place recycling [2], several types of stabilizers are used for the treatment of the in-place recycled material. The present investigation focuses on the use of foamed asphalt for such stabilization purposes. It is worthwhile to note that this technique has gained popularity in recent years. However, the in-depth asphalt pavement recycling using foamed asphalt as a stabilization treatment for base works requires a certain time period necessary to allow the newly produced foamed asphalt mixture to cure, as is the case for most stabilizing agents, and to build up enough internal cohesion before being covered by a wearing course. Studies have shown that such recycled mixes do not develop their full strength after compaction until a large percentage of the mixing moisture is lost. This process termed “curing” is a process whereby the in-depth recycled and stabilized mix gradually gains strength over time accompanied by a reduction
Electroaeroelastic Modeling and Analysis for Flow Energy Piezoelectric Harvester  [PDF]
Zhang Jiantao, Wu Song, Shu Chang, Li Chaodong
- , 2017, DOI: 10.16356/j.1005-1120.2017.01.009
Abstract: An electroaeroelastic model for wind energy harvesting using piezoelectric generators is presented. The flow field is mapped in detail. The force which the fluid flow exerts on the generator is formulated. The output voltage levels generated from the mechanical strain within the piezoelectric elements are determined. An analytical model is developed with consideration of the interactions between the fluid, solid and electric. Various analytical results are obtained, such as flow velocity contour and pressure contour for the flow, moving trajectories, stress contour and output voltage of the harvester. A prototype is fabricated and tested. The simulation result is close to the experimental result. The model developed in this paper can predict the performance and behavior of different energy harvesters. And it also can be used as a design tool for optimizing the performance of the harvester.
Pavement performance and application of anion rubber-modified asphalt
Wei Hong,QingShan Li,GuoQuan Guan,Jun Liu,Jing Sun,GuangZhong Xing
Chinese Science Bulletin , 2012, DOI: 10.1007/s11434-012-5065-7
Abstract: We have used a unique process to develop the first successful anion rubber modified asphalt mixture. Rubber and asphalt are used in equal proportions in the mix. Compared with conventional asphalt, the anion rubber modified asphalt show better pavement performance, and fully met the relevant specifications. The dynamic stability and failure strain indicators are better than those of SBS modified asphalt. Compared with traditional rubber modified asphalt, the amount of waste tires incorporated into this new rubber modified asphalt is much greater; the new asphalt also improved the air quality near the road, thus providing great economic and social benefits.
Performance of Recycled Asphalt Pavement as Coarse Aggregate in Concrete  [PDF]
Fidelis O. OKAFOR
Leonardo Electronic Journal of Practices and Technologies , 2010,
Abstract: Recycled asphalt pavement (RAP) is the reclaimed and reprocessed pavement material containing asphalt and aggregate. Most RAP is recycled back into pavements, and as a result there is a general lack of data pertaining to the mechanical properties for RAP in other possible applications such as Portland cement concrete. In the present study, some mechanical properties of Portland cement concrete containing RAP as coarse aggregate were investigated in the laboratory. Six concrete mixes of widely differing water/cement ratios and mix proportions were made using RAP as coarse aggregate. The properties tested include the physical properties of the RAP aggregate, the compressive and flexural strengths of the concrete. These properties were compared with those of similar concretes made with natural gravel aggregate. Results of the tests suggest that the strength of concrete made from RAP is dependent on the bond strength of the asphalt-mortar (asphalt binder-sand-filler matrix) coatings on the aggregates and may not produce concrete with compressive strength above 25 MPa. However, for middle and low strength concrete, the material was found to compare favorably with natural gravel aggregate.
Power Analysis for Piezoelectric Energy Harvester  [PDF]
Wahied G. Ali, Sutrisno W. Ibrahim
Energy and Power Engineering (EPE) , 2012, DOI: 10.4236/epe.2012.46063
Abstract: Piezoelectric energy harvesting technology is used to design battery less microelectronic devices such as wireless sensor nodes. This paper investigates the necessary conditions to enhance the extracted AC electrical power from exciting vibrations energy using piezoelectric materials. The effect of tip masses and their mounting positions are investigated to enhance the system performance. The optimal resistive load is estimated to maximize the power output. Different capacitive loads are tested to store the output energy. The experimental results validated the theoretical analysis and highlighted remarks in the paper.
Warm-Mix Asphalt and Pavement Sustainability: A Review  [PDF]
Kenneth A. Tutu, Yaw A. Tuffour
Open Journal of Civil Engineering (OJCE) , 2016, DOI: 10.4236/ojce.2016.62008
Abstract: Within the past two decades or so, the asphalt paving industry has responded positively to increasing global concerns over shrinking natural resource reserves and worsening environmental conditions through the development and deployment of warm-mix asphalt technologies. Such technologies make it possible to produce and place asphalt concrete at reduced temperatures compared to conventional hot-mix methods. Several studies have reported on the potential of warm-mix asphalt with regard to improved pavement performance, efficiency and environmental stewardship. This paper reviews several of those studies in the context of pavement sustainability. Overall, warm-mix asphalt provides substantial sustainability benefits similar to or, in some cases, better than conventional hot-mix asphalt. Sustainability benefits include lower energy use, reduced emissions, and potential for increased reclaimed asphalt pavement usage. Growth in utilization of warm-mix asphalt worldwide may, in the not-too-distant future, make the material the standard for asphalt paving. Regardless, there are concerns over some aspects of warm-mix asphalt such as lower resistance to fatigue cracking, rutting and potential water-susceptibility problems, particularly with mixes prepared with water-based technologies, which require further research to address.
Design Methodologies of Asphalt Pavement Used in China and Mozambique  [PDF]
Jose Francisco Rufino Diogo,Ammar Abbas Mohammed Shubber,Mu Han Lin
Journal of Applied Sciences , 2007,
Abstract: This study discusses and compares Asphalt Concrete (AC) pavement design methodologies used in China and Mozambique (based on South African Transportation and Communication Commission (SATCC) methodologies). The SATCC design methodologies use California Bearing Ratio (CBR) and catalogues methods. The South African catalogues are basically used for roads with traffic less than 30 million ESAs. The design catalogues method give small thickness than CBR and Chinese methods. The Chinese and the South African design methods give nearly the same thickness; this study concludes that these methods can be used in both countries; China and Mozambique. The results also show that the strong point of Chinese method is verifying the tensile stress and allowable displacement on the pavement calculated from computer program APDS.
Modeling and Analysis of a Random Excited Double-Clamped Piezoelectric Energy Harvester
Modeling and Analysis of a Random Excited Double-Clamped Piezoelectric Energy Harvester
 [PDF]

Xiaoya Zhou,Shiqiao Gao,Haipeng Liu
- , 2017, DOI: 10.15918/j.jbit1004-0579.201726.0303
Abstract: A double-clamped piezoelectric energy harvester subjected to random excitation is presented, for which corresponding analytical model is established to predict its output characteristics. With the presented theoretical natural frequency and equivalent stiffness of vibrator, the closed-form expressions of mean power and voltage acquired from the double-clamped piezoelectric energy harvester under random excitation are derived. Finally theoretical analysis is conducted for the output performance of the double-clamped energy harvester with the change of spectrum density (SD) of acceleration, load resistance, piezoelectric coefficient and natural frequency value, which is found to closely agree with Monte Carlo simulation and experimental results.
A double-clamped piezoelectric energy harvester subjected to random excitation is presented, for which corresponding analytical model is established to predict its output characteristics. With the presented theoretical natural frequency and equivalent stiffness of vibrator, the closed-form expressions of mean power and voltage acquired from the double-clamped piezoelectric energy harvester under random excitation are derived. Finally theoretical analysis is conducted for the output performance of the double-clamped energy harvester with the change of spectrum density (SD) of acceleration, load resistance, piezoelectric coefficient and natural frequency value, which is found to closely agree with Monte Carlo simulation and experimental results.
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