scholarly journals Microwave Heating as an Innovative Road Maintenance Technology: Aging Effect on Binder and Feasibility Evaluation

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 316
Author(s):  
Aimin Sha ◽  
Baowen Lou ◽  
Diego Maria Barbieri ◽  
Inge Hoff

The microwave heating/healing technique is regarded as a green maintenance approach for asphalt pavements thanks to its promising environmental and economic benefits. However, the main concern about this technology is represented by the possible aging effect generated on bituminous binders. Currently, there is a significant lack of studies dealing with this topic. Based on these premises, the main purpose of this study is to appraise the feasibility of implementing microwave-based maintenance operations considering the associated aging effect. The assessment of fatigue life after cyclic microwave heating (MH) based on a linear amplitude sweep (LAS) test and the changes in the chemical groups detected through Fourier transform infrared (FTIR) spectroscopy document the aging phenomenon. The results indicate that the microwave aging degree on bituminous binder is nonlinear with MH cycles. The microwave radiation causes a distinct aging impact on binders during the first 10 cycles, then the values become constant. Furthermore, a feasibility analysis of MH technology is developed, encompassing four main multidisciplinary aspects: evaluation of microwave aging degree, working mechanism of MH equipment, safety assessment, and economic and ecological considerations. Despite the associated aging issue, the MH method is an efficient technology, considering its various advantages (i.e., rapidity of execution, uniform and non-pollutant treatment, and deep penetration). Meanwhile, the use of steel slag as a microwave absorber bolsters the sustainability of MH technology. This study provides a new perspective to evaluate the microwave heating technique in road engineering comprising the generated aging effect. Practice-oriented recommendations are also formulated regarding the safe implementation of MH technical operations.

Land ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 456
Author(s):  
Alexis Mooser ◽  
Giorgio Anfuso ◽  
Lluís Gómez-Pujol ◽  
Angela Rizzo ◽  
Allan T. Williams ◽  
...  

Coastal areas globally are facing a significant range of environmental stresses, enhanced by climate change-related processes and a continuous increase of human activities. The economic benefits of tourism are well-known for coastal regions, but, very often, conflicts arise between short-term benefits and long-term conservation goals. Among beach user preferences, five parameters of greater importance stand out from the rest, i.e., safety, facilities, water quality, litter and scenery; the latter is the main concern of this study. A coastal scenic evaluation was carried out in the Balearic Islands and focused on two major issues: coastal scenic beauty together with sensitivity to natural processes and human pressure. The archipelago is renowned as a top international coastal tourist destination that receives more than 13.5 million visitors (2019). Impressive landscape diversity makes the Balearics Islands an ideal field for this research. In total, 52 sites, respectively located in Ibiza (11), Formentera (5), Mallorca (18) and Menorca (18), were field-tested. In a first step, coastal scenic beauty was quantified using the coastal scenic evaluation system (CSES) method, based on the evaluation of 26 physical and human parameters, and using weighting matrices parameters and fuzzy logic mathematics. An evaluation index (“D”) was obtained for each site, allowing one to classify them in one of the five scenic classes established by the method. Twenty-nine sites were included in class I, corresponding to extremely attractive sites (CSES), which were mainly observed in Menorca. Several sound measures were proposed to maintain and/or enhance sites’ scenic value. In a second step, scenic sensitivity was evaluated using a novel methodological approach that makes possible the assessment of three different coastal scenic sensitivity indexes (CSSI), i.e., the natural sensitivity index NSI, the human sensitivity index HSI and the total sensitivity index TSI. Future climate change trends and projection of tourism development, studied at municipality scale, were considered as correction factors. All the islands showed places highly sensitive to environmental processes, while sensitivity to human pressure was essentially observed at Ibiza and Mallorca. Thereafter, sites were categorized into one of three sensitive groups established by the methodology. Results obtained are useful in pointing out very sensitive sceneries as well as limiting, preventing and/or anticipating future scenic degradation linked to natural and human issues.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Guozhen Zhao ◽  
Jianhua Liu ◽  
Lei Xu ◽  
Shenghui Guo

Abstract The effects of the conventional heating method and the microwave heating method on polyacrylonitrile-based fibres in the temperature range of 180–280 °C were investigated. Fourier transform infrared spectroscopy, X-ray wide-angle scattering, Raman spectroscopy, energy-dispersive spectrometer, scanning electron microscopy and bulk density were used to characterise the properties of the samples. Results show that the microwave heating method can shorten the pre-oxidation time, reduce pre-oxidation temperature and reduce the number of surface defects. The pre-oxidised fibres obtained by the microwave heating method exhibit not only good crystallite size but also a smooth surface. Atomic morphology and molecular arrangement are orderly inside the fibre. The FT-IR spectrum shows that the oxidation reaction occurs at 220 °C, and the CI value of PAN fibers stabilised by microwave heating is the larger than the fibers stabilised by conventional heating. XRD analysis shows that fibers stabilised by microwave heating have low stack domains. The SEM and Raman spectra indicate that hydrogen peroxide can improve the surface finish of the fibers and reduce defects. Microwave heating can reduce the pre-oxidation temperature by about 20 °C and shorten the heating time. The economic benefits of using this method are significantly improved.


2011 ◽  
Vol 189-193 ◽  
pp. 612-617
Author(s):  
Hong Wei Xing ◽  
Yue Long ◽  
Xiu Li ◽  
Gao Liang Li ◽  
Yu Zhu Zhang ◽  
...  

A gas quenching process to deal with steel slag and its characteristics of the new technology was briefly introduced. The grinding characteristics, mineral phases of gas quenching steel slag and the potential economic benefits of using it as cement mixing material was studied by compared to heat-stew steel slag. The results indicated that the specific surface areas (S) and grinding times (t) of the gas quenching steel slag showed a first order exponential decay relationship. With the extension of time, the specific surface areas of heat-stew steel slag was tending to balance earlier than that of gas quenching steel slag; The energy consumption of gas quenching steel slag was much lower than that of heat-stew steel slag. Gas quenching steel slag was comprised of C2S, C3S, a certain amount of (Ca2(Al, Fe)2O5)and RO phase, but the content of RO phase was relatively low, which increased the grindability of the quenching steel slag, so that the grindability of gas quenching steel slag was much better than that of heat-stew steel slag. Gas quenching steel slag prepared for cement addictives would bring great economic benefits.


2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Yongfeng Wei ◽  
Jinyang Huo ◽  
Zhenjun Wang ◽  
Jiangtao Gao

Emulsified asphalt needs to be cured for a certain age after demulsification to produce strength, which seriously affects the traffic opening time. In this work, microwave heating technology was applied for emulsified asphalt repair materials. Steel slag with high microwave activity was adopted to improve the performance of emulsified asphalt repair materials by microwave heating. Effects of steel slag sizes and contents on the heating rate, temperature distribution, and thermal performance of emulsified asphalt repair materials were analyzed by close microwave heating, open microwave heating, and repair simulation tests. Results show that the temperature of emulsified asphalt repair materials presents three different heating stages under microwave irradiation. The “critical point of phase transition” in the three stages is gradually advanced with the increase in steel slag content. The core temperature and maximum temperature of emulsified asphalt repair materials with different steel slag sizes are basically the same; however, the heat distribution of emulsified asphalt repair materials is significantly different. In contrast to conventional asphalt mixture, there exists a smaller temperature difference. The temperature of repairing materials can reach above 80°C. The interface area can form an embedded interface structure. Incorporation of steel slag and adoption of microwave heating are effective to improve the performance of emulsified asphalt repair materials.


2010 ◽  
Vol 150-151 ◽  
pp. 861-867 ◽  
Author(s):  
Yue Long ◽  
Yu Zhu Zhang ◽  
Hong Wei Xing ◽  
Jun Guo Li ◽  
Gao Liang Li ◽  
...  

According to a series of experimental studies such as the content of the f-CaO, the relative grindability index of the gas quenching steel slag, the properties of gas quenching steel slag cement and a detailed analysis of the potential economic benefits of steel slag cement. It was found that it has a huge economic benefits in preparing the cement with gas quenching steel slag.The results showed that the content of f-CaO in slag particles less than 2mm were no more than 2.7% and there exists a well proportional relation between it and the grain size; the grindability of gas quenching steel slag is much better than heat-stew steel slag; what's more,because of the high hydration activity of gas quenching steel slag, it can be produced the perfect steel slag cement with excellent hydration, stability and strength.


2019 ◽  
Vol 97 ◽  
pp. 06044
Author(s):  
Zhumabuke Ospanova ◽  
Nurgul Alibekova ◽  
Nursultan Satan

The paper presents energy-efficient technology with using microwaves to swell vermiculite. Replacement of traditional firing of vermiculite during exfoliation due to the use of microwave heating is promising, primarily due to lower energy costs.


2015 ◽  
Vol 768 ◽  
pp. 402-405 ◽  
Author(s):  
Can Hua Li ◽  
Xiao Dong Xiang ◽  
Xian Xian Qin

A new method to make SMA is developed by using SBS modified asphalt when the coarse aggregate steel slag and the fine basalt aggregate are selected respectively. The Mix Proportion is 1#(16-9.5mm, steel slag):2#(9.5-4.75mm, steel slag):3#(3-4.75mm, basalt):4#(3-0mm, basalt):5# (mineral powder)=38%:36%:8%:8%:10%.The optimal asphalt content (OAC) is 6.4%. The mass percentage of steel slag is reached 74%. The costs of this kind of high quality road material can be saved because the amount of asphalt is not increased. Based on Marshall Stability and Splitting Strength test, it is shown that the Marshall stability of SMA is 10.6 kN, dynamic stability is 7800, and tensile strength ratio is 89.2%. All above test values are superior to the standards in China's traffic regulations. The water permeability coefficient of SMA is 65, which means that SMA has an excellence Wear-Resistant performance. Therefore, SMA can increase the road useful life and reduce the road maintenance costs.


Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1306
Author(s):  
Xuefei Yang ◽  
Víctor López-Grimau ◽  
Mercedes Vilaseca ◽  
Martí Crespi

In this study, three different biological methods—a conventional activated sludge (CAS) system, membrane bioreactor (MBR), and moving bed biofilm reactor (MBBR)—were investigated to treat textile wastewater from a local industry. The results showed that technically, MBR was the most efficient technology, of which the chemical oxygen demand (COD), total suspended solids (TSS), and color removal efficiency were 91%, 99.4%, and 80%, respectively, with a hydraulic retention time (HRT) of 1.3 days. MBBR, on the other hand, had a similar COD removal performance compared with CAS (82% vs. 83%) with halved HRT (1 day vs. 2 days) and 73% of TSS removed, while CAS had 66%. Economically, MBBR was a more attractive option for an industrial-scale plant since it saved 68.4% of the capital expenditures (CAPEX) and had the same operational expenditures (OPEX) as MBR. The MBBR system also had lower environmental impacts compared with CAS and MBR processes in the life cycle assessment (LCA) study, since it reduced the consumption of electricity and decolorizing agent with respect to CAS. According to the results of economic and LCA analyses, the water treated by the MBBR system was reused to make new dyeings because water reuse in the textile industry, which is a large water consumer, could achieve environmental and economic benefits. The quality of new dyed fabrics was within the acceptable limits of the textile industry.


Author(s):  
Muhd Ikmal Mohd Jan ◽  
◽  
Noor Akhmazillah Mohd Fauzi ◽  

Recent years have seen the various studies conducted on the kelulut honey based on their physicochemical and nutritional properties. The main concern in production of kelulut honey in maintaining the quality especially when it is being treated. Previous studies have shown that conventional thermal processing that comprises two phases of heating which are liquefaction and pasteurization will minimize the quality of kelulut honey in terms of its physicochemical and nutritional properties due to its heat sensitivity material criteria. In addition, the reduction in quality of honey due to the unsteady components, breakdown of vitamins and damage of enzymes when it heated at more than 60℃ in thermal processing. Hence, a systematic review is carried out to identify a suitable heat treatment for kelulut honey as compared to conventional thermal processing in treating honey. The search strategy was established in three databases (Google Scholar, PubMed and ScienceDirect) with the search keywords “(“Honey”, “Kelulut”, “stingless bee”, “Trigona”, “Melipon”, “Microwave heating”, “Double boiling”, “HPP” or “High pressure processing” and “Ultrasound”)”. The data selection strategy was showed using PRISMA guidelines. A total of 311 journal papers were referred to complete this review, however, only 10 articles were highly considered specifically on the process of kelulut honey, where microwave heating, double boiling and high pressure processing (three articles respectively). Whereas, only two articles on analysis of ultrasound were found. From this literature review, it found that HPP provide higher benefit in improving physicochemical and nutritional properties of kelulut honey although it produces a lower change in colour if compared with other treatment. It can be concluded that HPP is the most potential in increasing the quality of kelulut honey followed by double boiling, ultrasound and microwave heating.


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