Rubberized concrete is one of the most studied applications of discarded tires and offers a promising approach to developing materials with enhanced properties.The rubberized concrete mixture results in a reduced modu...Rubberized concrete is one of the most studied applications of discarded tires and offers a promising approach to developing materials with enhanced properties.The rubberized concrete mixture results in a reduced modulus of elasticity and a reduced compressive and tensile strength compared to traditional concrete.This study employs finite element simulations to investigate the elastic properties of rubberized mortar(RuM),considering the influence of inclusion stiffness and interfacial debonding.Different homogenization schemes,including Voigt,Reuss,and mean-field approaches,are implemented using DIGIMAT and ANSYS.Furthermore,the influence of the interfacial transition zone(ITZ)between mortar and rubber is analyzed by periodic homogenization.Subsequently,the influence of the ITZ is examined through a linear fracture analysis with the stress intensity factor as a key parameter,using the ANSYS SMART crack growth tool.Finally,a non-linear study in FEniCS is carried out to predict the strength of the composite material through a compression test.Comparisons with high density polyethylene(HDPE)and gravel inclusions show that increasing inclusion stiffness enhances compressive strength far more effectively than simply improving the mortar/rubber bond.Indeed,when the inclusions are much softer than the surrounding matrix,any benefit gained on the elastic modulus or strength from stronger interfacial adhesion becomes almost negligible.This study provide numerical evidence that tailoring the rubber’s intrinsic stiffness—not merely strengthening the rubber/mortar interface—is a decisive factor for improving the mechanical performance of RuM.展开更多
The abrasion resistance properties of rubberized concrete were comparatively studied by taking silica fume and crumb tire rubber as the additives. The abrasion tests were conducted in accordance with the Chinese stand...The abrasion resistance properties of rubberized concrete were comparatively studied by taking silica fume and crumb tire rubber as the additives. The abrasion tests were conducted in accordance with the Chinese standard test method DL/T 5150 - 2001, two recommended test methods： under water method and ring method, were used. The crumb tire rubbers with the sieve size of 8-mesh and 16-mesh were incorporated into the concrete by replacing same volume of sand and as an additive. The abrasion resistance of concrete was evaluated according to the abrasion resistance strength and the mass loss. Test results show that the addition of silica fume enhanced both compressive strength and abrasion resistance of concrete, and the addition of crumb rubber reduced the compressive strength but increased notably the abrasion resistance of the concrete. Silica fume concrete performed a better abrasion resistance than control concrete, and the rubberized concrete performed a much better abrasion resistance than silica fume concrete. The abrasion resistance of rubberized concrete increased with the increase of rubber content.展开更多
In Greece more than 60,000 tn End of Life Tires are stockpiled every year often uncontrollable, causing severe environmental and other socio-economic negative impacts. Studies up to date are focused mainly on mechanic...In Greece more than 60,000 tn End of Life Tires are stockpiled every year often uncontrollable, causing severe environmental and other socio-economic negative impacts. Studies up to date are focused mainly on mechanical and physical characteristics of rubberized mixtures (based on cement, asphalt or soil) in which tire rubber is used either as alternative to natural aggregates or as additive. However, effect of tire rubber on noise reduction in rubberized bituminous layers, which is the main topic of present paper, has not been widely studied. In particular, this research paper is dealing with a sustainable use of tire rubber in asphalt pavement, leading to its generated noise reduction. An experimental pilot application has been conducted in the frame of a European Research Project, which has been implemented in a heavy traffic road section, cited outside Lamia city of Greece, (Vasilikon Street). The upper surface layer of the pavement has been made of rubberized bituminous mixture, produced by the wet process. Rheological characteristics of rubberized bitumen as well as basic properties of the implemented, rubberized bituminous mixture are presented. Moreover, measurements of noise level, deriving from vehicles’ motion, under operational conditions took place at the road section right after its implementation as well as after 8 months of its operation, while all data are presented in details. Results of the measurements on conventional and modified pavement sections are compared, certifying that rubberized asphalt layers can be not only environmentally friendly—since a category of solid wastes (worn automobile tires) is utilized—but also, addition of tire rubber particles in bituminous binder provides up to 3dB noise reducing bituminous mixtures and pavements, noise reduction that remains even after 8 months of road section’s operation.展开更多
To improve the combination of cement matrix and waste tire rubber particles in concrete, the rubber particles were treated with acrylic acid（ACA） and polyethylene glycol（PEG） for grafting hydrophilic groups on the...To improve the combination of cement matrix and waste tire rubber particles in concrete, the rubber particles were treated with acrylic acid（ACA） and polyethylene glycol（PEG） for grafting hydrophilic groups on their surfaces. The X-Ray photoelectron spectroscopy（XPS） and surface contact angle were used to characterize the hydrophilicity and surface functional group of rubber particles. The effect of rubber particle modifi cation on fresh/hardened properties of rubberized concrete was studied. The experimental results show that the contact angle between rubber particle surface and water decreases when rubber particle is modifi ed. Compared with the unmodifi ed rubberized concrete（RC）, the unit weight of modifi ed rubberized concrete（MRC） changes slightly. However, the slump, air-entrainment, compressive strength, flexural strength, and impact performance of MRC are obviously improved. Under good condition of slump, the water-cement ratio of the MRC can be reduced from 0.4 to 0.38. And the compressive strength and fl exural strength of the MRC（10% rubber particle content） can be increased by 25.9% and 26.4%, respectively.展开更多
Different rubber aggregates lead to changes in the effect of stress conditions on the mechanical behavior of concrete,and studies on the triaxial properties of self-compacting rubber concrete(SCRC)are rare.In this stu...Different rubber aggregates lead to changes in the effect of stress conditions on the mechanical behavior of concrete,and studies on the triaxial properties of self-compacting rubber concrete(SCRC)are rare.In this study,35 cylindrical specimens taking lateral stress and rubber type as variables were prepared to study the fresh properties and mechanical behaviors of SCRC under triaxial compression,where the rubber contains two types,i.e.,380μm rubber powder and 1–4 mm rubber particles,and four contents,i.e.,10%,20%and 30%.The test results demonstrated that SCRC exhibited a typical oblique shear failure mode under triaxial compression and had a more moderate descending branch compared with self-compacting concrete(SCC).The presence of lateral stress can significantly improve the compression properties,including initial elastic modulus,peak stress and peak strain,with an improvement range of 3%–73%for peak stress.While rubber aggregates mainly targeted the deformation abilities and toughness for improvement,and the peak strain improvement ranges were 0.1–3.1 times and 0.1–1.0 times for SCRC containing rubber powder and SCRC containing rubber particles,respectively,relative to SCC.At a high lateral stress of at least 12 MPa,the loss of strength due to the addition of rubber can be controlled within 10%,in which case the content of rubber powder and rubber particles was recommended to be at most 20%and 30%,respectively.Based on the Mohr-Coulomb theory,the failure criteria of SCRC with different rubber types were established.For analysis and design purposes,an empirical model was proposed to predict the stressstrain behavior under triaxial compression,considering the influence of different rubber content and lateral stress.The results obtained in this study can provide a valuable reference for the design and application of self-compacting rubberized concrete in practical projects,especially those involving three-way compression states and requiring high-quality deformation and energy dissipation.展开更多
The poor fatigue properties and high rigidity of cement asphalt emulsion treated mis(CETM) have for a long time been problems restricting its further development making it impossible for C-ETMto be used as surface lay...The poor fatigue properties and high rigidity of cement asphalt emulsion treated mis(CETM) have for a long time been problems restricting its further development making it impossible for C-ETMto be used as surface layer materials. In this paper, a new kind of cement asphalt emulsion composite-rubberized asphalt emulsion modified Portland cement concrete (RACC) was proposed, which was formed by dispersing rubberized aSPhalt emulsion coated coarse aggregates into cement mortar matrix. In order to evaluate systematically the performance of RACC, laboratory tests with nearly one thousand SPecimen were conducted for resilient modulus, fatigue properties, ultimate ban and length,abrasion, temperature contraction, and dry shrinkage. The experimental results show that the problems existed in C-ETM have to a great extends been solved by RACc. To verify the field performance and inquire into paving technology, teSt road appearsatlsfactory it is concluded that when thed ape surface laycr of semi-rigid base course, RACC is more for surface layer material than both Portland cement concrete(PCC) and asphalt concrete(AC)展开更多
To evaluate the effects of Crumb Rubber Modifiers (CRMS) on basic engineering properties (i.e. Marshall, tensile strength, and compressive strength) of stone matrix asphalt mixtures, the ASTM testing and procedures we...To evaluate the effects of Crumb Rubber Modifiers (CRMS) on basic engineering properties (i.e. Marshall, tensile strength, and compressive strength) of stone matrix asphalt mixtures, the ASTM testing and procedures were employed. Results of the evaluation were used to quantify the effect of CRM source and CRM content on engineering properties at testing temperatures of 25 ℃ and 60 ℃. Statistical models were developed, which represent the nature of effects on performance-related properties of stone matrix asphalt mixtures.展开更多
Concrete is among the most utilized and essential construction materials in terms of strengthening the structure.The use of natural aggregates can be reduced by using crumb rubber aggregates(RA)as a substitute.The use...Concrete is among the most utilized and essential construction materials in terms of strengthening the structure.The use of natural aggregates can be reduced by using crumb rubber aggregates(RA)as a substitute.The use of RA will reduce the expense on aggregate and help in creating a sustainable environment.Nanoparticles improve the microscopic structure of concrete by filling pores present in cement paste thus reducing the cement usage in the mix.Employing nano titanium dioxide(NT)in rubber concrete(RC)helps to improve its properties.The findings showed that RA significantly alters the characteristics of the concrete;at a 15%level of fine aggregate(FA)replacement,the workability and density of the concrete mixes dropped by up to 26.53%and 5%,respectively.Concrete's compressive,tensile,and flexural strengths decreased by 16.1%,5.52%,and 3.1%,respectively,as a result of adding RA.However,these negative effects were successfully offset by the addition of NT.Even while workability declined,density grew.The research shows that the use of NT in RC composites enhances corrosion resistance and durability,reduces porosity,and improves permeability.The research also suggests that NT helps to smoothen pores and microcracks in concrete,resulting in enhanced resistance to elements such as water and air.This study employs analysis of variance to evaluate the mechanical and durability characteristics of rubberized concrete composites.Microstructural investigation employing field emission scanning electron microscopy examines the interfacial transition zone,hydration products,and pore structure,offering insights into the influence of NT on concrete matrix.This study offers thorough,significant information on the application of NT nanoparticles as a green and efficient additive to enhance concrete performance,and it also presents potential for additional studies in this area of study.展开更多
Recently developed multi-scale fiber(i.e.,CaCO3 whisker,polyvinyl alcohol(PVA)fiber,and steel fiber)reinforced rubberized concrete exhibits excellent mechanical properties and spalling resistance at high temperatures....Recently developed multi-scale fiber(i.e.,CaCO3 whisker,polyvinyl alcohol(PVA)fiber,and steel fiber)reinforced rubberized concrete exhibits excellent mechanical properties and spalling resistance at high temperatures.Measurement of macro properties such as strength and Young’s modulus cannot reveal and characterize damage mechanisms,particularly those relating to the multi-scale fiber strengthening effect.In this study,acoustic emission(AE)technology is applied to investigate the impact of multi-scale fiber on the damage evolution of rubberized concrete exposed to high temperatures,under the uniaxial compression and tension loading processes.The mechanical properties,AE event location,peak frequency,b-value,the ratio of rise time to amplitude(RA),average frequency(AF)values,and AE energy of specimens are investigated.The results show that the number of events observed using AE gradually increases as the loading progresses.The crumb rubber and fibers inhibit the generation and development of the cracks.It is concluded that both the peak frequency and b-value reflect the extension process of cracks.As the cracks develop from the micro scale to the macro scale,the peak frequency tends to be distributed in a lower frequency range,and the b-value decreases gradually.At the peak stress point,the AE energy increases rapidly and the b-value decreases.The specimens without multi-scale fibers exhibit brittle failure,while the specimens with fibers exhibit ductile failure.In addition,adding multi-scale fibers and crumb rubber increases the peak frequency in the medium and high frequency ranges,indicating a positive effect on inhibiting crack development.After being subjected to high temperatures,the maximum and minimum b-values decrease,reflecting an increase in the number of initial cracks due to thermal damage.Meanwhile,the RA and AF values are used to classify tensile and shear cracks.The specimens fracture with more shear cracks under compression,and there are more tensile cracks in specimens with multi-scale fibers under tension.展开更多
Acoustic emission (AE) technique is employed to investigate the damage process of the notched plain concrete and rubberized concrete specimens under 3-point bending load.AE signals in the fracture process of notched s...Acoustic emission (AE) technique is employed to investigate the damage process of the notched plain concrete and rubberized concrete specimens under 3-point bending load.AE signals in the fracture process of notched specimens are illustrated by analyzing the distribution of amplitude and hit rate of AE signals.AE signals in the rubberized concrete have lower activity and amplitude than in the plain concrete.By AE location analysis,it is found that the high energy events mainly are distributed near the notch tip.According to AE energy,the fracture process zone (FPZ) is determined.By comparing the FPZ of both concretes,it is found that the incorporation of rubber particles in concrete can greatly alleviate the damage process of concrete specimens and the damage zone in the rubberized concrete is much smaller than in the plain concrete.The moment tensor is also used to analyze the type of cracks and it is found that tensile cracks dominate the early period of loading,while shear cracks become dominant with propagation of cracks in late load period.展开更多
The study presents an experimental evaluation of performance properties of two different production processes of warm rubberized binder.Two types of rubberized binder were produced through dry process and wet process ...The study presents an experimental evaluation of performance properties of two different production processes of warm rubberized binder.Two types of rubberized binder were produced through dry process and wet process and two of the available wax additives were added into the rubberized binders(i.e.,LEADCAP and Sasobit).Rubberized binders with wax additives were artificially short-term and long-term aged using the rolling thin film oven(RTFO) and pressure aging vessel(PAV) procedures.Superpave binder tests were carried out on the binders through the rotational viscometer(RV),the dynamic shear rheometer(DSR),and the bending beam rheometer(BBR).In general,the results of this study indicated that(1) the viscosity properties have been found to be similar between dry and wet processes,(2) the rubberized binders manufactured by wet process were observed to have the higher rutting resistance than those by dry process,(3) the wet process resulted in better performance in the fatigue cracking test than the dry process,and(4) the blending method was found to have little influence of stiffness properties.展开更多
Silicone rubber(SR)is a versatile material widely used across various advanced functional applications,such as soft actuators and robots,flexible electronics,and medical devices.However,most SR molding methods rely on...Silicone rubber(SR)is a versatile material widely used across various advanced functional applications,such as soft actuators and robots,flexible electronics,and medical devices.However,most SR molding methods rely on traditional thermal processing or direct ink writing three-dimensional(3D)printing.These methods are not conducive to manufacturing complex structures and present challenges such as time inefficiency,poor accuracy,and the necessity of multiple steps,significantly limiting SR applications.In this study,we developed an SR-based ink suitable for vat photopolymerization 3D printing using a multi-thiol monomer.This ink enables the one-step fabrication of complex architectures with high printing resolution at the micrometer scale,providing excellent mechanical strength and superior chemical stability.Specifically,the optimized 3D printing SR-20 exhibits a tensile stress of 1.96 MPa,an elongation at break of 487.9%,and an elastic modulus of 225.4 kPa.Additionally,the 3D-printed SR samples can withstand various solvents(acetone,toluene,and tetrahydrofuran)and endure temperatures ranging from-50℃ to 180℃,demonstrating superior stability.As a emonstration of the application,we successfully fabricated a series of SR-based soft pneumatic actuators and grippers in a single step with this technology,allowing for free assembly for the first time.This ultraviolet-curable SR,with high printing resolution and exceptional stability performance,has significant potential to enhance the capabilities of 3D printing for applications in soft actuators,robotics,flexible electronics,and medical devices.展开更多
The predictive model and design of heavy-duty metal rubber shock absorber for the powertrains of heavy-load mining vehicles were investigated.The microstructural characteristics of the wire mesh were elucidated using ...The predictive model and design of heavy-duty metal rubber shock absorber for the powertrains of heavy-load mining vehicles were investigated.The microstructural characteristics of the wire mesh were elucidated using fractal graphs.A numerical model based on virtual fabrication technique was established to propose a design scheme for the wire mesh component.Four sets of wire mesh shock absorbers with various relative densities were prepared and a predictive model based on these relative densities was established through mechanical testing.To further enhance the predictive accuracy,a variable transposition fitting method was proposed to refine the model.Residual analysis was employed to quantitatively validate the results against those obtained from an experimental control group.The results show that the improved model exhibits higher predictive accuracy than the original model,with the determination coefficient(R^(2))of 0.9624.This study provides theoretical support for designing wire mesh shock absorbers with reduced testing requirements and enhanced design efficiency.展开更多
The flocculation behavior of carbon black (CB)-filled isoprene rubber (IR) nanocomposites was systematically investigated under both dynamic and static conditions to unravel the distinct mechanisms governing filler ne...The flocculation behavior of carbon black (CB)-filled isoprene rubber (IR) nanocomposites was systematically investigated under both dynamic and static conditions to unravel the distinct mechanisms governing filler network evolution.Under dynamic conditions,small oscillatory shear strains (0.1%) significantly enhanced filler particle motion,leading to pronounced agglomeration and a flocculation degree of about 4.3MPa at 145℃.In contrast,static flocculation exhibited a fundamentally different mechanism dominated by polymer chain dynamics,which is driven mainly by thermal activation.Radial distribution function (RDF) analysis of transmission electron microscopy (TEM) images revealed a slight decrease (2 nm) in the interparticle distance peak after static annealing at 100℃ for 7 h,indicating localized motion of CB particles.However,the overall filler network remained stable,with no significant agglomeration observed.The increase in bound rubber content from about 23% to 28% with rising temperature further confirmed the dominant role of polymer chain adsorption and interfacial reinforcement in static flocculation.These findings highlight the critical influence of external strain on filler network formation and provide new insights into the polymer-dominated mechanism of static flocculation.The results offer practical guidance for optimizing the storage and processing of rubber nanocomposites,particularly in applications where static flocculation during prolonged storage is a concern.展开更多
Immunosuppressed patients have increased susceptibility to various infections,including opportunistic infections.The risk of infective complications in these patients is significantly higher,which can lead to more sev...Immunosuppressed patients have increased susceptibility to various infections,including opportunistic infections.The risk of infective complications in these patients is significantly higher,which can lead to more severe infections,prolonged illness course,and an increased likelihood of poor outcome,including sepsis,organ failure,and even death.Blue rubber bleb nevus syndrome(BRBNS)is a rare syndrome characterized by venous malformations primarily found in the skin and gastrointestinal(GI)tract.展开更多
Title:Seismic fragility of unreinforced masonry buildings with bonded scrap tire rubber isolators under far-field and near-field earthquakes Authors:WANG Mingyang;GAO Wenjun;LU Xilin;SHI Weixing A bstract:To improve t...Title:Seismic fragility of unreinforced masonry buildings with bonded scrap tire rubber isolators under far-field and near-field earthquakes Authors:WANG Mingyang;GAO Wenjun;LU Xilin;SHI Weixing A bstract:To improve the seismic performance of unreinforced masonry(URM)buildings in the Himalayan regions,including Western China,India,Nepal,and Pakistan,a low-cost bonded scrap tire rubber isolator(BSTRI)is proposed,and a series of vertical compression and horizontal shear tests are conducted.Incremental dynamic analyses are conducted for five types of BSTRI-supported URM buildings subjected to 22 far-field and 28 near-field earthquake ground motions.The resulting fragility curves and probability of damage curves are presented and utilized to evaluate the damage states of these buildings.The results show that in the base-isolated(BI)URM buildings under seismic ground motion at a peak ground acceleration(PGA)of 1.102 g,the probability of exceeding the collapse prevention threshold is less than 25%under far-field earthquake ground motions and 31%under near-field earthquake ground motions.Furthermore,the maximum average vulnerability index for the BI-URM buildings,which are designed to withstand rare earthquakes with 9°(PGA=0.632 g),is 40.87%for far-field earthquake ground motions and 41.83%for near-field earthquake ground motions.Therefore,the adoption of BSTRIs can significantly reduce the collapse probability of URM buildings.展开更多
Rubbery waste at the end of the cycle often constitutes a threat for the environment because of their encumbrance and low biodeterioration.The purpose of the research presented is to develop the rubber fine powder as ...Rubbery waste at the end of the cycle often constitutes a threat for the environment because of their encumbrance and low biodeterioration.The purpose of the research presented is to develop the rubber fine powder as a pavement.It is interested primarily in the behavior of two types of bitumen 40/50 modified by the addition of two varieties of rubber fine powders of different grading,resulting from the crushing of the rubbery products intended for the clothes industry of soles of shoes.The objective of the experimentation is to study the influence of the added polymer on the physical properties of the ordinary road bitumen with the incorporation of the fine powder.The experimental approach is carried out using the two tests of characterization of the bitumen i.e.the softening point test and the penetration test which remain the most used to define and classify the road bitumen.It will be noted however,that the experimental investigation which is based on several tests according to the type and the content of fine powders,leads on a whole of interesting correlations.展开更多
The ongoing operation of subway systems makes existing tunnels vulnerable to deformations and structural damage caused by adjacent foundation pit construction.Such deformations-manifesting as horizontal displacement,h...The ongoing operation of subway systems makes existing tunnels vulnerable to deformations and structural damage caused by adjacent foundation pit construction.Such deformations-manifesting as horizontal displacement,heightened lateral convergence,and internal force redistribution-may significantly compromise subway operational safety.Grouting remediation has become a widely adopted solution for tunnel deformation control and structural reinforcement.Developing optimized grouting materials is crucial for improving remediation effectiveness,ensuring structural integrity,and maintaining uninterrupted subway operations.This investigation explores the substitution of fine mortar aggregates with 0.1 mm discarded rubber particles at varying concentrations(0%,3%,6%,9%,12%,and 15%).Experimental parameters included three water-cement ratios(0.65,0.70,and 0.75)with constant 4%WPU content.Mechanical properties including compressive strength,flexural strength,and compression-to-bending ratio were evaluated across specified curing periods.Material characterization employed Fourier Transform Infrared Spectroscopy(FTIR)spectroscopy for molecular analysis and Scanning Electron Microscopy(SEM)for microstructural examination.Results indicate optimal toughness at 0.70 water-cement ratio with 6%rubber content,meeting mechanical pumping specifications while maintaining structural performance.展开更多
Biti’s is one of the largest footwear manufacturers in Vietnam.Made from homegrown high-quality natural rubber,Biti’s slippers are known for their slip-resistance,durability,lightness,and breathability.In addition t...Biti’s is one of the largest footwear manufacturers in Vietnam.Made from homegrown high-quality natural rubber,Biti’s slippers are known for their slip-resistance,durability,lightness,and breathability.In addition to practicality and comfort,the products come in diverse styles at affordable prices.展开更多
The thioacetamide derivative(TD)-composite preservation system(TDCPS)exhibits superior preservation effects on natural rubber latex(NRL)and significantly enhances its vulcanization efficiency and mechanical properties...The thioacetamide derivative(TD)-composite preservation system(TDCPS)exhibits superior preservation effects on natural rubber latex(NRL)and significantly enhances its vulcanization efficiency and mechanical properties.This study primarily investigated the principal chemical groups and mechanism of action of TDCPS in promoting NRL vulcanization through a comparative analysis.The results indicated that the key functional groups(thioamide and pyridine)in TDCPS synergistically accelerated crosslinking,reducing the vulcanization time by 41.18%compared to the high-ammonia(HA)preservation system.At an optimal TDCPS dosage of 5 mmol·L^(−1),vulcanized films achieved a tensile strength of 34.18 MPa,with a sulfur content of 1.5 phr further improving the strength by 42.26%.TD outperformed the conventional accelerators 2-imidazolidinethione(ETU)and 3-hydroxypyridine(3-Hp)in promoting the crosslinking density and mechanical performance while eliminating ammonia-related environmental risks.This eco-friendly system demonstrates the industrial potential for sustainable rubber production.展开更多
基金financial support from the Chilean National Agency for Research and Development(ANID),National Doctorate No.21212028financial support from ANID,FONDECYT Regular Research Project No.1221793.
文摘Rubberized concrete is one of the most studied applications of discarded tires and offers a promising approach to developing materials with enhanced properties.The rubberized concrete mixture results in a reduced modulus of elasticity and a reduced compressive and tensile strength compared to traditional concrete.This study employs finite element simulations to investigate the elastic properties of rubberized mortar(RuM),considering the influence of inclusion stiffness and interfacial debonding.Different homogenization schemes,including Voigt,Reuss,and mean-field approaches,are implemented using DIGIMAT and ANSYS.Furthermore,the influence of the interfacial transition zone(ITZ)between mortar and rubber is analyzed by periodic homogenization.Subsequently,the influence of the ITZ is examined through a linear fracture analysis with the stress intensity factor as a key parameter,using the ANSYS SMART crack growth tool.Finally,a non-linear study in FEniCS is carried out to predict the strength of the composite material through a compression test.Comparisons with high density polyethylene(HDPE)and gravel inclusions show that increasing inclusion stiffness enhances compressive strength far more effectively than simply improving the mortar/rubber bond.Indeed,when the inclusions are much softer than the surrounding matrix,any benefit gained on the elastic modulus or strength from stronger interfacial adhesion becomes almost negligible.This study provide numerical evidence that tailoring the rubber’s intrinsic stiffness—not merely strengthening the rubber/mortar interface—is a decisive factor for improving the mechanical performance of RuM.
基金Funded by the National Natural Science Foundation of China(50979068)
文摘The abrasion resistance properties of rubberized concrete were comparatively studied by taking silica fume and crumb tire rubber as the additives. The abrasion tests were conducted in accordance with the Chinese standard test method DL/T 5150 - 2001, two recommended test methods： under water method and ring method, were used. The crumb tire rubbers with the sieve size of 8-mesh and 16-mesh were incorporated into the concrete by replacing same volume of sand and as an additive. The abrasion resistance of concrete was evaluated according to the abrasion resistance strength and the mass loss. Test results show that the addition of silica fume enhanced both compressive strength and abrasion resistance of concrete, and the addition of crumb rubber reduced the compressive strength but increased notably the abrasion resistance of the concrete. Silica fume concrete performed a better abrasion resistance than control concrete, and the rubberized concrete performed a much better abrasion resistance than silica fume concrete. The abrasion resistance of rubberized concrete increased with the increase of rubber content.
文摘In Greece more than 60,000 tn End of Life Tires are stockpiled every year often uncontrollable, causing severe environmental and other socio-economic negative impacts. Studies up to date are focused mainly on mechanical and physical characteristics of rubberized mixtures (based on cement, asphalt or soil) in which tire rubber is used either as alternative to natural aggregates or as additive. However, effect of tire rubber on noise reduction in rubberized bituminous layers, which is the main topic of present paper, has not been widely studied. In particular, this research paper is dealing with a sustainable use of tire rubber in asphalt pavement, leading to its generated noise reduction. An experimental pilot application has been conducted in the frame of a European Research Project, which has been implemented in a heavy traffic road section, cited outside Lamia city of Greece, (Vasilikon Street). The upper surface layer of the pavement has been made of rubberized bituminous mixture, produced by the wet process. Rheological characteristics of rubberized bitumen as well as basic properties of the implemented, rubberized bituminous mixture are presented. Moreover, measurements of noise level, deriving from vehicles’ motion, under operational conditions took place at the road section right after its implementation as well as after 8 months of its operation, while all data are presented in details. Results of the measurements on conventional and modified pavement sections are compared, certifying that rubberized asphalt layers can be not only environmentally friendly—since a category of solid wastes (worn automobile tires) is utilized—but also, addition of tire rubber particles in bituminous binder provides up to 3dB noise reducing bituminous mixtures and pavements, noise reduction that remains even after 8 months of road section’s operation.
基金Funded by the National Natural Science Foundation of China(U1204513)the Programs for Science and Technology Development of Henan Province(132102310032)
文摘To improve the combination of cement matrix and waste tire rubber particles in concrete, the rubber particles were treated with acrylic acid（ACA） and polyethylene glycol（PEG） for grafting hydrophilic groups on their surfaces. The X-Ray photoelectron spectroscopy（XPS） and surface contact angle were used to characterize the hydrophilicity and surface functional group of rubber particles. The effect of rubber particle modifi cation on fresh/hardened properties of rubberized concrete was studied. The experimental results show that the contact angle between rubber particle surface and water decreases when rubber particle is modifi ed. Compared with the unmodifi ed rubberized concrete（RC）, the unit weight of modifi ed rubberized concrete（MRC） changes slightly. However, the slump, air-entrainment, compressive strength, flexural strength, and impact performance of MRC are obviously improved. Under good condition of slump, the water-cement ratio of the MRC can be reduced from 0.4 to 0.38. And the compressive strength and fl exural strength of the MRC（10% rubber particle content） can be increased by 25.9% and 26.4%, respectively.
基金supported by National Natural Science Foundation of China(Project No.51468003)Natural Science Foundation of Guangxi Province(Project No.2018GXNSFAA050007).
文摘Different rubber aggregates lead to changes in the effect of stress conditions on the mechanical behavior of concrete,and studies on the triaxial properties of self-compacting rubber concrete(SCRC)are rare.In this study,35 cylindrical specimens taking lateral stress and rubber type as variables were prepared to study the fresh properties and mechanical behaviors of SCRC under triaxial compression,where the rubber contains two types,i.e.,380μm rubber powder and 1–4 mm rubber particles,and four contents,i.e.,10%,20%and 30%.The test results demonstrated that SCRC exhibited a typical oblique shear failure mode under triaxial compression and had a more moderate descending branch compared with self-compacting concrete(SCC).The presence of lateral stress can significantly improve the compression properties,including initial elastic modulus,peak stress and peak strain,with an improvement range of 3%–73%for peak stress.While rubber aggregates mainly targeted the deformation abilities and toughness for improvement,and the peak strain improvement ranges were 0.1–3.1 times and 0.1–1.0 times for SCRC containing rubber powder and SCRC containing rubber particles,respectively,relative to SCC.At a high lateral stress of at least 12 MPa,the loss of strength due to the addition of rubber can be controlled within 10%,in which case the content of rubber powder and rubber particles was recommended to be at most 20%and 30%,respectively.Based on the Mohr-Coulomb theory,the failure criteria of SCRC with different rubber types were established.For analysis and design purposes,an empirical model was proposed to predict the stressstrain behavior under triaxial compression,considering the influence of different rubber content and lateral stress.The results obtained in this study can provide a valuable reference for the design and application of self-compacting rubberized concrete in practical projects,especially those involving three-way compression states and requiring high-quality deformation and energy dissipation.
文摘The poor fatigue properties and high rigidity of cement asphalt emulsion treated mis(CETM) have for a long time been problems restricting its further development making it impossible for C-ETMto be used as surface layer materials. In this paper, a new kind of cement asphalt emulsion composite-rubberized asphalt emulsion modified Portland cement concrete (RACC) was proposed, which was formed by dispersing rubberized aSPhalt emulsion coated coarse aggregates into cement mortar matrix. In order to evaluate systematically the performance of RACC, laboratory tests with nearly one thousand SPecimen were conducted for resilient modulus, fatigue properties, ultimate ban and length,abrasion, temperature contraction, and dry shrinkage. The experimental results show that the problems existed in C-ETM have to a great extends been solved by RACc. To verify the field performance and inquire into paving technology, teSt road appearsatlsfactory it is concluded that when thed ape surface laycr of semi-rigid base course, RACC is more for surface layer material than both Portland cement concrete(PCC) and asphalt concrete(AC)
文摘To evaluate the effects of Crumb Rubber Modifiers (CRMS) on basic engineering properties (i.e. Marshall, tensile strength, and compressive strength) of stone matrix asphalt mixtures, the ASTM testing and procedures were employed. Results of the evaluation were used to quantify the effect of CRM source and CRM content on engineering properties at testing temperatures of 25 ℃ and 60 ℃. Statistical models were developed, which represent the nature of effects on performance-related properties of stone matrix asphalt mixtures.
文摘Concrete is among the most utilized and essential construction materials in terms of strengthening the structure.The use of natural aggregates can be reduced by using crumb rubber aggregates(RA)as a substitute.The use of RA will reduce the expense on aggregate and help in creating a sustainable environment.Nanoparticles improve the microscopic structure of concrete by filling pores present in cement paste thus reducing the cement usage in the mix.Employing nano titanium dioxide(NT)in rubber concrete(RC)helps to improve its properties.The findings showed that RA significantly alters the characteristics of the concrete;at a 15%level of fine aggregate(FA)replacement,the workability and density of the concrete mixes dropped by up to 26.53%and 5%,respectively.Concrete's compressive,tensile,and flexural strengths decreased by 16.1%,5.52%,and 3.1%,respectively,as a result of adding RA.However,these negative effects were successfully offset by the addition of NT.Even while workability declined,density grew.The research shows that the use of NT in RC composites enhances corrosion resistance and durability,reduces porosity,and improves permeability.The research also suggests that NT helps to smoothen pores and microcracks in concrete,resulting in enhanced resistance to elements such as water and air.This study employs analysis of variance to evaluate the mechanical and durability characteristics of rubberized concrete composites.Microstructural investigation employing field emission scanning electron microscopy examines the interfacial transition zone,hydration products,and pore structure,offering insights into the influence of NT on concrete matrix.This study offers thorough,significant information on the application of NT nanoparticles as a green and efficient additive to enhance concrete performance,and it also presents potential for additional studies in this area of study.
基金supported by the National Natural Science Foundation of China(Grant No.52108379)the Natural Science Foundation of Hebei Province(No.E2021210002)+3 种基金the Youth Top Talent Program,Education Department of Hebei Province(No.BJK2022047)Innovation Research Group Program of Natural Science,the Hebei Province(No.E2021210099)the Technology Development Project of Shuohuang Railway Development Co.,Ltd.(No.GJNY-20-230)the Innovation Research for the Postgraduates of Shijiazhuang Tiedao University(No.YC2023009).
文摘Recently developed multi-scale fiber(i.e.,CaCO3 whisker,polyvinyl alcohol(PVA)fiber,and steel fiber)reinforced rubberized concrete exhibits excellent mechanical properties and spalling resistance at high temperatures.Measurement of macro properties such as strength and Young’s modulus cannot reveal and characterize damage mechanisms,particularly those relating to the multi-scale fiber strengthening effect.In this study,acoustic emission(AE)technology is applied to investigate the impact of multi-scale fiber on the damage evolution of rubberized concrete exposed to high temperatures,under the uniaxial compression and tension loading processes.The mechanical properties,AE event location,peak frequency,b-value,the ratio of rise time to amplitude(RA),average frequency(AF)values,and AE energy of specimens are investigated.The results show that the number of events observed using AE gradually increases as the loading progresses.The crumb rubber and fibers inhibit the generation and development of the cracks.It is concluded that both the peak frequency and b-value reflect the extension process of cracks.As the cracks develop from the micro scale to the macro scale,the peak frequency tends to be distributed in a lower frequency range,and the b-value decreases gradually.At the peak stress point,the AE energy increases rapidly and the b-value decreases.The specimens without multi-scale fibers exhibit brittle failure,while the specimens with fibers exhibit ductile failure.In addition,adding multi-scale fibers and crumb rubber increases the peak frequency in the medium and high frequency ranges,indicating a positive effect on inhibiting crack development.After being subjected to high temperatures,the maximum and minimum b-values decrease,reflecting an increase in the number of initial cracks due to thermal damage.Meanwhile,the RA and AF values are used to classify tensile and shear cracks.The specimens fracture with more shear cracks under compression,and there are more tensile cracks in specimens with multi-scale fibers under tension.
基金supported by the National Basic Research Program of China (973 Program) (Grant No.2009CB623200)National Natural Science Foundation of China (Grant No.50778039)
文摘Acoustic emission (AE) technique is employed to investigate the damage process of the notched plain concrete and rubberized concrete specimens under 3-point bending load.AE signals in the fracture process of notched specimens are illustrated by analyzing the distribution of amplitude and hit rate of AE signals.AE signals in the rubberized concrete have lower activity and amplitude than in the plain concrete.By AE location analysis,it is found that the high energy events mainly are distributed near the notch tip.According to AE energy,the fracture process zone (FPZ) is determined.By comparing the FPZ of both concretes,it is found that the incorporation of rubber particles in concrete can greatly alleviate the damage process of concrete specimens and the damage zone in the rubberized concrete is much smaller than in the plain concrete.The moment tensor is also used to analyze the type of cracks and it is found that tensile cracks dominate the early period of loading,while shear cracks become dominant with propagation of cracks in late load period.
基金supported by the Research Grant from KICT through the Korea Agency for Infrastructure Technology Advancement funded by the Ministry of Land,Infrastructure and Transport of the Korean Government (Project No:18TBIP6125410-02).
文摘The study presents an experimental evaluation of performance properties of two different production processes of warm rubberized binder.Two types of rubberized binder were produced through dry process and wet process and two of the available wax additives were added into the rubberized binders(i.e.,LEADCAP and Sasobit).Rubberized binders with wax additives were artificially short-term and long-term aged using the rolling thin film oven(RTFO) and pressure aging vessel(PAV) procedures.Superpave binder tests were carried out on the binders through the rotational viscometer(RV),the dynamic shear rheometer(DSR),and the bending beam rheometer(BBR).In general,the results of this study indicated that(1) the viscosity properties have been found to be similar between dry and wet processes,(2) the rubberized binders manufactured by wet process were observed to have the higher rutting resistance than those by dry process,(3) the wet process resulted in better performance in the fatigue cracking test than the dry process,and(4) the blending method was found to have little influence of stiffness properties.
基金supported by the Strategic Priority Program of the Chinese Academy of Sciences(XDB0470303)the National Key R&D Program of China(2022YFB4600102and 2023YFE0209900)+4 种基金the National Natural Science Foundation of China(52175201 and 51935012)the science and technology projects of Gansu province(22JR5RA093,24JRRA044,24YFFA014 and 24ZDGA014)the Innovation and Entrepreneurship Team Project of YEDA(2021TD007)the special supporting project for provincial leading talents of Yantaithe Taishan Scholars Program。
文摘Silicone rubber(SR)is a versatile material widely used across various advanced functional applications,such as soft actuators and robots,flexible electronics,and medical devices.However,most SR molding methods rely on traditional thermal processing or direct ink writing three-dimensional(3D)printing.These methods are not conducive to manufacturing complex structures and present challenges such as time inefficiency,poor accuracy,and the necessity of multiple steps,significantly limiting SR applications.In this study,we developed an SR-based ink suitable for vat photopolymerization 3D printing using a multi-thiol monomer.This ink enables the one-step fabrication of complex architectures with high printing resolution at the micrometer scale,providing excellent mechanical strength and superior chemical stability.Specifically,the optimized 3D printing SR-20 exhibits a tensile stress of 1.96 MPa,an elongation at break of 487.9%,and an elastic modulus of 225.4 kPa.Additionally,the 3D-printed SR samples can withstand various solvents(acetone,toluene,and tetrahydrofuran)and endure temperatures ranging from-50℃ to 180℃,demonstrating superior stability.As a emonstration of the application,we successfully fabricated a series of SR-based soft pneumatic actuators and grippers in a single step with this technology,allowing for free assembly for the first time.This ultraviolet-curable SR,with high printing resolution and exceptional stability performance,has significant potential to enhance the capabilities of 3D printing for applications in soft actuators,robotics,flexible electronics,and medical devices.
基金National Natural Science Foundation of China(12262028)Program for Young Talents of Science and Technology in Universities of Inner Mongolia Autonomous Region(NJYT22085)Inner Mongolia Autonomous Region Science and Technology Plan Project(2021GG0437)。
文摘The predictive model and design of heavy-duty metal rubber shock absorber for the powertrains of heavy-load mining vehicles were investigated.The microstructural characteristics of the wire mesh were elucidated using fractal graphs.A numerical model based on virtual fabrication technique was established to propose a design scheme for the wire mesh component.Four sets of wire mesh shock absorbers with various relative densities were prepared and a predictive model based on these relative densities was established through mechanical testing.To further enhance the predictive accuracy,a variable transposition fitting method was proposed to refine the model.Residual analysis was employed to quantitatively validate the results against those obtained from an experimental control group.The results show that the improved model exhibits higher predictive accuracy than the original model,with the determination coefficient(R^(2))of 0.9624.This study provides theoretical support for designing wire mesh shock absorbers with reduced testing requirements and enhanced design efficiency.
基金supported by the National Natural Science Foundation of China(No.52293471)National Key R&D Program of China(No.2022YFB3707303).
文摘The flocculation behavior of carbon black (CB)-filled isoprene rubber (IR) nanocomposites was systematically investigated under both dynamic and static conditions to unravel the distinct mechanisms governing filler network evolution.Under dynamic conditions,small oscillatory shear strains (0.1%) significantly enhanced filler particle motion,leading to pronounced agglomeration and a flocculation degree of about 4.3MPa at 145℃.In contrast,static flocculation exhibited a fundamentally different mechanism dominated by polymer chain dynamics,which is driven mainly by thermal activation.Radial distribution function (RDF) analysis of transmission electron microscopy (TEM) images revealed a slight decrease (2 nm) in the interparticle distance peak after static annealing at 100℃ for 7 h,indicating localized motion of CB particles.However,the overall filler network remained stable,with no significant agglomeration observed.The increase in bound rubber content from about 23% to 28% with rising temperature further confirmed the dominant role of polymer chain adsorption and interfacial reinforcement in static flocculation.These findings highlight the critical influence of external strain on filler network formation and provide new insights into the polymer-dominated mechanism of static flocculation.The results offer practical guidance for optimizing the storage and processing of rubber nanocomposites,particularly in applications where static flocculation during prolonged storage is a concern.
基金funded by Tianjin Key Medical Discipline(Specialty)Construction Project(TJYXZDXK-007A).
文摘Immunosuppressed patients have increased susceptibility to various infections,including opportunistic infections.The risk of infective complications in these patients is significantly higher,which can lead to more severe infections,prolonged illness course,and an increased likelihood of poor outcome,including sepsis,organ failure,and even death.Blue rubber bleb nevus syndrome(BRBNS)is a rare syndrome characterized by venous malformations primarily found in the skin and gastrointestinal(GI)tract.
文摘Title:Seismic fragility of unreinforced masonry buildings with bonded scrap tire rubber isolators under far-field and near-field earthquakes Authors:WANG Mingyang;GAO Wenjun;LU Xilin;SHI Weixing A bstract:To improve the seismic performance of unreinforced masonry(URM)buildings in the Himalayan regions,including Western China,India,Nepal,and Pakistan,a low-cost bonded scrap tire rubber isolator(BSTRI)is proposed,and a series of vertical compression and horizontal shear tests are conducted.Incremental dynamic analyses are conducted for five types of BSTRI-supported URM buildings subjected to 22 far-field and 28 near-field earthquake ground motions.The resulting fragility curves and probability of damage curves are presented and utilized to evaluate the damage states of these buildings.The results show that in the base-isolated(BI)URM buildings under seismic ground motion at a peak ground acceleration(PGA)of 1.102 g,the probability of exceeding the collapse prevention threshold is less than 25%under far-field earthquake ground motions and 31%under near-field earthquake ground motions.Furthermore,the maximum average vulnerability index for the BI-URM buildings,which are designed to withstand rare earthquakes with 9°(PGA=0.632 g),is 40.87%for far-field earthquake ground motions and 41.83%for near-field earthquake ground motions.Therefore,the adoption of BSTRIs can significantly reduce the collapse probability of URM buildings.
文摘Rubbery waste at the end of the cycle often constitutes a threat for the environment because of their encumbrance and low biodeterioration.The purpose of the research presented is to develop the rubber fine powder as a pavement.It is interested primarily in the behavior of two types of bitumen 40/50 modified by the addition of two varieties of rubber fine powders of different grading,resulting from the crushing of the rubbery products intended for the clothes industry of soles of shoes.The objective of the experimentation is to study the influence of the added polymer on the physical properties of the ordinary road bitumen with the incorporation of the fine powder.The experimental approach is carried out using the two tests of characterization of the bitumen i.e.the softening point test and the penetration test which remain the most used to define and classify the road bitumen.It will be noted however,that the experimental investigation which is based on several tests according to the type and the content of fine powders,leads on a whole of interesting correlations.
基金supported by the National Natural Science Foundation of China,Grant Nos.42477185,41602308the Zhejiang Provincial Natural Science Foundation of China,Grant No.LY20E080005+2 种基金the Zhejiang Province University Students Science and Technology Innovation Program,Grant No.0201310P28the PostGraduate Course Construction Project of Zhejiang University of Science and Technology,Grant No.2021yjskj05the Zhejiang University of Science and Technology Graduate Research and Innovation Fund,Grant No.2023yjskc10.
文摘The ongoing operation of subway systems makes existing tunnels vulnerable to deformations and structural damage caused by adjacent foundation pit construction.Such deformations-manifesting as horizontal displacement,heightened lateral convergence,and internal force redistribution-may significantly compromise subway operational safety.Grouting remediation has become a widely adopted solution for tunnel deformation control and structural reinforcement.Developing optimized grouting materials is crucial for improving remediation effectiveness,ensuring structural integrity,and maintaining uninterrupted subway operations.This investigation explores the substitution of fine mortar aggregates with 0.1 mm discarded rubber particles at varying concentrations(0%,3%,6%,9%,12%,and 15%).Experimental parameters included three water-cement ratios(0.65,0.70,and 0.75)with constant 4%WPU content.Mechanical properties including compressive strength,flexural strength,and compression-to-bending ratio were evaluated across specified curing periods.Material characterization employed Fourier Transform Infrared Spectroscopy(FTIR)spectroscopy for molecular analysis and Scanning Electron Microscopy(SEM)for microstructural examination.Results indicate optimal toughness at 0.70 water-cement ratio with 6%rubber content,meeting mechanical pumping specifications while maintaining structural performance.
文摘Biti’s is one of the largest footwear manufacturers in Vietnam.Made from homegrown high-quality natural rubber,Biti’s slippers are known for their slip-resistance,durability,lightness,and breathability.In addition to practicality and comfort,the products come in diverse styles at affordable prices.
基金the Ministry of Agriculture and Rural Affairs of Chinathe Department of Science and Technology of the Hainan Province for their support+2 种基金financially supported by the National Key R&D Program of China(No. 2022YFD2301201)Hainan Province Science and Technology Special Fund (No. ZDYF2024XDNY284)Earmarked Fund for China Agriculture Research System (No.CARS-33-JG1)
文摘The thioacetamide derivative(TD)-composite preservation system(TDCPS)exhibits superior preservation effects on natural rubber latex(NRL)and significantly enhances its vulcanization efficiency and mechanical properties.This study primarily investigated the principal chemical groups and mechanism of action of TDCPS in promoting NRL vulcanization through a comparative analysis.The results indicated that the key functional groups(thioamide and pyridine)in TDCPS synergistically accelerated crosslinking,reducing the vulcanization time by 41.18%compared to the high-ammonia(HA)preservation system.At an optimal TDCPS dosage of 5 mmol·L^(−1),vulcanized films achieved a tensile strength of 34.18 MPa,with a sulfur content of 1.5 phr further improving the strength by 42.26%.TD outperformed the conventional accelerators 2-imidazolidinethione(ETU)and 3-hydroxypyridine(3-Hp)in promoting the crosslinking density and mechanical performance while eliminating ammonia-related environmental risks.This eco-friendly system demonstrates the industrial potential for sustainable rubber production.
