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
To explore the best preparation process for terminal blend(TB)composite-modified asphalt and to filter its formulation with excellent performance,this study evaluates the performance of TB composite modified asphalt b...To explore the best preparation process for terminal blend(TB)composite-modified asphalt and to filter its formulation with excellent performance,this study evaluates the performance of TB composite modified asphalt by physical property index,microscopic morphology,rheological testing,and infrared spectroscopy on multiple scales.The results show that the best preparation process for TB-modified asphalt is stirring at 260℃ for 4 h at 400 rpm,which significantly reduces the modification time of the asphalt.From a physical property viewpoint,the TB composite-modified asphalt sample with 5% styrene-butadiene-styrene(SBS)+1% aromatics+0.1% sulfur exhibits high-comprehensive,high-and low-temperature properties.More-over,its crosslinked mesh structure comprises black rubber particles uniformly interwoven in the middle,which further enhances the performance of the asphalt and results in an excellent performance formulation.In addition,the sample with 5%SBS content has a higher G*value and smaller δ value than that with 3%SBS content,indicating that its high-temperature resistance is improved.The effect of adding 3%SBS content on the viscoelastic ratio is,to some extent,less than that caused by 20% rubber powder.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 spe...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
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
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
Brominated butyl rubber(BIIR)is extensively utilized in products such as tyres and biomedical products owing to its excellent elasticity and gas barrier properties,while the recycling of the end-of-life BIIR products ...Brominated butyl rubber(BIIR)is extensively utilized in products such as tyres and biomedical products owing to its excellent elasticity and gas barrier properties,while the recycling of the end-of-life BIIR products remains a challenge because of the existence of a covalent cross-linked network.Herein,direct upcycling of unmodified waste BIIR is achieved through a nanoparticle-mediated interfacial crosslinking strategy,circumventing chemical modification or degradation of its polymer structure.Specifically,pyridyl-functionalized silica nanoparticles(SiO_(2)-Py)are synthesized and utilized to crosslink the bromine atoms in waste BIIR with those of fresh BIIR to reconstruct the crosslink network without altering the original sulfur-vulcanization network of waste BIIR.The resulting composites exhibit a dual interpenetrating network structure comprising the sulfur-vulcanized network and the bromine-pyridinium crosslinked silicarich network,which endows the composites with exceptional strength and toughness.As a result,the waste BIIR from the discarded bicycle inner tyres is successfully upcycled into highperformance BIIR composites,demonstrating superior tensile strength(~14 MPa),toughness(~60 MJ m^(-3)),and ultra-low air permeability(8.78×10^(-15)cm^(3)cm/(cm^(2)s Pa)),significantly outperforming the original material from bicycle inner tubes.This work presents a scalable and effective solution for BIIR waste recycling,offering great potential for advancing the sustainable development of the rubber industry.展开更多
Recycling of waste rubber(WR)is crucial for the sustainable development of the rubber industry.The enhancement of interfacial interactions is the main strategy for waste polymer recycling.However,there is a lack of me...Recycling of waste rubber(WR)is crucial for the sustainable development of the rubber industry.The enhancement of interfacial interactions is the main strategy for waste polymer recycling.However,there is a lack of methods for enhancing the interfacial interactions for WR recycling because WR contains abundant inert C―H bonds.Herein,we designed thioctic acid inverse vulcanization copolymers to endow recycled WR with dynamic disulfide interfacial interactions,significantly improving the mechanical properties of recycled WR.These disulfide interfacial interactions among the recycled WR tend to exchange,which dramatically increases the fractocohesive length and prevents stress concentration near the crack tips.When recycled WR is subjected to external stress,the loads are redistributed across a broad region of adjacent regions instead of being concentrated on a limited length scale,which resists crack propagation.This work effectively recycled WR,providing a strategy for solvent-free reaction-derived inverse vulcanization copolymers to improve the toughness of WR recycling.展开更多
This study investigates the potential of starch extracted from underutilized agro-industrial resources as non-food-competing raw materials for the development of flexible bioplastics for food packaging applications.St...This study investigates the potential of starch extracted from underutilized agro-industrial resources as non-food-competing raw materials for the development of flexible bioplastics for food packaging applications.Starch was extracted from three biomass sources:rubber cassava(Manihot glaziovii),banana stem,and banana peel from Ambonese banana(Musa acuminata L.).Rubber cassava starch(SRC)exhibited the highest starch yield(50.68±0.28%),significantly surpassing banana stem(SBS,14.20±0.25%)and banana peel(SBP,3.07±0.15%).The amylose contents of SRC,SBS,and SBP were 28.18%,52.80%,and 56.57%,respectively,while their amylopectin contents were 71.83%,47.20%,and 43.43%.FTIR spectra confirmed the absence of cyanogenic groups in SRC,indicating its safety for packaging applications.XRD analysis revealed that PSRC films were predominantly amorphous,while PSBS and PSBP showed higher crystallinity.The enhancement of mechanical properties,specifically PSBS,showed the highest tensile strength at 16.04±0.56 MPa,whereas PSRC demonstrated the highest elongation at break at 23.57±0.40%,which could be attributed to the inherent characteristics of the starch sources.Additionally,PSRC film exhibited the highest transparency at 60.2%,the greatest water solubility at 34.92%,and the lowest water contact angle at 41.58○,confirming its more hydrophilic nature compared to other films.This work highlights the potential of low-cost,sustainable,and non-food agro-industrial starch sources as promising candidates for the development of flexible,eco-friendly bioplastics.展开更多
The glass transition temperature(T_(g))of styrene-butadiene rubber(SBR)is a key parameter determining its low-temperature flexibility and processing performance.Accurate prediction of T_(g)is crucial formaterial desig...The glass transition temperature(T_(g))of styrene-butadiene rubber(SBR)is a key parameter determining its low-temperature flexibility and processing performance.Accurate prediction of T_(g)is crucial formaterial design and application optimisation.Addressing the limitations of traditional experimental measurements and theoretical models in terms of efficiency,cost,and accuracy,this study proposes a machine learning prediction framework that integrates multi-model ensemble and Bayesian optimization by constructing a multi-component feature dataset and algorithm optimization strategy.Based on the constructed high-quality dataset containing 96 SBR samples,ninemachine learning models were employed to predict the T_(g)of SBR and compare their prediction performance.Ultimately,aGPR-XGBoost mixed model was constructed through model ensemble,achieving high-precision prediction with R^(2)values greater than 0.9 on both the training and test sets.Further feature attribution and local effect analysis were conducted using feature analysis methods such as SHAP and ALE,revealing the nonlinear influence patterns of various components on T_(g),providing a theoretical basis for SBR formulation design and T_(g)regulation.The machine learning prediction framework established in this study combines high-precision prediction with interpretability,significantly enhancing the prediction performance of the T_(g)of SBR.It offers an efficient tool for SBR molecular design and holds great potential for promotion and application.展开更多
The disposal of discarded tires is a problem of significant proportion.In the present experimental study,rubber produced from the granulation of discarded tires was used as an additive to replace certain portions of m...The disposal of discarded tires is a problem of significant proportion.In the present experimental study,rubber produced from the granulation of discarded tires was used as an additive to replace certain portions of mineral aggregates in concrete.This rubberized concrete was used in making thin panels.A layer of polymer grid was used to reinforce the rubberized concrete panels.These panels were developed to study their performance in applications where the concrete could be subjected to flexure.Buildings constructed in areas with extreme wind pressures resulting from hurricanes or tornadoes are examples of structures that require concrete that can handle considerable deformation without failing catastrophically.Three different panel thicknesses,three different water-cement ratios,and three different rubber contents were the parameters evaluated in this study.All panels were loaded in bending with two equal loads applied at two equal distances from the supports.Test results showed that the flexural resistance of the panel increases with an increase in the thickness of the section,and with a reduction in the water-cement ratio of the concrete.The panels behaved in a ductile manner and there were no signs of brittle failure.Considerable deformation was measured during load application where loaded panels fractured but remained intact relying on the elongating polymer reinforcement.In addition to the lightweight properties,it was concluded that rubber concrete and polymer grid could be used as effective tools to impart ductility to the concrete and to control the mode and nature of the brittle failure of conventional concrete.展开更多
Herein,cure characteristics,morphology,and mechanical properties of natural rubber filled with activated carbon-based materials were investigated.Carbon-based materials were prepared from bagasse,coffee grounds and pi...Herein,cure characteristics,morphology,and mechanical properties of natural rubber filled with activated carbon-based materials were investigated.Carbon-based materials were prepared from bagasse,coffee grounds and pineapple crowns by the pyrolysis method at temperatures in the range of 300℃.As-synthesized carbon materials were characterized by optical microscopy(OM),scanning electron microscopy(SEM),and Fourier-transform infrared spectroscopy(FTIR)to analyze size distribution,morphology,and functional groups,respectively.OM and SEM analysis revealed that particles,flakes,and a small quantity of fiber-like carbon were obtained using bagasse and pineapple crown as raw materials,while honeycomb-like carbon materials can be derived from coffee grounds.To investigate the mechanical properties,natural rubber was filled with carbon black and as-synthesized carbon materials by the internal mixing and compression molding process.Transmission electron microscopy(TEM)was utilized to characterize the dispersion of carbon materials in the rubber matrix.The results of tensile testing showed that the natural rubber mixed with as-synthesized carbon materials from pineapple crowns exhibited 54%and 74%improvement in the ultimate tensile strength and Young’s modulus,respectively,compared with natural rubber without filled carbon materials.The enhancement in mechanical properties by activated carbon materials derived from pineapple crowns can be attributed to the flake-and fiber-like structures and good dispersion of carbon materials in the rubber matrix.In addition,it is higher than that of rubber mixed with carbon black.The results demonstrated that as-synthesized carbon materials from pineapple crowns have the potential materials to substitute carbon black in the rubber compound industry.展开更多
Purpose–The brake pipe system was an essential braking component of the railway freight trains,but the existing E-type sealing rings had problems such as insufficient low-temperature resistance,poor heat stability an...Purpose–The brake pipe system was an essential braking component of the railway freight trains,but the existing E-type sealing rings had problems such as insufficient low-temperature resistance,poor heat stability and short service life.To address these issues,low-phenyl silicone rubber was prepared and tested,and the finite element analysis and experimental studies on the sealing performance of its sealing rings were carried out.Design/methodology/approach–The low-temperature resistance and thermal stability of the prepared lowphenyl silicone rubber were studied using low-temperature tensile testing,differential scanning calorimetry,dynamic thermomechanical analysis and thermogravimetric analysis.The sealing performance of the lowphenyl silicone rubber sealing ring was studied by using finite element analysis software abaqus and experiments.Findings–The prepared low-phenyl silicone rubber sealing ring possessed excellent low-temperature resistance and thermal stability.According to the finite element analysis results,the finish of the flange sealing surface and groove outer edge should be ensured,and extrusion damage should be avoided.The sealing rings were more susceptible to damage in high compression ratio and/or low-temperature environments.When the sealing effect was ensured,a small compression ratio should be selected,and rubbers with hardness and elasticity less affected by temperature should be selected.The prepared low-phenyl silicone rubber sealing ring had zero leakage at both room temperature(RT)and�508C.Originality/value–The innovation of this study is that it provides valuable data and experience for the future development of the sealing rings used in the brake pipe flange joints of the railway freight cars in China.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Funded by the National Natural Science Foundation of China(No.52278446)。
文摘To explore the best preparation process for terminal blend(TB)composite-modified asphalt and to filter its formulation with excellent performance,this study evaluates the performance of TB composite modified asphalt by physical property index,microscopic morphology,rheological testing,and infrared spectroscopy on multiple scales.The results show that the best preparation process for TB-modified asphalt is stirring at 260℃ for 4 h at 400 rpm,which significantly reduces the modification time of the asphalt.From a physical property viewpoint,the TB composite-modified asphalt sample with 5% styrene-butadiene-styrene(SBS)+1% aromatics+0.1% sulfur exhibits high-comprehensive,high-and low-temperature properties.More-over,its crosslinked mesh structure comprises black rubber particles uniformly interwoven in the middle,which further enhances the performance of the asphalt and results in an excellent performance formulation.In addition,the sample with 5%SBS content has a higher G*value and smaller δ value than that with 3%SBS content,indicating that its high-temperature resistance is improved.The effect of adding 3%SBS content on the viscoelastic ratio is,to some extent,less than that caused by 20% rubber powder.
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 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 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 National Natural Science Foundation of China(52525301,52373061,and 52403072)the Sinopec Group Key R&D Project(223102)the State Key Laboratory of Advanced Polymer Materials(sklapm2025-2-14)。
文摘Brominated butyl rubber(BIIR)is extensively utilized in products such as tyres and biomedical products owing to its excellent elasticity and gas barrier properties,while the recycling of the end-of-life BIIR products remains a challenge because of the existence of a covalent cross-linked network.Herein,direct upcycling of unmodified waste BIIR is achieved through a nanoparticle-mediated interfacial crosslinking strategy,circumventing chemical modification or degradation of its polymer structure.Specifically,pyridyl-functionalized silica nanoparticles(SiO_(2)-Py)are synthesized and utilized to crosslink the bromine atoms in waste BIIR with those of fresh BIIR to reconstruct the crosslink network without altering the original sulfur-vulcanization network of waste BIIR.The resulting composites exhibit a dual interpenetrating network structure comprising the sulfur-vulcanized network and the bromine-pyridinium crosslinked silicarich network,which endows the composites with exceptional strength and toughness.As a result,the waste BIIR from the discarded bicycle inner tyres is successfully upcycled into highperformance BIIR composites,demonstrating superior tensile strength(~14 MPa),toughness(~60 MJ m^(-3)),and ultra-low air permeability(8.78×10^(-15)cm^(3)cm/(cm^(2)s Pa)),significantly outperforming the original material from bicycle inner tubes.This work presents a scalable and effective solution for BIIR waste recycling,offering great potential for advancing the sustainable development of the rubber industry.
基金financially supported by the National Natural Science Foundation of China(No.52363007)。
文摘Recycling of waste rubber(WR)is crucial for the sustainable development of the rubber industry.The enhancement of interfacial interactions is the main strategy for waste polymer recycling.However,there is a lack of methods for enhancing the interfacial interactions for WR recycling because WR contains abundant inert C―H bonds.Herein,we designed thioctic acid inverse vulcanization copolymers to endow recycled WR with dynamic disulfide interfacial interactions,significantly improving the mechanical properties of recycled WR.These disulfide interfacial interactions among the recycled WR tend to exchange,which dramatically increases the fractocohesive length and prevents stress concentration near the crack tips.When recycled WR is subjected to external stress,the loads are redistributed across a broad region of adjacent regions instead of being concentrated on a limited length scale,which resists crack propagation.This work effectively recycled WR,providing a strategy for solvent-free reaction-derived inverse vulcanization copolymers to improve the toughness of WR recycling.
基金supported by the RIIM BRIN and LPDP Grants,grant number B-2880/II.7.5/KS.00/4/2025 dan B-7930/III.6/TK.01.03/4/2025 under the scheme BRIN-KONEKSI Joint Call for Proposalsthe theme“Indonesia's Bioeconomy:Maximising Sustainable Marine Biodiversity Utilisation 2024”No 6/II.7/HK/2025.
文摘This study investigates the potential of starch extracted from underutilized agro-industrial resources as non-food-competing raw materials for the development of flexible bioplastics for food packaging applications.Starch was extracted from three biomass sources:rubber cassava(Manihot glaziovii),banana stem,and banana peel from Ambonese banana(Musa acuminata L.).Rubber cassava starch(SRC)exhibited the highest starch yield(50.68±0.28%),significantly surpassing banana stem(SBS,14.20±0.25%)and banana peel(SBP,3.07±0.15%).The amylose contents of SRC,SBS,and SBP were 28.18%,52.80%,and 56.57%,respectively,while their amylopectin contents were 71.83%,47.20%,and 43.43%.FTIR spectra confirmed the absence of cyanogenic groups in SRC,indicating its safety for packaging applications.XRD analysis revealed that PSRC films were predominantly amorphous,while PSBS and PSBP showed higher crystallinity.The enhancement of mechanical properties,specifically PSBS,showed the highest tensile strength at 16.04±0.56 MPa,whereas PSRC demonstrated the highest elongation at break at 23.57±0.40%,which could be attributed to the inherent characteristics of the starch sources.Additionally,PSRC film exhibited the highest transparency at 60.2%,the greatest water solubility at 34.92%,and the lowest water contact angle at 41.58○,confirming its more hydrophilic nature compared to other films.This work highlights the potential of low-cost,sustainable,and non-food agro-industrial starch sources as promising candidates for the development of flexible,eco-friendly bioplastics.
基金supported by the National Natural Science Foundation of China(grant numbers 52250357 and 52203003).
文摘The glass transition temperature(T_(g))of styrene-butadiene rubber(SBR)is a key parameter determining its low-temperature flexibility and processing performance.Accurate prediction of T_(g)is crucial formaterial design and application optimisation.Addressing the limitations of traditional experimental measurements and theoretical models in terms of efficiency,cost,and accuracy,this study proposes a machine learning prediction framework that integrates multi-model ensemble and Bayesian optimization by constructing a multi-component feature dataset and algorithm optimization strategy.Based on the constructed high-quality dataset containing 96 SBR samples,ninemachine learning models were employed to predict the T_(g)of SBR and compare their prediction performance.Ultimately,aGPR-XGBoost mixed model was constructed through model ensemble,achieving high-precision prediction with R^(2)values greater than 0.9 on both the training and test sets.Further feature attribution and local effect analysis were conducted using feature analysis methods such as SHAP and ALE,revealing the nonlinear influence patterns of various components on T_(g),providing a theoretical basis for SBR formulation design and T_(g)regulation.The machine learning prediction framework established in this study combines high-precision prediction with interpretability,significantly enhancing the prediction performance of the T_(g)of SBR.It offers an efficient tool for SBR molecular design and holds great potential for promotion and application.
文摘The disposal of discarded tires is a problem of significant proportion.In the present experimental study,rubber produced from the granulation of discarded tires was used as an additive to replace certain portions of mineral aggregates in concrete.This rubberized concrete was used in making thin panels.A layer of polymer grid was used to reinforce the rubberized concrete panels.These panels were developed to study their performance in applications where the concrete could be subjected to flexure.Buildings constructed in areas with extreme wind pressures resulting from hurricanes or tornadoes are examples of structures that require concrete that can handle considerable deformation without failing catastrophically.Three different panel thicknesses,three different water-cement ratios,and three different rubber contents were the parameters evaluated in this study.All panels were loaded in bending with two equal loads applied at two equal distances from the supports.Test results showed that the flexural resistance of the panel increases with an increase in the thickness of the section,and with a reduction in the water-cement ratio of the concrete.The panels behaved in a ductile manner and there were no signs of brittle failure.Considerable deformation was measured during load application where loaded panels fractured but remained intact relying on the elongating polymer reinforcement.In addition to the lightweight properties,it was concluded that rubber concrete and polymer grid could be used as effective tools to impart ductility to the concrete and to control the mode and nature of the brittle failure of conventional concrete.
基金funded by Faculty of Engineering,Burapha University,grant number 003/2567.
文摘Herein,cure characteristics,morphology,and mechanical properties of natural rubber filled with activated carbon-based materials were investigated.Carbon-based materials were prepared from bagasse,coffee grounds and pineapple crowns by the pyrolysis method at temperatures in the range of 300℃.As-synthesized carbon materials were characterized by optical microscopy(OM),scanning electron microscopy(SEM),and Fourier-transform infrared spectroscopy(FTIR)to analyze size distribution,morphology,and functional groups,respectively.OM and SEM analysis revealed that particles,flakes,and a small quantity of fiber-like carbon were obtained using bagasse and pineapple crown as raw materials,while honeycomb-like carbon materials can be derived from coffee grounds.To investigate the mechanical properties,natural rubber was filled with carbon black and as-synthesized carbon materials by the internal mixing and compression molding process.Transmission electron microscopy(TEM)was utilized to characterize the dispersion of carbon materials in the rubber matrix.The results of tensile testing showed that the natural rubber mixed with as-synthesized carbon materials from pineapple crowns exhibited 54%and 74%improvement in the ultimate tensile strength and Young’s modulus,respectively,compared with natural rubber without filled carbon materials.The enhancement in mechanical properties by activated carbon materials derived from pineapple crowns can be attributed to the flake-and fiber-like structures and good dispersion of carbon materials in the rubber matrix.In addition,it is higher than that of rubber mixed with carbon black.The results demonstrated that as-synthesized carbon materials from pineapple crowns have the potential materials to substitute carbon black in the rubber compound industry.
基金supported by the Science and Technology Research and Development Plan of the China State Railway Group Company Limited(No.Q2023J012).
文摘Purpose–The brake pipe system was an essential braking component of the railway freight trains,but the existing E-type sealing rings had problems such as insufficient low-temperature resistance,poor heat stability and short service life.To address these issues,low-phenyl silicone rubber was prepared and tested,and the finite element analysis and experimental studies on the sealing performance of its sealing rings were carried out.Design/methodology/approach–The low-temperature resistance and thermal stability of the prepared lowphenyl silicone rubber were studied using low-temperature tensile testing,differential scanning calorimetry,dynamic thermomechanical analysis and thermogravimetric analysis.The sealing performance of the lowphenyl silicone rubber sealing ring was studied by using finite element analysis software abaqus and experiments.Findings–The prepared low-phenyl silicone rubber sealing ring possessed excellent low-temperature resistance and thermal stability.According to the finite element analysis results,the finish of the flange sealing surface and groove outer edge should be ensured,and extrusion damage should be avoided.The sealing rings were more susceptible to damage in high compression ratio and/or low-temperature environments.When the sealing effect was ensured,a small compression ratio should be selected,and rubbers with hardness and elasticity less affected by temperature should be selected.The prepared low-phenyl silicone rubber sealing ring had zero leakage at both room temperature(RT)and�508C.Originality/value–The innovation of this study is that it provides valuable data and experience for the future development of the sealing rings used in the brake pipe flange joints of the railway freight cars in China.
