Industrial waste management constitutes a major challenge for sustainable development. This study aims to transform hardened cement waste stored in cement warehouses and in real estate construction sites into paving s...Industrial waste management constitutes a major challenge for sustainable development. This study aims to transform hardened cement waste stored in cement warehouses and in real estate construction sites into paving stones. This innovative solution will contribute to the protection of the environment and the reduction of inert industrial waste. To do this, paving stones based on hardened cement have been developed and characterized. The raw materials were subjected to physical and mechanical characterization tests. The hardened cement aggregates previously crushed with the 5/15 granular class were used as substitutes to replace the natural 5/15 aggregates in the hardened paving stones at contents ranging from 0 to 100%. The mechanical characterization results on the raw material showed that the hardened cement aggregate is made from lightweight aggregates. On the prepared mortar, in the fresh state, the Abrams cone slump test showed an increase in the quantity of waste water with the increase in the content of hardened cement aggregate. In the hardened state, physical (porosity, absorption and dry density) and mechanical (compression, splitting traction, 3-point bending traction and wear) characterization tests were carried out at periods of 7, 14 and 28 days of maturation in water on the cobblestones. These results show that the substitution of natural aggregates by hardened cement aggregates in increasingly large proportions leads to an improvement in compressive, flexural, splitting and wear resistance. In addition, the incorporation of hardened cement aggregate considerably slows down the mechanical degradation of the paving stones. They can, therefore, be used in road and interior or exterior floor coverings.展开更多
Concrete pavement often experiences accelerated deterioration due to water and chemical ingress through micro-cracks and surface voids.Particularly,the ingress of aggressive agents into the concrete matrix results in ...Concrete pavement often experiences accelerated deterioration due to water and chemical ingress through micro-cracks and surface voids.Particularly,the ingress of aggressive agents into the concrete matrix results in irreversible changes and deterioration on its endurance.Numerous studies unveiled that hydrophobic surface protection could be an inexpensive and effective way of enhancing the durability of concrete.This research work aims to assess the feasibility of bio-cement posttreatment for facilitating hydrophobic surface protection,thus enhancing the performance and durability of concrete blocks.Enzyme induced carbonate precipitation(EICP)is one of the promising bio-cement methods.Concrete blocks casted in four different grades were subjected to EICP treatment with different treatment schemes and recipes of cementation media.The treated blocks were tested for water absorption,ultrasonic pulse velocity(UPV)measurements,unconfined compressive strength(UCS),thermal performance,and scanning electron microscopy(SEM).The results indicated that the concrete blocks subjected to EICP posttreatment showed over a 55%reduction in water absorption,a 15%higher UCS and a 6.7%higher UPV when compared with control blocks.The SEM analysis suggested that the EICP posttreatment could enhance the durability of concrete paving blocks by enabling a layer of calcite on the surface and by plugging the transport pore channels of the concrete.Although most of the posttreatment strategies investigated herein were found to be operative,a better response was seen in the posttreatment by spraying scheme with 0.5 mol/L cementation media(CM).With the successful demonstration,the EICP treatment prior to the use of concrete blocks can be recommended to the pavement construction industry.展开更多
Many industrial sectors exploit fossil sources to develop useful and necessary materials for our needs,such as bituminous paving materials.Bitumen,a key component of asphalt mixtures,is derived from oil refining and i...Many industrial sectors exploit fossil sources to develop useful and necessary materials for our needs,such as bituminous paving materials.Bitumen,a key component of asphalt mixtures,is derived from oil refining and its properties are influenced by the crude oil source and refining process,resulting in a significant carbon footprint.With growing awareness of resource depletion and environmental concerns,pavement researchers are exploring sustainable alternatives to reduce dependence on fossil sources.This includes a rising trend in using renewable materials like biomasses to produce bio-based binders as substitutes for bitumen,aiming for a more sustainable approach.Biomasses,including vegetal and animal wastes,and waste cooking oils,as substitutes for crude oil in the production of bio-binders.Through thermochemical conversion(TCC),such as pyrolysis,biomasses can be converted into bio-char and bio-oils,which can replace fossil-based components in binders.Researchers have utilized these bio-products to reduce the dependency on fossil fuels in binders.However,there are no set minimum requirements for bio-components in bio-based binders.As the percentage of replaced bitumen increases,various types of binders are produced,including modified bitumen,extended bitumen,and alternative binders,where the fossil replacement is gradual.Overall rheological tests on bio-binders,reveal that those containing biochar exhibit increased viscosity,stiffness,rutting resistance,and sometimes antioxidant properties.Conversely,bio-binders with bio-oils as bitumen substitutes show poorer performance at high temperatures but improved behavior at low temperatures.These results suggest that bio-binders could provide versatile solutions for various climatic and loading conditions in road construction.However,the development of pavement mixtures based on bio-binders has not been studied in depth and requires further attention to unlock its full potential.As sustainability considerations,including life cycle assessments(LCA)and life cycle cost analyses(LCC),are crucial aspects for future studies.It is essential not only to collect data on the performance characteristics of bio-binders but also to understand their environmental impact and recyclability.In-depth evaluations using methods such as LCA and LCC will provide valuable insights into the overall sustainability and long-term viability of these products.展开更多
Tactile paving is a professional road facility to ensure the safe travel of people with visual impairment.However,there are many problems with tactile paving travel in practice.For one,some tactile paving is seriously...Tactile paving is a professional road facility to ensure the safe travel of people with visual impairment.However,there are many problems with tactile paving travel in practice.For one,some tactile paving is seriously damaged,and the other is the accumulation of obstacles.How to help visually impaired people recognize and locate obstacles in tactile paving is a problem worth studying.In this paper,image recognition technology is used to recognize the tactile paving pictures with obstacles,and an attention mechanism is used to optimize samples to improve recognition accuracy.展开更多
The important parameters that influence the mechanical property of the pavinglayer on an orthotropic steel bridge deck are the paving layer thickness and modulus of the asphaltconcrete surfacing. Three important indic...The important parameters that influence the mechanical property of the pavinglayer on an orthotropic steel bridge deck are the paving layer thickness and modulus of the asphaltconcrete surfacing. Three important indices that control the typical failures of the paving layerare the maximum tensile stress of paving layer, the maximum shear stress between the steel deck andthe paving layer, and the maximum deflection on the paving surface. In this paper, the analyticalmodel of paving systems on orthotropic steel bridge deck is established, and the finite elementmethod is adopted to study the stress and strain of paving system. With the variation of asphaltconcrete modulus in high or low temperature season, the influences of paving layer thickness onthree control indices are researched. The results provide a theoretical basis for the determinationof thickness of the paving layer on the steel bridge deck.展开更多
Many specifications of paving asphalts are closely related to their colloidal stability, which is, however, determined by their exact chemical compositions. The Yumen vacuum residue (YVR), the bottoms of a paraffinic...Many specifications of paving asphalts are closely related to their colloidal stability, which is, however, determined by their exact chemical compositions. The Yumen vacuum residue (YVR), the bottoms of a paraffinic crude oil is unfit for the production of highway paving asphalts directly, Neither are the de-oiled asphalts of the YVR. In this research a blending method and an optimal process of solvent de-asphalts are adopted to investigate the feasibility of formulating highway-paving asphalts from YVR. Results show that highway paving asphalts are formulated by blending solvent de-oiled asphalts with one or more of the materials including YVR, decanted oil from FCC process, and furfural extracts from lubricating base stocks. Further investigations indicate that adding oil decanted from FCC process to the solvent de-asphalting process can increase the de-asphalted oil production, improve the de-oiled asphalts quality, and thus optimize the refinery processes. The methodology of this research can be extended even to refineries processing non-paraffinic crude oils.展开更多
The paving segregation of asphalt mixture was closely related to the structure size and using parameters for the screw distributor of paver,and the paving uniformity of the mixture was determined by the screw blade di...The paving segregation of asphalt mixture was closely related to the structure size and using parameters for the screw distributor of paver,and the paving uniformity of the mixture was determined by the screw blade diameter,pitch,and the position of the mixture in the screw distributor.Through researching the kinematics of the mixture in the screw distributor,the mathematical model was established,and the mathematical model was related with structural parameters,used parameters and material parameters.Through the mathematical model,the various parameters on the screw distributor job performance were analyzed,and the unstable area,meta-stable area and stable area were determined.In the project,the full-scale test in actual project was conducted by using the AC25 mixture.By changing the using parameters compare the paving operations,the results show that,the reasonable parameter will greatly improve the uniformity of paving,and the surface proportion of structural depth of mixture decrease from the 2.13 to 1.60.展开更多
With the rapid development of modern industry,high-grade paving asphalt is massively required to meet the demands for modern transportation.As one of additives,natural asphalt is indispensable since it can improve the...With the rapid development of modern industry,high-grade paving asphalt is massively required to meet the demands for modern transportation.As one of additives,natural asphalt is indispensable since it can improve the performance of paving asphalt in all aspects.However,the application of non-renewable natural asphalt is increasingly restricted by its limited reserves.It is imperative to find alternative approaches to produce high-grade paving asphalt.Fluid catalytic cracking(FCC)slurry oil is an ideal soft component for producing paving asphalt due to its high content of aromatics and resins.However,its bad ageing resistance limits its application to only low-grade paving asphalt.In the present work,a novel approach for producing high-grade paving asphalt was investigated using chemically modified FCC slurry oil and deoiled asphalt(DOA).The FT-IR and NMR results showed that dehydrogenation and condensation reaction occurred during the ageing process.From a series of aliphatic alcohols and aldehydes,propanal was selected as a proper modifier to improve the ageing resistance of FCC slurry oil.The propanalmodified slurry oil possessed more substituted aromatic units and less aromatic hydrogen atoms than other modified slurry oils,thus showing better ageing resistance.With the increase of length of aliphatic chains in modifier,the modified slurry oil contained more and longer alkyl substituent group on aromatics.Compared with the cross-linked oil(slurry oil modified by cross-linking agent),modified slurry oil possessed similar ageing resistance but higher flowing ability.Also,the effect of operation conditions on the kinematic viscosity of modified slurry oil were investigated.Blended with modified slurry oil,the penetration ratio of asphalt product increased from 53.7 to 66.2,which met the standard of 70#paving asphalt.Both the microscopic observations and FT-IR results indicated that modification process effectively reduced the oxidation degree of asphalt product,thus increasing the ageing resistance.Consequently,with aid of this process,high-grade paving asphalt was readily produced from low value oil from downstream products of refinery,instead of the depleting natural asphalt.展开更多
In order to enlarge the use of coal tar pitch(CTP) in paving road,CTP and 60th paving pitch (PP) were extracted by n-heptane,toluene and ethanol step by step in a Soxhlet apparatus.The three fractions of CTP and PP we...In order to enlarge the use of coal tar pitch(CTP) in paving road,CTP and 60th paving pitch (PP) were extracted by n-heptane,toluene and ethanol step by step in a Soxhlet apparatus.The three fractions of CTP and PP were detected using UV-absorption(UV-A),elemental analyses(EA) and nuclear magnetic resonance(NMR) firstly as a whole unit after quality characterization of physical nature of CTP and PP were finished.The CTP had more saturate aliphatic and residue compounds dissolved in ethanol.On the other hand there were more continental type structures of aromatic ring than that of PP.There was almost no residue in PP after extracted by ethanol.The results explained why CTP was crisp in cold winter and was soften in summer.The following research will focus on how to change the chemical construction of CTP into the relative similar structures with those of PP through adding polymer.展开更多
The China Council for the Promotion of International Trade (CCPIT) held the Second Session of the Second Council of its National Congress in the latter half of July. Attending the session were officials in charge of f...The China Council for the Promotion of International Trade (CCPIT) held the Second Session of the Second Council of its National Congress in the latter half of July. Attending the session were officials in charge of foreign economic relations and trade from related Chinese ministries, provinces, municipalities and autonomous regions, chairmen of 46 local and 14 industrial sub-councils throughout展开更多
Neurodegenerative diseases are a leading cause of disability worldwide,and despite significant resources put toward the discovery of potential therapeutic targets,there are currently no effective treatments.The rise o...Neurodegenerative diseases are a leading cause of disability worldwide,and despite significant resources put toward the discovery of potential therapeutic targets,there are currently no effective treatments.The rise of methods to derive and propagate stem cells in vitro offered展开更多
The construction method of continuous paving of the upper and lower base of the water stable macadam base can improve the construction efficiency,overcome the quality problems of the traditional layered paving of the ...The construction method of continuous paving of the upper and lower base of the water stable macadam base can improve the construction efficiency,overcome the quality problems of the traditional layered paving of the upper and lower base,such as untimely curing,slow construction,poor interlayer bonding,contraction joint and interlayer,so as to ensure the construction quality of the water stable macadam.It is also the promotion and application of new technology.展开更多
This year is the 25th anniversary of the normalization of Sino-Japanese Rela-tions. In the past 25 years, relations between the two countries were by and largegood, but problems never ceased to occur. Some problems we...This year is the 25th anniversary of the normalization of Sino-Japanese Rela-tions. In the past 25 years, relations between the two countries were by and largegood, but problems never ceased to occur. Some problems were considered pre-dictable but others were quite weird, to the Chinese part at least. To improve thebilateral relationship in the 21st Century, both Beijing and Tokyo need to展开更多
In the construction of asphalt mixture pavement,there are many paving construction procedures,high requirements for machinery and personnel,unreasonable technology and so on.In this paper,the millimeter-scale 3D autom...In the construction of asphalt mixture pavement,there are many paving construction procedures,high requirements for machinery and personnel,unreasonable technology and so on.In this paper,the millimeter-scale 3D automatic paving control technology of asphalt mixture pavement is studied with an engineering example.From the analysis of the test results in the later stage of construction,it can be seen that the technology has achieved the goal of high precision paving,and the successful application of the technology provides valuable reference experience for similar asphalt concrete pavement construction in the future.展开更多
Tremolite group minerals could be present in the aggregate used as filler in the mix asphalt floor in the road surfaces and are subject to wear for vehicular traffic and materials ageing.Dust produced by the degradati...Tremolite group minerals could be present in the aggregate used as filler in the mix asphalt floor in the road surfaces and are subject to wear for vehicular traffic and materials ageing.Dust produced by the degradation of asphalt surfaces can disperse tremolite group minerals present in road paving causing exposure by asbestos fiber to an increasing number of people and animals.In recent years,attention has been focused on naturally occurring asbestos(NOA)as the greatest frequency of lung cancer has been observed in environments characterized by rocks and soils rich in Tremolite that characterize asbestos minerals.Asphalt samples object of this study were collected in a motorway segment of the Lombardia Region(north of Italy)for an exposure assessment research on road paving workers.The evaluation was performed using a metrological approach based on petrographic and mineralogical analyses in order to reduce the epidemiologic risks and to define the best treatment strategies on waste management with sustainable costs in fulfilment of Council Directive 67/548/EEC(1967)and EC Regulation 1272/2008(2008)(Paglietti et al.,2016).The fibers are generally not broken down to other compounds in the environment,but asbestos hazard could be related to the occurrence of tremolite fiber in road paving arises when natural weathering processes(e.g.,erosion)or human activities(e.g.,continuous passage of motorized vehicles)separate and break down the fibers,which could be lost into the environment as airborne and easily penetrate into the human respiratory tract(Punturo et al.,2019).Despite this,this work is not an epidemiological risk analysis but obtained data could be useful to other specialists to define the exposure risks.展开更多
The improvement of road surface engineering construction quality is helpful to create safe and comfortable travel conditions for people and prevent traffic accidents. With the acceleration of highway construction in o...The improvement of road surface engineering construction quality is helpful to create safe and comfortable travel conditions for people and prevent traffic accidents. With the acceleration of highway construction in our country, the standard of pavement construction is also improving. Only by strictly following the national and industry standards can the service life of the pavement be prolonged and the subsequent maintenance and management work be guaranteed. Especially in asphalt paving, temperature, humidity and geological conditions will have different degrees of influence, which brings great difficulty to the construction. Performance parameters such as compactness and cohesiveness of asphalt mixture also determine the overall paving quality. In the construction, the effect of various factors should be considered, and a practical construction organization scheme should be prepared according to the construction requirements and actual conditions of highway pavement engineering. In addition, ensure that the paving technology meets the standard requirements, strengthen the construction standardization and reduce the probability of pavement diseases.展开更多
The stability of roads in cities directly affects the safety of traffic and transportation.In the process of pavement laying,relevant personnel should use permeable paving materials in the process of construction.Base...The stability of roads in cities directly affects the safety of traffic and transportation.In the process of pavement laying,relevant personnel should use permeable paving materials in the process of construction.Based on the analysis of road drainage requirements,traditional paving materials have relatively poor water permeability,which leads to ponding problems during road use[1].Within this frame of reference,beginning with the characteristics of permeable paving materials,this paper makes an in-depth exploration on practical application measures.展开更多
China’s largest private equity fund focusing on African investments boosts its footprint on the continent THE China-Africa Development Fund (CADFund),which has traditionally kept a low profile,has often been seen in ...China’s largest private equity fund focusing on African investments boosts its footprint on the continent THE China-Africa Development Fund (CADFund),which has traditionally kept a low profile,has often been seen in the public spotlight over the past year. The fund and cement producer,Jidong Development Group,decided to invest approximately $220 million to set up a cement plant展开更多
No stranger could detect anything unnatural to see the 14-year-old Zhang Lizheng burst into the house with the greeting remark, "Mom, I’m back!" He’s just returned from school. "You’re the last to co...No stranger could detect anything unnatural to see the 14-year-old Zhang Lizheng burst into the house with the greeting remark, "Mom, I’m back!" He’s just returned from school. "You’re the last to come back today," says the "Mom" indulgently, taking off the boy’s jacket and hanging it on the clothes rack next to the door. "Wash your hands and dinner is ready." On the round dinner table lie several dishes and six sets of bowls and chopsticks. "You’ll also have your favorite scrambled eggs and tomatoes tonight," smiles the lady in her late 20s, who looks too young to be a mother of four boys.展开更多
THE Ninth BRICS Summit will be held in China＇s Xiamen City in early September. The last time China hosted the BRICS Summit was in 2011, when South Africa was accepted as a full member. South Africa＇s accession not o...THE Ninth BRICS Summit will be held in China＇s Xiamen City in early September. The last time China hosted the BRICS Summit was in 2011, when South Africa was accepted as a full member. South Africa＇s accession not only strengthens the BRICS countries＇ direct links with the Afri- can continent, but also broadens BRICS in terms of economic aggregates, population and area. More importantly, the move has greatly enhanced the representative- ness of the mechanisms as its coverage expanded from Asia, Europe and America to Africa, making it an economic coopera- tion mechanism for emerging economies covering the whole world,展开更多
文摘Industrial waste management constitutes a major challenge for sustainable development. This study aims to transform hardened cement waste stored in cement warehouses and in real estate construction sites into paving stones. This innovative solution will contribute to the protection of the environment and the reduction of inert industrial waste. To do this, paving stones based on hardened cement have been developed and characterized. The raw materials were subjected to physical and mechanical characterization tests. The hardened cement aggregates previously crushed with the 5/15 granular class were used as substitutes to replace the natural 5/15 aggregates in the hardened paving stones at contents ranging from 0 to 100%. The mechanical characterization results on the raw material showed that the hardened cement aggregate is made from lightweight aggregates. On the prepared mortar, in the fresh state, the Abrams cone slump test showed an increase in the quantity of waste water with the increase in the content of hardened cement aggregate. In the hardened state, physical (porosity, absorption and dry density) and mechanical (compression, splitting traction, 3-point bending traction and wear) characterization tests were carried out at periods of 7, 14 and 28 days of maturation in water on the cobblestones. These results show that the substitution of natural aggregates by hardened cement aggregates in increasingly large proportions leads to an improvement in compressive, flexural, splitting and wear resistance. In addition, the incorporation of hardened cement aggregate considerably slows down the mechanical degradation of the paving stones. They can, therefore, be used in road and interior or exterior floor coverings.
基金supported by the following two grants:(i)Japan Society for the Promotion of Science(JSPS)KAKENHI Grant Number JP22H01581(i)National Research Counsil(NRC)of Sri Lanka Investigator Driven Grant Number 22-041.
文摘Concrete pavement often experiences accelerated deterioration due to water and chemical ingress through micro-cracks and surface voids.Particularly,the ingress of aggressive agents into the concrete matrix results in irreversible changes and deterioration on its endurance.Numerous studies unveiled that hydrophobic surface protection could be an inexpensive and effective way of enhancing the durability of concrete.This research work aims to assess the feasibility of bio-cement posttreatment for facilitating hydrophobic surface protection,thus enhancing the performance and durability of concrete blocks.Enzyme induced carbonate precipitation(EICP)is one of the promising bio-cement methods.Concrete blocks casted in four different grades were subjected to EICP treatment with different treatment schemes and recipes of cementation media.The treated blocks were tested for water absorption,ultrasonic pulse velocity(UPV)measurements,unconfined compressive strength(UCS),thermal performance,and scanning electron microscopy(SEM).The results indicated that the concrete blocks subjected to EICP posttreatment showed over a 55%reduction in water absorption,a 15%higher UCS and a 6.7%higher UPV when compared with control blocks.The SEM analysis suggested that the EICP posttreatment could enhance the durability of concrete paving blocks by enabling a layer of calcite on the surface and by plugging the transport pore channels of the concrete.Although most of the posttreatment strategies investigated herein were found to be operative,a better response was seen in the posttreatment by spraying scheme with 0.5 mol/L cementation media(CM).With the successful demonstration,the EICP treatment prior to the use of concrete blocks can be recommended to the pavement construction industry.
基金The research is funded by the NEXT GENERATION EU–PNRR project ex D.M.352/2022.The authors would like to thank ENI S.p.A for supporting this research.
文摘Many industrial sectors exploit fossil sources to develop useful and necessary materials for our needs,such as bituminous paving materials.Bitumen,a key component of asphalt mixtures,is derived from oil refining and its properties are influenced by the crude oil source and refining process,resulting in a significant carbon footprint.With growing awareness of resource depletion and environmental concerns,pavement researchers are exploring sustainable alternatives to reduce dependence on fossil sources.This includes a rising trend in using renewable materials like biomasses to produce bio-based binders as substitutes for bitumen,aiming for a more sustainable approach.Biomasses,including vegetal and animal wastes,and waste cooking oils,as substitutes for crude oil in the production of bio-binders.Through thermochemical conversion(TCC),such as pyrolysis,biomasses can be converted into bio-char and bio-oils,which can replace fossil-based components in binders.Researchers have utilized these bio-products to reduce the dependency on fossil fuels in binders.However,there are no set minimum requirements for bio-components in bio-based binders.As the percentage of replaced bitumen increases,various types of binders are produced,including modified bitumen,extended bitumen,and alternative binders,where the fossil replacement is gradual.Overall rheological tests on bio-binders,reveal that those containing biochar exhibit increased viscosity,stiffness,rutting resistance,and sometimes antioxidant properties.Conversely,bio-binders with bio-oils as bitumen substitutes show poorer performance at high temperatures but improved behavior at low temperatures.These results suggest that bio-binders could provide versatile solutions for various climatic and loading conditions in road construction.However,the development of pavement mixtures based on bio-binders has not been studied in depth and requires further attention to unlock its full potential.As sustainability considerations,including life cycle assessments(LCA)and life cycle cost analyses(LCC),are crucial aspects for future studies.It is essential not only to collect data on the performance characteristics of bio-binders but also to understand their environmental impact and recyclability.In-depth evaluations using methods such as LCA and LCC will provide valuable insights into the overall sustainability and long-term viability of these products.
基金supported by the Jiangsu Province College Student Innovation Training Program(Project No.20221127684Y)the Talent Startup project of Nanjing Institute of Technology(Project No.YKJ202117)。
文摘Tactile paving is a professional road facility to ensure the safe travel of people with visual impairment.However,there are many problems with tactile paving travel in practice.For one,some tactile paving is seriously damaged,and the other is the accumulation of obstacles.How to help visually impaired people recognize and locate obstacles in tactile paving is a problem worth studying.In this paper,image recognition technology is used to recognize the tactile paving pictures with obstacles,and an attention mechanism is used to optimize samples to improve recognition accuracy.
文摘The important parameters that influence the mechanical property of the pavinglayer on an orthotropic steel bridge deck are the paving layer thickness and modulus of the asphaltconcrete surfacing. Three important indices that control the typical failures of the paving layerare the maximum tensile stress of paving layer, the maximum shear stress between the steel deck andthe paving layer, and the maximum deflection on the paving surface. In this paper, the analyticalmodel of paving systems on orthotropic steel bridge deck is established, and the finite elementmethod is adopted to study the stress and strain of paving system. With the variation of asphaltconcrete modulus in high or low temperature season, the influences of paving layer thickness onthree control indices are researched. The results provide a theoretical basis for the determinationof thickness of the paving layer on the steel bridge deck.
文摘Many specifications of paving asphalts are closely related to their colloidal stability, which is, however, determined by their exact chemical compositions. The Yumen vacuum residue (YVR), the bottoms of a paraffinic crude oil is unfit for the production of highway paving asphalts directly, Neither are the de-oiled asphalts of the YVR. In this research a blending method and an optimal process of solvent de-asphalts are adopted to investigate the feasibility of formulating highway-paving asphalts from YVR. Results show that highway paving asphalts are formulated by blending solvent de-oiled asphalts with one or more of the materials including YVR, decanted oil from FCC process, and furfural extracts from lubricating base stocks. Further investigations indicate that adding oil decanted from FCC process to the solvent de-asphalting process can increase the de-asphalted oil production, improve the de-oiled asphalts quality, and thus optimize the refinery processes. The methodology of this research can be extended even to refineries processing non-paraffinic crude oils.
基金Funded by the Special Fund for Basic Scientific Research of Central Colleges,Chang'an University and Basic Research Support Program of Chang'an University(CHD2011SY005)
文摘The paving segregation of asphalt mixture was closely related to the structure size and using parameters for the screw distributor of paver,and the paving uniformity of the mixture was determined by the screw blade diameter,pitch,and the position of the mixture in the screw distributor.Through researching the kinematics of the mixture in the screw distributor,the mathematical model was established,and the mathematical model was related with structural parameters,used parameters and material parameters.Through the mathematical model,the various parameters on the screw distributor job performance were analyzed,and the unstable area,meta-stable area and stable area were determined.In the project,the full-scale test in actual project was conducted by using the AC25 mixture.By changing the using parameters compare the paving operations,the results show that,the reasonable parameter will greatly improve the uniformity of paving,and the surface proportion of structural depth of mixture decrease from the 2.13 to 1.60.
基金the financial support by Sinopec Innovation Foundation(118009-3)。
文摘With the rapid development of modern industry,high-grade paving asphalt is massively required to meet the demands for modern transportation.As one of additives,natural asphalt is indispensable since it can improve the performance of paving asphalt in all aspects.However,the application of non-renewable natural asphalt is increasingly restricted by its limited reserves.It is imperative to find alternative approaches to produce high-grade paving asphalt.Fluid catalytic cracking(FCC)slurry oil is an ideal soft component for producing paving asphalt due to its high content of aromatics and resins.However,its bad ageing resistance limits its application to only low-grade paving asphalt.In the present work,a novel approach for producing high-grade paving asphalt was investigated using chemically modified FCC slurry oil and deoiled asphalt(DOA).The FT-IR and NMR results showed that dehydrogenation and condensation reaction occurred during the ageing process.From a series of aliphatic alcohols and aldehydes,propanal was selected as a proper modifier to improve the ageing resistance of FCC slurry oil.The propanalmodified slurry oil possessed more substituted aromatic units and less aromatic hydrogen atoms than other modified slurry oils,thus showing better ageing resistance.With the increase of length of aliphatic chains in modifier,the modified slurry oil contained more and longer alkyl substituent group on aromatics.Compared with the cross-linked oil(slurry oil modified by cross-linking agent),modified slurry oil possessed similar ageing resistance but higher flowing ability.Also,the effect of operation conditions on the kinematic viscosity of modified slurry oil were investigated.Blended with modified slurry oil,the penetration ratio of asphalt product increased from 53.7 to 66.2,which met the standard of 70#paving asphalt.Both the microscopic observations and FT-IR results indicated that modification process effectively reduced the oxidation degree of asphalt product,thus increasing the ageing resistance.Consequently,with aid of this process,high-grade paving asphalt was readily produced from low value oil from downstream products of refinery,instead of the depleting natural asphalt.
基金Supported by the Progress Plan of Science & Technology of Wuhan Pingmei Wugang Unite Coking Chemical Corp.Ltd,Ltd.of WISCO(2008Z012)
文摘In order to enlarge the use of coal tar pitch(CTP) in paving road,CTP and 60th paving pitch (PP) were extracted by n-heptane,toluene and ethanol step by step in a Soxhlet apparatus.The three fractions of CTP and PP were detected using UV-absorption(UV-A),elemental analyses(EA) and nuclear magnetic resonance(NMR) firstly as a whole unit after quality characterization of physical nature of CTP and PP were finished.The CTP had more saturate aliphatic and residue compounds dissolved in ethanol.On the other hand there were more continental type structures of aromatic ring than that of PP.There was almost no residue in PP after extracted by ethanol.The results explained why CTP was crisp in cold winter and was soften in summer.The following research will focus on how to change the chemical construction of CTP into the relative similar structures with those of PP through adding polymer.
文摘The China Council for the Promotion of International Trade (CCPIT) held the Second Session of the Second Council of its National Congress in the latter half of July. Attending the session were officials in charge of foreign economic relations and trade from related Chinese ministries, provinces, municipalities and autonomous regions, chairmen of 46 local and 14 industrial sub-councils throughout
基金supported by the NIH (NEI grant RO1 EY 018132,Kirschstein-NRSA 4T32HD007505-20)
文摘Neurodegenerative diseases are a leading cause of disability worldwide,and despite significant resources put toward the discovery of potential therapeutic targets,there are currently no effective treatments.The rise of methods to derive and propagate stem cells in vitro offered
文摘The construction method of continuous paving of the upper and lower base of the water stable macadam base can improve the construction efficiency,overcome the quality problems of the traditional layered paving of the upper and lower base,such as untimely curing,slow construction,poor interlayer bonding,contraction joint and interlayer,so as to ensure the construction quality of the water stable macadam.It is also the promotion and application of new technology.
文摘This year is the 25th anniversary of the normalization of Sino-Japanese Rela-tions. In the past 25 years, relations between the two countries were by and largegood, but problems never ceased to occur. Some problems were considered pre-dictable but others were quite weird, to the Chinese part at least. To improve thebilateral relationship in the 21st Century, both Beijing and Tokyo need to
文摘In the construction of asphalt mixture pavement,there are many paving construction procedures,high requirements for machinery and personnel,unreasonable technology and so on.In this paper,the millimeter-scale 3D automatic paving control technology of asphalt mixture pavement is studied with an engineering example.From the analysis of the test results in the later stage of construction,it can be seen that the technology has achieved the goal of high precision paving,and the successful application of the technology provides valuable reference experience for similar asphalt concrete pavement construction in the future.
文摘Tremolite group minerals could be present in the aggregate used as filler in the mix asphalt floor in the road surfaces and are subject to wear for vehicular traffic and materials ageing.Dust produced by the degradation of asphalt surfaces can disperse tremolite group minerals present in road paving causing exposure by asbestos fiber to an increasing number of people and animals.In recent years,attention has been focused on naturally occurring asbestos(NOA)as the greatest frequency of lung cancer has been observed in environments characterized by rocks and soils rich in Tremolite that characterize asbestos minerals.Asphalt samples object of this study were collected in a motorway segment of the Lombardia Region(north of Italy)for an exposure assessment research on road paving workers.The evaluation was performed using a metrological approach based on petrographic and mineralogical analyses in order to reduce the epidemiologic risks and to define the best treatment strategies on waste management with sustainable costs in fulfilment of Council Directive 67/548/EEC(1967)and EC Regulation 1272/2008(2008)(Paglietti et al.,2016).The fibers are generally not broken down to other compounds in the environment,but asbestos hazard could be related to the occurrence of tremolite fiber in road paving arises when natural weathering processes(e.g.,erosion)or human activities(e.g.,continuous passage of motorized vehicles)separate and break down the fibers,which could be lost into the environment as airborne and easily penetrate into the human respiratory tract(Punturo et al.,2019).Despite this,this work is not an epidemiological risk analysis but obtained data could be useful to other specialists to define the exposure risks.
文摘The improvement of road surface engineering construction quality is helpful to create safe and comfortable travel conditions for people and prevent traffic accidents. With the acceleration of highway construction in our country, the standard of pavement construction is also improving. Only by strictly following the national and industry standards can the service life of the pavement be prolonged and the subsequent maintenance and management work be guaranteed. Especially in asphalt paving, temperature, humidity and geological conditions will have different degrees of influence, which brings great difficulty to the construction. Performance parameters such as compactness and cohesiveness of asphalt mixture also determine the overall paving quality. In the construction, the effect of various factors should be considered, and a practical construction organization scheme should be prepared according to the construction requirements and actual conditions of highway pavement engineering. In addition, ensure that the paving technology meets the standard requirements, strengthen the construction standardization and reduce the probability of pavement diseases.
文摘The stability of roads in cities directly affects the safety of traffic and transportation.In the process of pavement laying,relevant personnel should use permeable paving materials in the process of construction.Based on the analysis of road drainage requirements,traditional paving materials have relatively poor water permeability,which leads to ponding problems during road use[1].Within this frame of reference,beginning with the characteristics of permeable paving materials,this paper makes an in-depth exploration on practical application measures.
文摘China’s largest private equity fund focusing on African investments boosts its footprint on the continent THE China-Africa Development Fund (CADFund),which has traditionally kept a low profile,has often been seen in the public spotlight over the past year. The fund and cement producer,Jidong Development Group,decided to invest approximately $220 million to set up a cement plant
文摘No stranger could detect anything unnatural to see the 14-year-old Zhang Lizheng burst into the house with the greeting remark, "Mom, I’m back!" He’s just returned from school. "You’re the last to come back today," says the "Mom" indulgently, taking off the boy’s jacket and hanging it on the clothes rack next to the door. "Wash your hands and dinner is ready." On the round dinner table lie several dishes and six sets of bowls and chopsticks. "You’ll also have your favorite scrambled eggs and tomatoes tonight," smiles the lady in her late 20s, who looks too young to be a mother of four boys.
文摘THE Ninth BRICS Summit will be held in China＇s Xiamen City in early September. The last time China hosted the BRICS Summit was in 2011, when South Africa was accepted as a full member. South Africa＇s accession not only strengthens the BRICS countries＇ direct links with the Afri- can continent, but also broadens BRICS in terms of economic aggregates, population and area. More importantly, the move has greatly enhanced the representative- ness of the mechanisms as its coverage expanded from Asia, Europe and America to Africa, making it an economic coopera- tion mechanism for emerging economies covering the whole world,
