Zhang Ailin created so many various kinds of female charaters in her novels;females who own distinct characters and identities just have similar fates and struggles.This paper tries to probe into the similar fates and...Zhang Ailin created so many various kinds of female charaters in her novels;females who own distinct characters and identities just have similar fates and struggles.This paper tries to probe into the similar fates and struggles of two heroines with different identities in the same social background by analysing the novel Gimmal and Crumbs of Agalloch Eaglewood-the First Incense Burner from perspective of feminism.展开更多
BACKGROUND Crumbs homolog 2(CRB2)is a recently discovered gene that is closely related to the maintenance of normal polarity in podocytes;mutations can directly lead to steroid-resistant nephrotic syndrome(SRNS).Howev...BACKGROUND Crumbs homolog 2(CRB2)is a recently discovered gene that is closely related to the maintenance of normal polarity in podocytes;mutations can directly lead to steroid-resistant nephrotic syndrome(SRNS).However,the characteristics of nephrotic syndrome(NS)caused by CRB2 mutations have not been described.CASE SUMMARY We report a novel compound heterozygous mutation of the CRB2 gene in two siblings with SRNS.The two siblings had edema,proteinuria,hypoproteinemia and hyperlipidemia.Both their father and mother had normal phenotypes(no history of NS).Whole exon sequencing(WES)of the family showed a novel compound heterozygous mutation,c.2290(exon 8)C>T and c.3613(exon 12)G>A.Glucocorticoid therapy(methylprednisolone pulse therapy or oral prednisone)and immunosuppressive agents(tacrolimus)had no effect.During a 3-year follow-up after genetic diagnosis by WES,proteinuria persisted,but the patient was healthy.CONCLUSION CRB2 mutations related to SRNS often occur in exons 7,10,and 12.Clinical manifestations of SRNS caused by CRB2 mutations are often less severe than in other forms of SRNS.展开更多
Although the unique organization of vertebrate cone mosaics was first described long ago,both their underlying molecular basis and physiological significance are largely unknown.Here,we demonstrate that Crumbs protein...Although the unique organization of vertebrate cone mosaics was first described long ago,both their underlying molecular basis and physiological significance are largely unknown.Here,we demonstrate that Crumbs proteins,the key regulators of epithelial apical polarity,establish the planar cellular polarity of photoreceptors in zebrafish.Via heterophilic Crb2a-Crb2b interactions,the apicobasal polarity protein Crb2b restricts the asymmetric planar distribution of Crb2a in photoreceptors.The planar polarized Crumbs proteins thus balance intercellular adhesions and tension between photoreceptors,thereby stabilizing the geometric organization of cone mosaics.Notably,loss of Crb2b in zebrafish induces a nearsightedness-like phenotype in zebrafish accompanied by an elongated eye axis and impairs zebrafish visual perception for predation.These data reveal a detailed mechanism for cone mosaic homeostasis via previously undiscovered apical-planar polarity coordination and propose a pathogenic mechanism for nearsightedness.展开更多
In the past two decades, extensive studies have focused on a group of so-called polarity proteins that play conserved and essential functions in establishing and maintaining cell polarity in epithelial cells. Among th...In the past two decades, extensive studies have focused on a group of so-called polarity proteins that play conserved and essential functions in establishing and maintaining cell polarity in epithelial cells. Among them, Crumbs （Crb） is the only trans- membrane polarity protein characterized to date （Tepass et al.,展开更多
The addition of high-content crumb rubber(HCCR)in asphalt can effectively address waste tire pollution and provide sustainable environmental and economic advantages.However,the practical application of conventional ru...The addition of high-content crumb rubber(HCCR)in asphalt can effectively address waste tire pollution and provide sustainable environmental and economic advantages.However,the practical application of conventional rubberized binders is significantly limited by high viscosity and poor storage stability.To address these issues,researchers have pretreated crumb rubber(CR)with oil,but high-temperature performance remains insufficient.Therefore,this study aimed to optimize the viscosity,storage stability,and rheological properties of high-content crumb rubber-modified asphalt(HCCRMA)by varying the pretreatment levels of CR and incorporating various additives,including styrene-butadiene-styrene(SBS),deoiled asphalt(DA),or recycled low-density polyethylene(RLDPE).In addition,CR was pretreated with waste cooking oil(WCO)at various ratios,pre-swelling temperatures,and times.The results show that DA exhibits excellent storage stability and lower viscosity compared with other modifiers in HCCRMA,and the 4%RLDPE with pretreated HCCR has the greatest high-temperature rutting resistance.The inclusion of RLDPE increases the stiffness and elasticity of the modified asphalt,which results in greater high-temperature performance.Additionally,the fluorescence microscopy(FM)test confirms that SBS exhibits better dispersion than other modifiers and forms a more homogeneous phase separation in the HCCRMA.All in all,this research achieved an optimal balance of storage stability and rheological properties in asphalt modified with pretreated HCCR and 6%SBS,which provides a valuable reference for performance improvement of HCCR-modified binders.展开更多
Enhancing rubber-bitumen compatibility is crucial to improve pavement performance and durability.To investigate the compatibility improvement between H2O2-activated waste crumb rubber(AWCR)and bitumen,coarse and fine ...Enhancing rubber-bitumen compatibility is crucial to improve pavement performance and durability.To investigate the compatibility improvement between H2O2-activated waste crumb rubber(AWCR)and bitumen,coarse and fine waste crumb rubber(WCR)were treated and analyzed through multi-scale characterization and molecular simulation.Microstructure and chemical changes of WCR and AWCR were analyzed with scanning electron microscope(SEM),contact angle tests and Fourier transform infrared spectroscopy(FTIR).Compatibility was also indirectly evaluated through modified boiling tests and storage stability tests.Besides,molecular dynamics was used to explore the interaction between WCR/AWCR and bitumen.SEM,contact angle,and FTIR results showed bond breakage of C=C and C–C and increased polar groups like–OH and–COOH in AWCR,resulting in a rougher texture and higher surface energy.Compared with WCR,AWCR showed a lower bitumen stripping rate after boiling,and the binder with AWCR also had a lower softening point difference and segregation rate after storage.Molecular dynamics simulations further confirmed that AWCR has a closer solubility parameter and higher binding energy to bitumen than WCR,reflected in a relatively slower diffusion rate.This study provides comprehensive evidence for an eco-friendly method of WCR surface treatment for more efficient recycling of tire rubber in asphalt pavements.展开更多
Starch retrogradation is a primary contributor to the staling of bread.The impact of the surfactant glyceryl monostearate(GMS)on the structure and retrogradation characteristics of wheat starch gels was explored durin...Starch retrogradation is a primary contributor to the staling of bread.The impact of the surfactant glyceryl monostearate(GMS)on the structure and retrogradation characteristics of wheat starch gels was explored during storage at 4℃ for 2 h and 5 d.In this research,the incorporation of GMS(0.14%,W/W,based on flour weight)significantly reduced the crumb firmness(P<0.05).Molecular dynamics simulation vividly demonstrated the formation process of the single-helical amylose-GMS complex within 150 ns during the short-term retrogradation process of cooling the gelatinized starch for 2 h.X-ray diffraction analysis revealed that GMS slightly decreased the relative crystallinity of starch from 8.9%to 7.8%during long-term retrogradation.The reduction in R1047/1022 detected by Fourier-transform infrared spectroscopy indicated that GMS could reduce the degree of retrogradation.Solid-state ^(13)C NMR analysis showed a characteristic resonance peak at 31.7 ppm for the GMSstarch complex.This study indicates that GMS holds great application potential in retarding starch retrogradation.展开更多
Road traffic noise is a significant environmental issue in urban areas with major health and economic implications for communities.Thus,a comprehensive understanding of tire/road noise mechanism is crucial for road pa...Road traffic noise is a significant environmental issue in urban areas with major health and economic implications for communities.Thus,a comprehensive understanding of tire/road noise mechanism is crucial for road pavement engineering.This study evaluates the noise behaviour of six innovative microsurfacing mixtures incorporating natural and artificial aggregates(geopolymers and crumb rubber)with varying particle size distributions and binders.A 2D laser analysis aims at collecting surface texture indicators,while noise-related indicators were derived according to ISO 10844 standards.Noise levels were predicted using the SPERoN^(R)model(statistical physical explanation of rolling noise),analysing the vibro-dynamic and the aerodynamic contributions separately.Correlations between tire/road noise levels predicted by the model and surface texture indicators elucidate the key factors influencing noise generation mechanism.The findings indicate that lower nominal maximum aggregate size(NMAS)and uniformly shaped artificial aggregates substantially mitigate rolling noise.Moreover,profiles with negative skewness and positive kurtosis exhibit reduced noise generation.The study highlights the limitations of traditional indicators like the estimated noise difference due to texture(ENDT)and highlights the g-factor from the Abbott curve as a more reliable predictor of pavement noise properties.These findings provide valuable insights for designing low-noise pavements with enhanced performance,offering new perspectives on the noise behaviour and acoustic properties of microsurfacing.展开更多
In this study the stress–strain characteristics of sand-ground rubber mixtures are investigated in the sandlike zone,at different confining pressures,using hollow cylinder specimens subjected to torsional monotonic a...In this study the stress–strain characteristics of sand-ground rubber mixtures are investigated in the sandlike zone,at different confining pressures,using hollow cylinder specimens subjected to torsional monotonic and cyclic loading.Under monotonic loading a mixture of sand-ground rubber with 10% and 25% rubber content show more contraction behaviour than that observed in a pure sand specimen.Phase transformation point in these mixtures are located on a larger shear strain.As expected,the shear strength of specimens decreases with increase of ground rubber content.However,with increasing of effective confining pressure,the loss in shear strength of the mixture is decreased.In addition,a mixture with 25% ground rubber shows a smaller loss in shear strength compared to a mixture with 10% ground rubber mixture.Under cyclic loading mixtures with 10% and 25% ground rubber have similar liquefaction resistance,especially at confining pressures of 110 k Pa and 260 k Pa.Therefore,by using of the mixture with 25% ground rubber,a larger volume of scrap tires could be recycled.The addition of ground rubber to sand would affect the shear strain variation and excess pore water pressure trends,and this effect was further intensified with increasing ground rubber percentage.展开更多
Bitumen was modified with desulfurized crumb rubber (DCR) in the present of reac tive additives. The effect of the kinds and content of the reactive additive on prop erties of DCR modified bitumen (DCRMB) was investi...Bitumen was modified with desulfurized crumb rubber (DCR) in the present of reac tive additives. The effect of the kinds and content of the reactive additive on prop erties of DCR modified bitumen (DCRMB) was investigated. The morphology of DCRMB was characterized by SEM and the changes of the chemical structure of DCRMB wit hout and with the addition of the reactive additive were analyzed by FTIR. The e xperimented results show that the softening point,the elasticity recovery and th e storage stability of DCRMB were improved significantly by the addition of the reactive additive. This is because that a network structure of rubber in DCRMB w as formed and the chemical reaction between C=C double bonds in bitumen and DCR has happened after the reactive additive was added into DCRMB.展开更多
To investigate the mechanism of asphalt modification by crumb rubber,the interactions between FCC slurry and rubber particles were evaluated at different temperatures and time.The rules of the change in mass of SARA c...To investigate the mechanism of asphalt modification by crumb rubber,the interactions between FCC slurry and rubber particles were evaluated at different temperatures and time.The rules of the change in mass of SARA composition in FCC slurry were obtained before and after its interaction with rubber particles,which showed that crumb rubber not only absorbed saturates and aromatics but also resins.Asphaltenes promoted the desulfurization or degradation of crumb rubber during the interaction between asphalt and crumb rubber.展开更多
Traditional techniques for treatment of waste rubber, such as burning, generate some highly non- degradable synthetic materials that cause unrepairable environmental damages by releasing heavy metals, such as arsenic,...Traditional techniques for treatment of waste rubber, such as burning, generate some highly non- degradable synthetic materials that cause unrepairable environmental damages by releasing heavy metals, such as arsenic, chromium, lead, manganese and nickel. For this, scrap tires are used as light- weight alternative materials in many engineering applications, such as retaining wall backfilling. In the present study, 90 laboratory models were prepared to evaluate the stability of mechanically stabilized earth （MSE） walls with plate anchors. Then, the bearing capacity and horizontal displacements of the retaining walls were monitored by exerting a static loading to investigate the effects of adding different contents （5 wt%, 10 wt%, 15 wt% and 20 wt%） of recycled crumb rubber （RCR） to the fill of a mechanically stabilized retaining wall with plate anchors. To visualize the critical slip surface of the wall, the particle image velocimetry （PIV） technique was employed. Results showed that the circular anchor plates almost continually provided a higher bearing capacity and wall stability than the square plates. Moreover, the backfill with 15 wt% RCR provided the maximum bearing capacity of the wall. Increasing the weight percentage of RCR to 20 wt% resulted in a significant reduction in horizontal displacement of the wall, which occurred due to the decrease in lateral earth pressure against the whole walls. An increase in RCR content resulted in the decrease in the formation of failure wedge and the expansion of the wall slip surface, and the failure wedge did not form in the sand mixtures with 15 wt% and 20 wt% RCRs.展开更多
A test for crumb rubber modified asphalt containing 20% crumb rubber particles（30 mesh） was performed using a scanning electron microscope（SEM）.The experimental results indicate that the crumb rubber particles are...A test for crumb rubber modified asphalt containing 20% crumb rubber particles（30 mesh） was performed using a scanning electron microscope（SEM）.The experimental results indicate that the crumb rubber particles are evenly distributed in the asphalt.Shear rate sweep and shear-temperature sweep tests on the crumb rubber modified asphalt at-20-80 ℃ using a dynamic shear rheology（DSR） instrument,were carried out.The tests show that the complex modulus decreases with increasing temperature;at equivalent temperature,higher load frequencies lead to a larger complex modulus,and this value increasingly decreases as the temperature increases;the phase angle increases with temperature and decreases as the load frequency increases.It can be concluded that the rutting resistance limiting temperature of crumb rubber modified asphalt is 78 ℃,and the anti-fatigue limiting temperature is 16 ℃,which shows that the asphalt has preferable rutting resistance characteristics at high temperature,as well as anti-fatigue characteristics.In addition,the complex modulus master curve at different temperatures was plotted according to the time temperature equivalence principle,which allows the study of the dynamic state behavior of crumb rubber modified asphalt at a wide range of load frequency.展开更多
In this paper,organic montmorillonite(OMMT)was added into crumb rubber modified asphalt(CRMA)to improve its high temperature performance,anti-aging performance and storage stability.The effects of different OMMT conte...In this paper,organic montmorillonite(OMMT)was added into crumb rubber modified asphalt(CRMA)to improve its high temperature performance,anti-aging performance and storage stability.The effects of different OMMT content on properties of CRMA were studied.The rutting factor obtained by dynamic shear rheological(DSR)test was adopted to evaluate the high-temperature performance.The creep stiffness and m value determined by the bending beam rheometer(BBR)test were employed to evaluate the low-temperature performance.The softening point,ductility,rutting factor before and after rolling thin film ovens test(RTFOT)and pressure aging vessel test(PAV)were compared to characterize the aging properties.Moreover,the segregation test after being reserved for 48 h and 7 d was conducted,and the softening point and rutting factor of upper and lower layers of segregation pipe were adopted to evaluate the storage stability.The results indicated that the high-temperature performance and anti-aging performance were developed with the increasing content of OMMT,while the low-temperature performance deteriorated.The storage stability was improved with the increasing content of OMMT before the content exceeded 4%,after which the storage stability declined.Taking account of all factors,it is suggested that the optimum content of OMMT is 3%−4%.展开更多
The microstructures of general crumb rubber(CR), dynamic desulfurized crumb rubber(DDCR) and high speed agitation desulfurized crumb rubber(HSADCR) modified bitumens were investigated by a fluorescence microscope, and...The microstructures of general crumb rubber(CR), dynamic desulfurized crumb rubber(DDCR) and high speed agitation desulfurized crumb rubber(HSADCR) modified bitumens were investigated by a fluorescence microscope, and the physical properties of these three modified bitumens were studied.The results show that the dynamic desulfuration can improve the swelling capacity of crumb rubber in bitumen by destroying the sulfuratized bond of the crumb rubber,but the reunion of rubber particles during dynamic desulfuration also makes the swelling and the DDCR in bitumen difficult, so properties of the DDCR modified bitumen are not superior to the general crumb rubber modified bitumen.However,high speed agitation desulfuration can not only improve the swelling capacity of crumb rubber in bitumen,but also avoid the reunion of rubber particles,so some properties of bitumen can be improved by the modification of HSADCR.展开更多
In this study, the efficiency of bitumen and asphalt mixtures modified with crumb rubber(CR) and recycled glass powder(RGP) is evaluated. From an environmental point of view, the application of RGP in asphalt mixtures...In this study, the efficiency of bitumen and asphalt mixtures modified with crumb rubber(CR) and recycled glass powder(RGP) is evaluated. From an environmental point of view, the application of RGP in asphalt mixtures is considered beneficial since it prevents accumulation of waste glass in the natural environment. Rheological and mechanical properties of modified bitumen samples were investigated by laboratory methods such as bitumen conventional tests and dynamic shear rheometer(DSR), and also by asphalt mixture performance tests including Marshall stability, indirect tensile strength(ITS),compressive strength, and indirect tensile stiffness modulus. The results showed that the application of RGP in place of CR has no negative impact on the efficiency of bitumen and asphalt mixtures and even improves their engineering properties except for the toughness index(TI). Moreover, a modification with 5% CR and 5% RGP in asphalt mixtures results in the best overall performance.展开更多
In this paper, properties of new kind of modified bitumen are presented. Bituminous binder was modified with mix modification using polymer and additive of crumb rubber. Terminal blend process at the refinery was appl...In this paper, properties of new kind of modified bitumen are presented. Bituminous binder was modified with mix modification using polymer and additive of crumb rubber. Terminal blend process at the refinery was applied to produce the mixed modified binder. Laboratory tests were focused on the characterization of the properties of 45/80-55 CR binder with comparison to reference 50/70 and conventional polymer modified 45/80-55 bitumen. Based on conventional binder tests such as penetration, softening point and Fraass breaking point as well as BBR （bending beam rheometer） and DSR （dynamic shear rheometer） tests, rheological properties were investigated. For determination of stability of the polymer and crumb rubber, modified bitumen tube testing method was used. Based on the results analysis, improvement of the viscoelastic properties of polymer and crumb rubber modified bitumen was observed. Conventional properties and stability tests showed that it is possible to pass standard requirements for polymer modified bitumen. Mixed modification and terminal blend allow to use crumb rubber as a modifier with elimination of the separation of crumb rubber during transportation and storage at high temperature. In this paper, experience from filed sections with use of the asphalt mixture with new kind of modified bitumen is presented.展开更多
Crumb rubber modified asphalt containing 20 percent crumb rubber particles of 30 mesh has been examined by Scanning Electron Microscope （SEM） to observe the microcosmic appearance and the characteristic distribution...Crumb rubber modified asphalt containing 20 percent crumb rubber particles of 30 mesh has been examined by Scanning Electron Microscope （SEM） to observe the microcosmic appearance and the characteristic distribution of crumb rubber particles in asphalt. The SEM pictures reveal that the crumb rubber particles distribute evenly in the asphalt and they are compatible well with asphalt. The shear creep test of crumb rubber modified asphalt was carried out at -10 ℃ and 40 ℃ by Dynamic Shear Rheology （DSR）. The shearing deformation at different temperature and creep stiffness modulus curve at loading stage of crumb rubber modified asphalt have been measured. The stiffness modulus of crumb rubber modified asphalt is much temperature sensitive and it decays much quick at the early stage of loading than normal asphalt. The rate of decay of stiffness modulus is slow at the subsequent stage and stiffness modulus approaches to a stable value at the final stage at a higher temperature. In addition, Burgers model is suitable to describe and simulate experimental results of viscoelastic properties of the crumb rubber modified asphalt.展开更多
文摘Zhang Ailin created so many various kinds of female charaters in her novels;females who own distinct characters and identities just have similar fates and struggles.This paper tries to probe into the similar fates and struggles of two heroines with different identities in the same social background by analysing the novel Gimmal and Crumbs of Agalloch Eaglewood-the First Incense Burner from perspective of feminism.
文摘BACKGROUND Crumbs homolog 2(CRB2)is a recently discovered gene that is closely related to the maintenance of normal polarity in podocytes;mutations can directly lead to steroid-resistant nephrotic syndrome(SRNS).However,the characteristics of nephrotic syndrome(NS)caused by CRB2 mutations have not been described.CASE SUMMARY We report a novel compound heterozygous mutation of the CRB2 gene in two siblings with SRNS.The two siblings had edema,proteinuria,hypoproteinemia and hyperlipidemia.Both their father and mother had normal phenotypes(no history of NS).Whole exon sequencing(WES)of the family showed a novel compound heterozygous mutation,c.2290(exon 8)C>T and c.3613(exon 12)G>A.Glucocorticoid therapy(methylprednisolone pulse therapy or oral prednisone)and immunosuppressive agents(tacrolimus)had no effect.During a 3-year follow-up after genetic diagnosis by WES,proteinuria persisted,but the patient was healthy.CONCLUSION CRB2 mutations related to SRNS often occur in exons 7,10,and 12.Clinical manifestations of SRNS caused by CRB2 mutations are often less severe than in other forms of SRNS.
基金supported by National Natural Science Foundation of China projects (81770938 to J.Z. and 81570822 to K.Y.)the Zhejiang Provincial Natural Science Foundation project (LZ15H120001 to J.Z.)the Fundamental Research Funds for the Central Universities (2016FZA7010 and 2017FZA7001 to J.Z.)。
文摘Although the unique organization of vertebrate cone mosaics was first described long ago,both their underlying molecular basis and physiological significance are largely unknown.Here,we demonstrate that Crumbs proteins,the key regulators of epithelial apical polarity,establish the planar cellular polarity of photoreceptors in zebrafish.Via heterophilic Crb2a-Crb2b interactions,the apicobasal polarity protein Crb2b restricts the asymmetric planar distribution of Crb2a in photoreceptors.The planar polarized Crumbs proteins thus balance intercellular adhesions and tension between photoreceptors,thereby stabilizing the geometric organization of cone mosaics.Notably,loss of Crb2b in zebrafish induces a nearsightedness-like phenotype in zebrafish accompanied by an elongated eye axis and impairs zebrafish visual perception for predation.These data reveal a detailed mechanism for cone mosaic homeostasis via previously undiscovered apical-planar polarity coordination and propose a pathogenic mechanism for nearsightedness.
基金supported by the grants from the National Institutes of Health of USA(NCRR R21RR024869, NIGMS RO1GM086423 and RO1GM121534 to Y.H.)the Start-up Foundation from Nanjing Medical University (2012RC04 to J.H.)University of Pittsburgh Medical School Center for Biologic Imaging was supported by the grant 1S100D019973-01 from NIH, USA
文摘In the past two decades, extensive studies have focused on a group of so-called polarity proteins that play conserved and essential functions in establishing and maintaining cell polarity in epithelial cells. Among them, Crumbs （Crb） is the only trans- membrane polarity protein characterized to date （Tepass et al.,
基金supported by the Transportation Science and Technology Program of Henan Province(grant number:2023-4-2)the Key Research and Development Program of Ningxia Science and Technology Department(grant number:2022BEG02008)+2 种基金China Communications Construction Group Co.,Ltd.Science and Technology R&D Project(grant number:2021KJW02)the Research and Development Program of Henan Transportation Investment Group Co.,Ltd.(grant number:HNJT2025-1-9)the Postdoctoral Fellowship Program of CPSF(grand number:GZC20251139).
文摘The addition of high-content crumb rubber(HCCR)in asphalt can effectively address waste tire pollution and provide sustainable environmental and economic advantages.However,the practical application of conventional rubberized binders is significantly limited by high viscosity and poor storage stability.To address these issues,researchers have pretreated crumb rubber(CR)with oil,but high-temperature performance remains insufficient.Therefore,this study aimed to optimize the viscosity,storage stability,and rheological properties of high-content crumb rubber-modified asphalt(HCCRMA)by varying the pretreatment levels of CR and incorporating various additives,including styrene-butadiene-styrene(SBS),deoiled asphalt(DA),or recycled low-density polyethylene(RLDPE).In addition,CR was pretreated with waste cooking oil(WCO)at various ratios,pre-swelling temperatures,and times.The results show that DA exhibits excellent storage stability and lower viscosity compared with other modifiers in HCCRMA,and the 4%RLDPE with pretreated HCCR has the greatest high-temperature rutting resistance.The inclusion of RLDPE increases the stiffness and elasticity of the modified asphalt,which results in greater high-temperature performance.Additionally,the fluorescence microscopy(FM)test confirms that SBS exhibits better dispersion than other modifiers and forms a more homogeneous phase separation in the HCCRMA.All in all,this research achieved an optimal balance of storage stability and rheological properties in asphalt modified with pretreated HCCR and 6%SBS,which provides a valuable reference for performance improvement of HCCR-modified binders.
基金supported by the research project“Green-health-safety Nexus for New Urban Spaces-GreeNexUS”(HORIZON MSCA-2021 DN,Marie Sklodowska-Curie Actions)Grant Agreement No.101073437:research grant under the title"Impact Absorbing Pavements with Improved Accessibility Features(DC9-IAP)".
文摘Enhancing rubber-bitumen compatibility is crucial to improve pavement performance and durability.To investigate the compatibility improvement between H2O2-activated waste crumb rubber(AWCR)and bitumen,coarse and fine waste crumb rubber(WCR)were treated and analyzed through multi-scale characterization and molecular simulation.Microstructure and chemical changes of WCR and AWCR were analyzed with scanning electron microscope(SEM),contact angle tests and Fourier transform infrared spectroscopy(FTIR).Compatibility was also indirectly evaluated through modified boiling tests and storage stability tests.Besides,molecular dynamics was used to explore the interaction between WCR/AWCR and bitumen.SEM,contact angle,and FTIR results showed bond breakage of C=C and C–C and increased polar groups like–OH and–COOH in AWCR,resulting in a rougher texture and higher surface energy.Compared with WCR,AWCR showed a lower bitumen stripping rate after boiling,and the binder with AWCR also had a lower softening point difference and segregation rate after storage.Molecular dynamics simulations further confirmed that AWCR has a closer solubility parameter and higher binding energy to bitumen than WCR,reflected in a relatively slower diffusion rate.This study provides comprehensive evidence for an eco-friendly method of WCR surface treatment for more efficient recycling of tire rubber in asphalt pavements.
基金supported by the Zhejiang Provincial Natural Science Foundation of China(LQ23C200003)National Natural Science Foundation of China(32202076)Natural Science Foundation of Shandong Province(Project No.ZR2023QC083).
文摘Starch retrogradation is a primary contributor to the staling of bread.The impact of the surfactant glyceryl monostearate(GMS)on the structure and retrogradation characteristics of wheat starch gels was explored during storage at 4℃ for 2 h and 5 d.In this research,the incorporation of GMS(0.14%,W/W,based on flour weight)significantly reduced the crumb firmness(P<0.05).Molecular dynamics simulation vividly demonstrated the formation process of the single-helical amylose-GMS complex within 150 ns during the short-term retrogradation process of cooling the gelatinized starch for 2 h.X-ray diffraction analysis revealed that GMS slightly decreased the relative crystallinity of starch from 8.9%to 7.8%during long-term retrogradation.The reduction in R1047/1022 detected by Fourier-transform infrared spectroscopy indicated that GMS could reduce the degree of retrogradation.Solid-state ^(13)C NMR analysis showed a characteristic resonance peak at 31.7 ppm for the GMSstarch complex.This study indicates that GMS holds great application potential in retarding starch retrogradation.
基金funded by the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement N°765057(SAFERUP Project).
文摘Road traffic noise is a significant environmental issue in urban areas with major health and economic implications for communities.Thus,a comprehensive understanding of tire/road noise mechanism is crucial for road pavement engineering.This study evaluates the noise behaviour of six innovative microsurfacing mixtures incorporating natural and artificial aggregates(geopolymers and crumb rubber)with varying particle size distributions and binders.A 2D laser analysis aims at collecting surface texture indicators,while noise-related indicators were derived according to ISO 10844 standards.Noise levels were predicted using the SPERoN^(R)model(statistical physical explanation of rolling noise),analysing the vibro-dynamic and the aerodynamic contributions separately.Correlations between tire/road noise levels predicted by the model and surface texture indicators elucidate the key factors influencing noise generation mechanism.The findings indicate that lower nominal maximum aggregate size(NMAS)and uniformly shaped artificial aggregates substantially mitigate rolling noise.Moreover,profiles with negative skewness and positive kurtosis exhibit reduced noise generation.The study highlights the limitations of traditional indicators like the estimated noise difference due to texture(ENDT)and highlights the g-factor from the Abbott curve as a more reliable predictor of pavement noise properties.These findings provide valuable insights for designing low-noise pavements with enhanced performance,offering new perspectives on the noise behaviour and acoustic properties of microsurfacing.
文摘In this study the stress–strain characteristics of sand-ground rubber mixtures are investigated in the sandlike zone,at different confining pressures,using hollow cylinder specimens subjected to torsional monotonic and cyclic loading.Under monotonic loading a mixture of sand-ground rubber with 10% and 25% rubber content show more contraction behaviour than that observed in a pure sand specimen.Phase transformation point in these mixtures are located on a larger shear strain.As expected,the shear strength of specimens decreases with increase of ground rubber content.However,with increasing of effective confining pressure,the loss in shear strength of the mixture is decreased.In addition,a mixture with 25% ground rubber shows a smaller loss in shear strength compared to a mixture with 10% ground rubber mixture.Under cyclic loading mixtures with 10% and 25% ground rubber have similar liquefaction resistance,especially at confining pressures of 110 k Pa and 260 k Pa.Therefore,by using of the mixture with 25% ground rubber,a larger volume of scrap tires could be recycled.The addition of ground rubber to sand would affect the shear strain variation and excess pore water pressure trends,and this effect was further intensified with increasing ground rubber percentage.
基金Funded by the Foundation of State Laboratory of Heavy Oil Processing(2002 13)
文摘Bitumen was modified with desulfurized crumb rubber (DCR) in the present of reac tive additives. The effect of the kinds and content of the reactive additive on prop erties of DCR modified bitumen (DCRMB) was investigated. The morphology of DCRMB was characterized by SEM and the changes of the chemical structure of DCRMB wit hout and with the addition of the reactive additive were analyzed by FTIR. The e xperimented results show that the softening point,the elasticity recovery and th e storage stability of DCRMB were improved significantly by the addition of the reactive additive. This is because that a network structure of rubber in DCRMB w as formed and the chemical reaction between C=C double bonds in bitumen and DCR has happened after the reactive additive was added into DCRMB.
文摘To investigate the mechanism of asphalt modification by crumb rubber,the interactions between FCC slurry and rubber particles were evaluated at different temperatures and time.The rules of the change in mass of SARA composition in FCC slurry were obtained before and after its interaction with rubber particles,which showed that crumb rubber not only absorbed saturates and aromatics but also resins.Asphaltenes promoted the desulfurization or degradation of crumb rubber during the interaction between asphalt and crumb rubber.
文摘Traditional techniques for treatment of waste rubber, such as burning, generate some highly non- degradable synthetic materials that cause unrepairable environmental damages by releasing heavy metals, such as arsenic, chromium, lead, manganese and nickel. For this, scrap tires are used as light- weight alternative materials in many engineering applications, such as retaining wall backfilling. In the present study, 90 laboratory models were prepared to evaluate the stability of mechanically stabilized earth （MSE） walls with plate anchors. Then, the bearing capacity and horizontal displacements of the retaining walls were monitored by exerting a static loading to investigate the effects of adding different contents （5 wt%, 10 wt%, 15 wt% and 20 wt%） of recycled crumb rubber （RCR） to the fill of a mechanically stabilized retaining wall with plate anchors. To visualize the critical slip surface of the wall, the particle image velocimetry （PIV） technique was employed. Results showed that the circular anchor plates almost continually provided a higher bearing capacity and wall stability than the square plates. Moreover, the backfill with 15 wt% RCR provided the maximum bearing capacity of the wall. Increasing the weight percentage of RCR to 20 wt% resulted in a significant reduction in horizontal displacement of the wall, which occurred due to the decrease in lateral earth pressure against the whole walls. An increase in RCR content resulted in the decrease in the formation of failure wedge and the expansion of the wall slip surface, and the failure wedge did not form in the sand mixtures with 15 wt% and 20 wt% RCRs.
基金Funded by the Communication Science and Technology Foundation of Inner Mongolia (NJ-2005-25)
文摘A test for crumb rubber modified asphalt containing 20% crumb rubber particles（30 mesh） was performed using a scanning electron microscope（SEM）.The experimental results indicate that the crumb rubber particles are evenly distributed in the asphalt.Shear rate sweep and shear-temperature sweep tests on the crumb rubber modified asphalt at-20-80 ℃ using a dynamic shear rheology（DSR） instrument,were carried out.The tests show that the complex modulus decreases with increasing temperature;at equivalent temperature,higher load frequencies lead to a larger complex modulus,and this value increasingly decreases as the temperature increases;the phase angle increases with temperature and decreases as the load frequency increases.It can be concluded that the rutting resistance limiting temperature of crumb rubber modified asphalt is 78 ℃,and the anti-fatigue limiting temperature is 16 ℃,which shows that the asphalt has preferable rutting resistance characteristics at high temperature,as well as anti-fatigue characteristics.In addition,the complex modulus master curve at different temperatures was plotted according to the time temperature equivalence principle,which allows the study of the dynamic state behavior of crumb rubber modified asphalt at a wide range of load frequency.
基金Projects(51838001,51878070,51908069)supported by the National Natural Science Foundation of China。
文摘In this paper,organic montmorillonite(OMMT)was added into crumb rubber modified asphalt(CRMA)to improve its high temperature performance,anti-aging performance and storage stability.The effects of different OMMT content on properties of CRMA were studied.The rutting factor obtained by dynamic shear rheological(DSR)test was adopted to evaluate the high-temperature performance.The creep stiffness and m value determined by the bending beam rheometer(BBR)test were employed to evaluate the low-temperature performance.The softening point,ductility,rutting factor before and after rolling thin film ovens test(RTFOT)and pressure aging vessel test(PAV)were compared to characterize the aging properties.Moreover,the segregation test after being reserved for 48 h and 7 d was conducted,and the softening point and rutting factor of upper and lower layers of segregation pipe were adopted to evaluate the storage stability.The results indicated that the high-temperature performance and anti-aging performance were developed with the increasing content of OMMT,while the low-temperature performance deteriorated.The storage stability was improved with the increasing content of OMMT before the content exceeded 4%,after which the storage stability declined.Taking account of all factors,it is suggested that the optimum content of OMMT is 3%−4%.
文摘The microstructures of general crumb rubber(CR), dynamic desulfurized crumb rubber(DDCR) and high speed agitation desulfurized crumb rubber(HSADCR) modified bitumens were investigated by a fluorescence microscope, and the physical properties of these three modified bitumens were studied.The results show that the dynamic desulfuration can improve the swelling capacity of crumb rubber in bitumen by destroying the sulfuratized bond of the crumb rubber,but the reunion of rubber particles during dynamic desulfuration also makes the swelling and the DDCR in bitumen difficult, so properties of the DDCR modified bitumen are not superior to the general crumb rubber modified bitumen.However,high speed agitation desulfuration can not only improve the swelling capacity of crumb rubber in bitumen,but also avoid the reunion of rubber particles,so some properties of bitumen can be improved by the modification of HSADCR.
文摘In this study, the efficiency of bitumen and asphalt mixtures modified with crumb rubber(CR) and recycled glass powder(RGP) is evaluated. From an environmental point of view, the application of RGP in asphalt mixtures is considered beneficial since it prevents accumulation of waste glass in the natural environment. Rheological and mechanical properties of modified bitumen samples were investigated by laboratory methods such as bitumen conventional tests and dynamic shear rheometer(DSR), and also by asphalt mixture performance tests including Marshall stability, indirect tensile strength(ITS),compressive strength, and indirect tensile stiffness modulus. The results showed that the application of RGP in place of CR has no negative impact on the efficiency of bitumen and asphalt mixtures and even improves their engineering properties except for the toughness index(TI). Moreover, a modification with 5% CR and 5% RGP in asphalt mixtures results in the best overall performance.
文摘In this paper, properties of new kind of modified bitumen are presented. Bituminous binder was modified with mix modification using polymer and additive of crumb rubber. Terminal blend process at the refinery was applied to produce the mixed modified binder. Laboratory tests were focused on the characterization of the properties of 45/80-55 CR binder with comparison to reference 50/70 and conventional polymer modified 45/80-55 bitumen. Based on conventional binder tests such as penetration, softening point and Fraass breaking point as well as BBR （bending beam rheometer） and DSR （dynamic shear rheometer） tests, rheological properties were investigated. For determination of stability of the polymer and crumb rubber, modified bitumen tube testing method was used. Based on the results analysis, improvement of the viscoelastic properties of polymer and crumb rubber modified bitumen was observed. Conventional properties and stability tests showed that it is possible to pass standard requirements for polymer modified bitumen. Mixed modification and terminal blend allow to use crumb rubber as a modifier with elimination of the separation of crumb rubber during transportation and storage at high temperature. In this paper, experience from filed sections with use of the asphalt mixture with new kind of modified bitumen is presented.
基金Funded by Inner Mongolia Communication Technology Project (No.NJ-2005-25)
文摘Crumb rubber modified asphalt containing 20 percent crumb rubber particles of 30 mesh has been examined by Scanning Electron Microscope （SEM） to observe the microcosmic appearance and the characteristic distribution of crumb rubber particles in asphalt. The SEM pictures reveal that the crumb rubber particles distribute evenly in the asphalt and they are compatible well with asphalt. The shear creep test of crumb rubber modified asphalt was carried out at -10 ℃ and 40 ℃ by Dynamic Shear Rheology （DSR）. The shearing deformation at different temperature and creep stiffness modulus curve at loading stage of crumb rubber modified asphalt have been measured. The stiffness modulus of crumb rubber modified asphalt is much temperature sensitive and it decays much quick at the early stage of loading than normal asphalt. The rate of decay of stiffness modulus is slow at the subsequent stage and stiffness modulus approaches to a stable value at the final stage at a higher temperature. In addition, Burgers model is suitable to describe and simulate experimental results of viscoelastic properties of the crumb rubber modified asphalt.
