In order to evaluate the feasibility of steel slag powder as filler,the coating properties of steel slag and limestone aggregate were compared by water boiling test,the micro morphology difierences between steel slag ...In order to evaluate the feasibility of steel slag powder as filler,the coating properties of steel slag and limestone aggregate were compared by water boiling test,the micro morphology difierences between steel slag powder and mineral powder(limestone powder)were compared by scanning electron microscope(SEM),and the high-temperature rheological properties of asphalt mortar with difierent ratio of filler quality to asphalt quality(F/A)and difierent substitution rates of mineral powder(S/F)were studied by dynamic shear rheological test.The results show that the surface microstructure of steel slag powder is more abundant than that of mineral powder,and the adhesion of steel slag to asphalt is better than that of limestone.At the same temperature,the lower the ratio of S/F is,the greater the rutting factor and complex modulus will be.In addition,the complex modulus and rutting factor of the asphalt mortar increase with the increase of F/A,and the filler type and F/A have a negligible efiect on the phase angle.展开更多
The theological behavior of poly(vinylidene fluoride)(PVDF)samples of different molecular weights was investigated by means of high pressure capillary rheometer and rotational rheometer.Information on the rheological ...The theological behavior of poly(vinylidene fluoride)(PVDF)samples of different molecular weights was investigated by means of high pressure capillary rheometer and rotational rheometer.Information on the rheological properties of such materials above melt temperatures is of interest as this can lead to an improved understanding of polymer behavior in processing and fabrication technologies.Shift factors derived from time-temperature superposition showed good fit to the Arrhenius equation with a flow act...展开更多
This paper presents an investigation into modelling the rheological properties of epoxy asphalt concrete( EAC) by using the Huet-Sayegh model. Complex modulus tests were conducted on EAC specimens at various temperatu...This paper presents an investigation into modelling the rheological properties of epoxy asphalt concrete( EAC) by using the Huet-Sayegh model. Complex modulus tests were conducted on EAC specimens at various temperature and loading frequency conditions. Dynamic modulus and phase angles obtained from the complex modulus tests were used in the construction of the Huet-Sayegh model. The dynamic modulus master curve was developed by the Huet-Sayegh model as well as the Burgers model for comparison purpose. The results showed that EAC exhibits typical rheological behavior whose dynamic modulus decreases with the increase of temperature while increases with the increase of frequency,and phase angles increase with the decrease of frequencies and the increase of temperatures. The Huet-Sayegh model predicts the dynamic modulus master curve of EAC very well and much better than the Burgers model over a wide range of frequencies.展开更多
The rheological properties of cement-based grouts containing talc or palygorskite were investigated for optimizing fluidity and quick strengthening at injection. The fluidity controls the ability of grout to penetrate...The rheological properties of cement-based grouts containing talc or palygorskite were investigated for optimizing fluidity and quick strengthening at injection. The fluidity controls the ability of grout to penetrate fractures and can be determined by pipe flow tests, Marsh funnel tests, mini-slump cone tests and rheometer tests. The grouts were 1) Talc for fluidity and strength by reacting with cement, 2) Palygorskite (attapulgite) for early gelation by being thixotropic, and 3) Powdered quartz for chemical integrity. The freshly prepared grouts behaved as Bingham fluids with viscosities from 0.151 to 0.464 Pas and yield stresses 5.2 Pa to 36.7 Pa. Statistical analysis of the flow test data converted Marsh flow time into viscosity. The pipe flow tests gave 26.5% higher values than the viscometer for grout with Portland cement and talc, and about 13.7% lower than the viscometer data for the grout with low-pH cement and talc. The big Marsh funnel gave values differing by 5.2% - 5.3% from those of the viscometer for grout with talc and Portland, and Merit 5000 cements. For grout with palygorskite the viscosity was at least twice that of the other grouts. Grout fluidity was positively affected by talc and negatively by palygorskite and early cement hydration.展开更多
In this paper,the surface activated crumb rubber with waste cooking oil(WCO)was studied to improve the performance of crumb rubber modified asphalt.The activated waste crumb rubber modified asphalt(OCRMA)with differen...In this paper,the surface activated crumb rubber with waste cooking oil(WCO)was studied to improve the performance of crumb rubber modified asphalt.The activated waste crumb rubber modified asphalt(OCRMA)with different amount of crumb rubber was prepared to study the microscopic appearance of OCRMA by scanning electron microscope and fluorescence microscope and analyze the surface performance.The rheological properties and microscopic mechanism of OCRMA were characterized by dynamic shear rheological test,multiple stress creep recovery(MSCR)test,BBR test and infrared spectroscopy.The results show that the dissolution degree of waste crumb rubber is improved after WCO activation,and the compatibility with asphalt components is enhanced,and the stable cross-linking structure is formed,which improves the asphalt performance.The several new absorption peaks,which were obvious,were all caused by the composition of WCO,that is,there was no significant chemical change during the interaction between the activated crumb rubber and base asphalt.Compared with the common waste crumb rubber modified asphalt(CRMA),activation with WCO can significantly reduce the viscosity of CRMA,decrease the difference of segregation softening point by 27%,and enhance the low temperature performance by 30%.The aging degree is greatly reduced,and the anti-aging performance of OCRMA is increased by about 20%with the same dosage.The high temperature performance,though higher than that of base asphalt,decreases to some extent.After comprehensive analysis,the optimal dosage of crumb rubber for OCRMA is 30%.展开更多
SBS(styrene-butadiene-styrene block copolymer)has been widely used in pavement industry as an asphalt modifier.Nanomaterials can further enhance the performance of SBS modified asphalt.However,rare studies investigate...SBS(styrene-butadiene-styrene block copolymer)has been widely used in pavement industry as an asphalt modifier.Nanomaterials can further enhance the performance of SBS modified asphalt.However,rare studies investigate the feasibility of using graphene as a performance enhancer of SBS modified asphalt.To fill this gap,comprehensive experimental tests including chemical and mechanical test were carried out on SBS-graphene modified asphalt and SEBS(styrene-ethylene-butylene-styrene block copolymer,which is a hydrogenated polymer of SBS)modified asphalt.Graphene with different dimensions and contents was taken into consideration in this study.Based on the experimental work,it can be concluded that graphene improves the mid-temperature performance of SBS modified asphalt.Compared with two-dimensional graphene,three-dimensional graphene has a greater advantage and the enhancement effect increases with the increase of its dosage.In addition,the cross-linked structure of SBS-graphene composite improves the distribution of SBS in asphalt,which improves the overall performance of SBS modified asphalt.展开更多
The effects of thermal history on the rheological properties of partially hydrolyzed polyacrylamide/ sodium dodecyl sulfate complex aqueous solutions have been studied using both steady shear and dynamic temperature s...The effects of thermal history on the rheological properties of partially hydrolyzed polyacrylamide/ sodium dodecyl sulfate complex aqueous solutions have been studied using both steady shear and dynamic temperature sweep characterizations. An abnormal rheological behavior was found that dynamic moduli of the aqueous solutions increased, while the viscosity decreased after thermal treatment, which could help to gain insight into the micro-phase evolution of the polymer/surfactant complex aqueous solutions and its dependence on temperature.展开更多
In order to investigate the effect of the relative motion of nano CaCO_(3)reinforced bamboo pulp fiber(BPF)/HDPE composite components on the mechanical performance,a comparative study was performed.BPF was treated by ...In order to investigate the effect of the relative motion of nano CaCO_(3)reinforced bamboo pulp fiber(BPF)/HDPE composite components on the mechanical performance,a comparative study was performed.BPF was treated by nano CaCO_(3)blending(BM)and impregnation modification(IM)technology.The composites were produced using hot press(HPMP),extrusion(EMP)and injection molding process(IMP).The physical morphology of BPF was similar at different manufacturing processes.Compared to the samples manufactured by HPMP,a decrease in the(specific)flexural strength of BPF/HDPE composites and an increase in those of composites treated by nano CaCO_(3)manufactured by EMP and IMP were observed.The injection molded composites exhibited the best values in the(specific)impact strength,(specific)tensile properties.IM had a greater effect on the rheological behavior of the composites than BM,and nano CaCO_(3)treatment most effectively affected the performance of the extrusion molded composites.展开更多
The effect of reduced glutathione (GSH) on fresh and pre-proofed frozen dough rheological properties were investigated using dynamic stress rheometry and small scale extensibility with the addition of three levels (80...The effect of reduced glutathione (GSH) on fresh and pre-proofed frozen dough rheological properties were investigated using dynamic stress rheometry and small scale extensibility with the addition of three levels (80×10-6, 160× 10-6 and 240×10-6 GSH) and six storage times (0 and 1 day, 2, 4, 6 and 8 weeks). Three relaxation times (1, 13 and 26min) after loading the dough in the rheometer were used to determine storage (G’) and loss (G”) moduli. Correlations for G’ (r=0.678 and 0.622 at 0.05, and 10Hz, respectively) and G” (r=0.699, and 0.690 at 0.05, and 10Hz, respectively) were observed with the area under the extension curve at 26 min relaxation time. The addition of GSH to fresh dough reduced G’ (16.4% to 55.9%) and G” (13.7% to 52.2%). Freezing and frozen storage caused increase in G’ and G”. The addition of GSH reduced dough strength indicated by the reduction in maximum resistance to extension (Rmax) and the ratio of maximum resistance to extensibility (Rmax/E). The reduction in Rmax across all relaxation times ranged from 16.2% to 59.4%. An increase in dough extension (E) was observed with 240×10-6 GSH at all frozen storage and rest period times. Addition of GSH caused an increase of liquid phase (30.6% to 35.3%) in fresh dough and frozen dough (10.3% to 20.7%) after one day frozen storage. Negative correlations of water content in the solid phase with dough extensibility and area under the extensibility curve were found (r=-0.594 and-0.563, respectively, p<0.001). This suggests a loss of dough extensibility and strength as the water holding capacity of the dough components changes during frozen storage.展开更多
The rheological properties of wheat flour are very important for the production of bakery products,and the milling methods greatly influence the rheological properties.In this paper,we measured the particle size distr...The rheological properties of wheat flour are very important for the production of bakery products,and the milling methods greatly influence the rheological properties.In this paper,we measured the particle size distributions,damaged starch contents,granular morphology,and pasting properties of the wheat flour,also carried out the uniaxial elongation test,the texture profile analysis,and rheological properties of the dough to evaluate effects of two milling methods,i.e.impact mill(IM)and hammer mill(HM),on the rheological properties of wheat flour and dough.The results showed that milling methods had no significant effects on flour pasting temperature(except the flour H3 obtained by HM grinding three times)and springiness of dough.Flour samples milled by IM had a lower damaged starch content,higher trough viscosity,higher final viscosity and higher values of setback compared to samples processed by HM.After repeated milling of IM,the damaged starch content of the endosperm granules could be controlled below 1%(P<0.05).There was a gap between H1 and H2 in the elastic modulus value of the non-fermented dough group,and the difference increased after fermentation,which was more obvious in the values of viscosity modulus.The more the milling times,the greater the elastic and viscosity modulus of dough of flour processed by both IM and HM.展开更多
The baking quality of sorghum-wheat bread is equally reliant on the quantity and the quality of protein existent in the composite flours. A lot of procedures have been proposed for expanding the use of sorghum either ...The baking quality of sorghum-wheat bread is equally reliant on the quantity and the quality of protein existent in the composite flours. A lot of procedures have been proposed for expanding the use of sorghum either as a composite flour blended with wheat or potentially as a straight flour. In any case,the amount of flour that can be subbed is up to a specific degree of sorghum flour to deliver sensory attractive products. The manipulation of the chemical composition, textural properties of the sorghum kernel, and selection of a proper hybrid could proffer desirable value addition results in bread making.The quality of the flour and the adherence to acceptable flour size standards is the key to producing good quality bread. In this paper, the effects of adding sorghum flour on dough rheological properties and the quality of bread were discussed in detail.展开更多
Regulating rheological properties of water-based drilling fluids has always been a hot topic.This paper proposed a new method for regulating rheological properties of water-based drilling fluids by ultrasonic field.Th...Regulating rheological properties of water-based drilling fluids has always been a hot topic.This paper proposed a new method for regulating rheological properties of water-based drilling fluids by ultrasonic field.The experimental results showed that the ultrasound increased the viscosity and yield point of bentonite suspension by reducing the particle size of clay,destroying the network structure between clay particles,increasing the mud yield and the cation exchange capacity of bentonite,and promoting the hydration dispersion of bentonite.The change of rheological property showed a memory effect at room temperature and high temperature.Besides,the ultrasonic energy affected the network structure between clays and polymer chains,thus regulating the rheological properties of the bentonite-polymer system.For two types of drilling fluids investigated,the rheology of the poly-sulfonate drilling fluid was regulated by damaging the grid structure between additives and clays by low-power ultrasound and reducing the clay particle size by high-power ultrasound,while the rheology of the deep-water drilling fluid was mainly regulated by disentangling the spatial grid structure between additives.Additionally,ultrasound showed no effect on the lubricity,inhibition and stability of drilling fluids,which proved the feasibility of ultrasound to regulate rheological properties of water-based drilling fluids.展开更多
Global ecological concerns have resulted in an interest in renewable natural materials. Composites based on high density polyethylene (HDPE), wood fiber (Veneer) and containing coupling agents like nanoclay (NC) and p...Global ecological concerns have resulted in an interest in renewable natural materials. Composites based on high density polyethylene (HDPE), wood fiber (Veneer) and containing coupling agents like nanoclay (NC) and poly-ethylene-co-glycidyl methacrylate (PEGMA) were made by melt compounding and then injection molding. In this study, the effects of two variable parameters namely nanoclay and coupling agent on the rheological and thermal properties of wood polyethylene composites (WPECs) were investigated. The study investigates the morphology phase, rheology behaviors and thermal properties by scanning electron microscope, capillary rheometer and thermal gravimetric analyzer. The SEM micrographs of the composites showed that the outer surfaces of the wood were coated by a section of amorphous lignin. The state of dispersion in HDPE/pine/clay composites was improved by EGMA because it could interact with pine flour in addition to clay. The interaction of reinforcement with coupling agent and HDPE matrix is strong based on the observation of the fracture surface of composites when EGMA is present. However the addition of 2.5% clay slightly lowered the initial degradation temperature (Td) but did not improve the thermal stability. Obviously, all the composites materials exhibit viscoelastic values greater than those of neat HDPE.展开更多
This work investigated the aging effects on the rheological properties of high viscosity modified asphalt(HVMA).First,the high-and low-temperature rheological properties were measured by a dynamic shear rheometer and ...This work investigated the aging effects on the rheological properties of high viscosity modified asphalt(HVMA).First,the high-and low-temperature rheological properties were measured by a dynamic shear rheometer and a bending beam rheometer,respectively.The aging mechanism was then tested using an Fourier transform infrared spectroscopy and a scanning electron microscope.Besides,a study was performed to compare the aging effects on the rheological properties of HVMA,crumb rubber modified asphalt(CRMA),and neat asphalt(SK-90).The experimental results showed that the effects of the long-term aging on HVMA exceeded those of short-term aging.The complex shear modulus of the HVMA was improved by the aging in the whole frequency range.The complex shear modulus of the HVMA after the long-term aging was larger than after the short-term aging.Thus,the aging improved the high-temperature viscoelastic performance of HVMA.With a decrease in temperature from-12℃to-24℃,the low-temperature viscoelastic performance of HVMA decreased since its stiffness modulus and low continuous grading temperature increase.Both of the short-and long-term aging of HVMA were caused by an oxidation reaction,while modifier swelling also happened after long-term aging.Compared to CRMA and SK-90,aging had a limited influence on the high-and low-temperature rheological properties of HVMA.展开更多
Rod milling sand(RMS)—a coarse sand aggregate—was recycled for cemented paste backfill(CPB)for the underground mined area at the Jinchuan nickel deposit,named rod milling sand-based cemented paste backfill(RCPB).The...Rod milling sand(RMS)—a coarse sand aggregate—was recycled for cemented paste backfill(CPB)for the underground mined area at the Jinchuan nickel deposit,named rod milling sand-based cemented paste backfill(RCPB).The adverse effects of coarse particles on the transportation of CPB slurry through pipelines to underground stopes resulting in weakening of the stability of the backfill system are well known.Therefore,sulfonated naphthalene formaldehyde(SNF)condensate was used for the performance improvement of RCPB.The synergistic effect of solid content(SC),lime-to-sand ratio,and SNF dosage on the rheological and physicomechanical properties,including slump,yield stress,bleeding rate,uniaxial compressive strength(UCS),as well as mechanism analysis of RCPB,have been explored.The results indicate that the effect of SNF on RCPB performance is related to the SNF dosage,lime-to-sand ratio,and SC.The slump of fresh RCPB with 0.1wt%-0.5wt%SNF increased by 2.6%-26.2%,whereas the yield stress reduced by 4.1%-50.3%,indicating better workability and improved cohesiveness of the mix.The bleeding rate of fresh RCPB decreased first and then rose with the increase of SNF dosage,and the peak decrease was 67.67%.UCS of RCPB first increased and then decreased with the increase of SNF dosage.At the optimal SNF addition ratio of 0.3wt%,the UCS of RCPB curing for 7,14 and,28 d ages increased by 31.5%,28.4%,and 29.5%,respectively.The beneficial effects of SNF in enhancing the early UCS of RCPB have been corroborated.However,the later UCS increases at a slower rate.The research findings may guide the design and preparation of RCPB with adequate performance for practical applications.展开更多
Polypropylene(PP)grease holds great potential for special industrial applications.In this study,synthetic conditions,thickener content,and the ratio of two different molecular weight PPs were investigated systematical...Polypropylene(PP)grease holds great potential for special industrial applications.In this study,synthetic conditions,thickener content,and the ratio of two different molecular weight PPs were investigated systematically using a rheometer,scanning electron microscope,X-ray diffraction,Fourier transform infrared spectrometer,oscillating tribometer,and 3D surface profiler measurements.The results showed that suitable synthetic conditions are two quenching cycles,and the synthetic temperature and time is 240℃for 12 h.The rheological analysis showed that thickener content and different proportions of the two PP molecular weights have a significant influence on the rheological properties of PP grease.High molecular weight PP(H-PP)has a stronger thickening ability than low molecular weight PP(L-PP).The higher the amount of H-PP in the fixed thickener content or the higher the thickener content with a specific proportion,the higher the viscoelasticity of PP grease.The tribological performance is related to the rheological properties.The proportion of two different molecular weight PPs in the thickener content should be appropriate;excessive H-PP content leads to lubrication failure.展开更多
Extrudability and constructability are two important,yet contradictory issues pertaining to the construction of three-dimensional(3D)printing concrete.Extrudability is easily achieved when 3D printing cement mortar ha...Extrudability and constructability are two important,yet contradictory issues pertaining to the construction of three-dimensional(3D)printing concrete.Extrudability is easily achieved when 3D printing cement mortar has a high water content and low cohesion,but the printed structure is easily collapsible.However,a 3D printing cement mortar with a low water content and high cohesion has a relatively stable printed structure although the cement mortar might not be extrudable.This study proposes a particle-based method to simulate 3D printing mortar extrusion and construction as an overall planning tool for building design.First,a discrete element model with time-varying liquid bridge forces is developed to investigate the microscopic effects of these forces on global rheological properties.Next,a series of numerical simulations relevant to 3D printable mortar extrudability and constructability are carried out.The study demonstrates that the effects of time-varying liquid bridge forces on rheological properties and the resulting extrudability and constructability of 3D printing mortar are considerable.Furthermore,an optimized region that satisfies both the extrusion and construction requirements is provided for 3D printing industry as a reference.展开更多
High viscosity asphalt(HVA)has been a great success as a drainage pavement material.However,the larger porosity of drainage asphalt mixtures weakens the cohesion and adhesion and leads to premature rutting,water damag...High viscosity asphalt(HVA)has been a great success as a drainage pavement material.However,the larger porosity of drainage asphalt mixtures weakens the cohesion and adhesion and leads to premature rutting,water damage,spalling and cracking.The purpose of this study was to investigate the rheological properties of HVA prepared using different high viscosity modifiers through conventional tests,Brookfield viscosity tests,dynamic shear rheometer tests and bending beam rheometer tests.The conventional performance results demonstrated SBS+rubber asphalt(SRA1/2)exhibited excellent elastic recovery and low-temperature flexibility.The 60℃ dynamic viscosity results indicated TPS+rubber asphalt(TRA)had the excellent adhesion.The rotational viscosity results and rheological results indicated that SRA-2 not only exhibited excellent temperature stability and workability,as well as excellent resistance to deformation and rutting resistance,but also exhibited excellent low-temperature cracking resistance and relaxation performance.Based on rheological results,the PG classification of HVA was 16%rubber+asphalt for PG76-22,20%rubber+asphalt for PG88-22,TRA and SRA-1/2 for PG88-28.From comprehensive evaluation of the viscosity,temperature stability and sensitivity,as well as high/low temperature performance of HVA,SRA-2 was found to be more suited to the requirements of drainage asphalt pavement materials.展开更多
This study investigated the effects of natural rubber(NR)and an organic peroxide on the rheological properties,mechanical properties,morphology,and bubble stability during film blowing of poly(lactic acid)(PLA).The NR...This study investigated the effects of natural rubber(NR)and an organic peroxide on the rheological properties,mechanical properties,morphology,and bubble stability during film blowing of poly(lactic acid)(PLA).The NR and peroxide contents were varied from 0 wt%to 25 wt%and 0 wt%to 0.5 wt%,respectively.The results confirmed that the presence of well-dispersed NR could significantly improve the toughness,elongation at break,and processability of PLA films,where the optimal amount of NR was 15 wt%.For the reactive blending with peroxide,a suitable peroxide content for good film toughness and clarity was 0.03 wt%,while the higher content of 0.1 wt%could provide slightly higher processability.These contents are considered much lower than that in the PLA system(without NR),which required up to 0.5 wt%peroxide.The rheological studies indicated that the melt strength,the storage modulus(G’)and complex viscosity(η*)at low frequency could be correlated with good film blowing processability of the PLA/NR films at low gel contents.These parameters failed to correlate in the films having high gel contents as the deformation rate experienced by each test was different leading to the different levels of response to the type and amount of gels.展开更多
The rheological properties of flaxseed meal(FM)and Soybean Protein Isolate(SPI)extruded by the two-screw extruder under different processing conditions were investigated.Moisture,temperature,screw speed and SPI concen...The rheological properties of flaxseed meal(FM)and Soybean Protein Isolate(SPI)extruded by the two-screw extruder under different processing conditions were investigated.Moisture,temperature,screw speed and SPI concentration were the four major factors for the extrusion process.The rheological properties of extruded products were calculated by steady state flow test,frequency sweep test and creep test.All the samples showed shear-thinning effect that is to say their apparent viscosities decreased with the increases of shear rate.The data fitted well to Power Law model.It was found that both the storage(G′)and loss modulus increased as the rise in the angular frequency(w),which also fitted well to Power Law model.The creep-recovery behavior of the samples fitted well to Burger’s model.In addition,the temperature had no significant effect on the creep recovery rate of the samples.展开更多
基金Funded by National Natural Science Foundation of China(No.52278446)。
文摘In order to evaluate the feasibility of steel slag powder as filler,the coating properties of steel slag and limestone aggregate were compared by water boiling test,the micro morphology difierences between steel slag powder and mineral powder(limestone powder)were compared by scanning electron microscope(SEM),and the high-temperature rheological properties of asphalt mortar with difierent ratio of filler quality to asphalt quality(F/A)and difierent substitution rates of mineral powder(S/F)were studied by dynamic shear rheological test.The results show that the surface microstructure of steel slag powder is more abundant than that of mineral powder,and the adhesion of steel slag to asphalt is better than that of limestone.At the same temperature,the lower the ratio of S/F is,the greater the rutting factor and complex modulus will be.In addition,the complex modulus and rutting factor of the asphalt mortar increase with the increase of F/A,and the filler type and F/A have a negligible efiect on the phase angle.
基金the Special Funds for Major State Basic Research Projects,China(No.2003CB615705).
文摘The theological behavior of poly(vinylidene fluoride)(PVDF)samples of different molecular weights was investigated by means of high pressure capillary rheometer and rotational rheometer.Information on the rheological properties of such materials above melt temperatures is of interest as this can lead to an improved understanding of polymer behavior in processing and fabrication technologies.Shift factors derived from time-temperature superposition showed good fit to the Arrhenius equation with a flow act...
基金Sponsored by the Natgional Natural Science Foundation of China(Grant No.51208103)the China Postdoctoral Science Foundation(Grant No.2012M520976)the Basic Research Foundation of Southeast University
文摘This paper presents an investigation into modelling the rheological properties of epoxy asphalt concrete( EAC) by using the Huet-Sayegh model. Complex modulus tests were conducted on EAC specimens at various temperature and loading frequency conditions. Dynamic modulus and phase angles obtained from the complex modulus tests were used in the construction of the Huet-Sayegh model. The dynamic modulus master curve was developed by the Huet-Sayegh model as well as the Burgers model for comparison purpose. The results showed that EAC exhibits typical rheological behavior whose dynamic modulus decreases with the increase of temperature while increases with the increase of frequency,and phase angles increase with the decrease of frequencies and the increase of temperatures. The Huet-Sayegh model predicts the dynamic modulus master curve of EAC very well and much better than the Burgers model over a wide range of frequencies.
文摘The rheological properties of cement-based grouts containing talc or palygorskite were investigated for optimizing fluidity and quick strengthening at injection. The fluidity controls the ability of grout to penetrate fractures and can be determined by pipe flow tests, Marsh funnel tests, mini-slump cone tests and rheometer tests. The grouts were 1) Talc for fluidity and strength by reacting with cement, 2) Palygorskite (attapulgite) for early gelation by being thixotropic, and 3) Powdered quartz for chemical integrity. The freshly prepared grouts behaved as Bingham fluids with viscosities from 0.151 to 0.464 Pas and yield stresses 5.2 Pa to 36.7 Pa. Statistical analysis of the flow test data converted Marsh flow time into viscosity. The pipe flow tests gave 26.5% higher values than the viscometer for grout with Portland cement and talc, and about 13.7% lower than the viscometer data for the grout with low-pH cement and talc. The big Marsh funnel gave values differing by 5.2% - 5.3% from those of the viscometer for grout with talc and Portland, and Merit 5000 cements. For grout with palygorskite the viscosity was at least twice that of the other grouts. Grout fluidity was positively affected by talc and negatively by palygorskite and early cement hydration.
基金This study was supported by Hunan Provincial Natural Science Foundation(Project No.2021JJ30709)Changsha Municipal Natural Science Foundation(Project No.kq2007029)Practice Innovation and Entrepreneurship Enhancement Program for Postgraduate of Changsha University of Science&Technology(Project No.SJCX202112).
文摘In this paper,the surface activated crumb rubber with waste cooking oil(WCO)was studied to improve the performance of crumb rubber modified asphalt.The activated waste crumb rubber modified asphalt(OCRMA)with different amount of crumb rubber was prepared to study the microscopic appearance of OCRMA by scanning electron microscope and fluorescence microscope and analyze the surface performance.The rheological properties and microscopic mechanism of OCRMA were characterized by dynamic shear rheological test,multiple stress creep recovery(MSCR)test,BBR test and infrared spectroscopy.The results show that the dissolution degree of waste crumb rubber is improved after WCO activation,and the compatibility with asphalt components is enhanced,and the stable cross-linking structure is formed,which improves the asphalt performance.The several new absorption peaks,which were obvious,were all caused by the composition of WCO,that is,there was no significant chemical change during the interaction between the activated crumb rubber and base asphalt.Compared with the common waste crumb rubber modified asphalt(CRMA),activation with WCO can significantly reduce the viscosity of CRMA,decrease the difference of segregation softening point by 27%,and enhance the low temperature performance by 30%.The aging degree is greatly reduced,and the anti-aging performance of OCRMA is increased by about 20%with the same dosage.The high temperature performance,though higher than that of base asphalt,decreases to some extent.After comprehensive analysis,the optimal dosage of crumb rubber for OCRMA is 30%.
基金The authors sincerely acknowledge the funding support from National Natural Science Foundation of China(51678251)Central University's Basic Research Business Fees Transformation and Cultivation Project(2018KZ001)Trademark or manufacturers'names appear in this paper only because they are considered essential to the object of this paper.
文摘SBS(styrene-butadiene-styrene block copolymer)has been widely used in pavement industry as an asphalt modifier.Nanomaterials can further enhance the performance of SBS modified asphalt.However,rare studies investigate the feasibility of using graphene as a performance enhancer of SBS modified asphalt.To fill this gap,comprehensive experimental tests including chemical and mechanical test were carried out on SBS-graphene modified asphalt and SEBS(styrene-ethylene-butylene-styrene block copolymer,which is a hydrogenated polymer of SBS)modified asphalt.Graphene with different dimensions and contents was taken into consideration in this study.Based on the experimental work,it can be concluded that graphene improves the mid-temperature performance of SBS modified asphalt.Compared with two-dimensional graphene,three-dimensional graphene has a greater advantage and the enhancement effect increases with the increase of its dosage.In addition,the cross-linked structure of SBS-graphene composite improves the distribution of SBS in asphalt,which improves the overall performance of SBS modified asphalt.
基金This work was supported by 973 Project "Fundamental Study on Enhanced Oil Recovery"(G1999022500).
文摘The effects of thermal history on the rheological properties of partially hydrolyzed polyacrylamide/ sodium dodecyl sulfate complex aqueous solutions have been studied using both steady shear and dynamic temperature sweep characterizations. An abnormal rheological behavior was found that dynamic moduli of the aqueous solutions increased, while the viscosity decreased after thermal treatment, which could help to gain insight into the micro-phase evolution of the polymer/surfactant complex aqueous solutions and its dependence on temperature.
基金This study is financially supported by the Basic Research Operating Expenses Program of International Centre for Bamboo and Rattan(1632021002).
文摘In order to investigate the effect of the relative motion of nano CaCO_(3)reinforced bamboo pulp fiber(BPF)/HDPE composite components on the mechanical performance,a comparative study was performed.BPF was treated by nano CaCO_(3)blending(BM)and impregnation modification(IM)technology.The composites were produced using hot press(HPMP),extrusion(EMP)and injection molding process(IMP).The physical morphology of BPF was similar at different manufacturing processes.Compared to the samples manufactured by HPMP,a decrease in the(specific)flexural strength of BPF/HDPE composites and an increase in those of composites treated by nano CaCO_(3)manufactured by EMP and IMP were observed.The injection molded composites exhibited the best values in the(specific)impact strength,(specific)tensile properties.IM had a greater effect on the rheological behavior of the composites than BM,and nano CaCO_(3)treatment most effectively affected the performance of the extrusion molded composites.
基金Financial Support of Oklahorna Wheat Foundation, Oklahome Wheat Commission and Oklahoma Experiment Station of Oklahoma State University.
文摘The effect of reduced glutathione (GSH) on fresh and pre-proofed frozen dough rheological properties were investigated using dynamic stress rheometry and small scale extensibility with the addition of three levels (80×10-6, 160× 10-6 and 240×10-6 GSH) and six storage times (0 and 1 day, 2, 4, 6 and 8 weeks). Three relaxation times (1, 13 and 26min) after loading the dough in the rheometer were used to determine storage (G’) and loss (G”) moduli. Correlations for G’ (r=0.678 and 0.622 at 0.05, and 10Hz, respectively) and G” (r=0.699, and 0.690 at 0.05, and 10Hz, respectively) were observed with the area under the extension curve at 26 min relaxation time. The addition of GSH to fresh dough reduced G’ (16.4% to 55.9%) and G” (13.7% to 52.2%). Freezing and frozen storage caused increase in G’ and G”. The addition of GSH reduced dough strength indicated by the reduction in maximum resistance to extension (Rmax) and the ratio of maximum resistance to extensibility (Rmax/E). The reduction in Rmax across all relaxation times ranged from 16.2% to 59.4%. An increase in dough extension (E) was observed with 240×10-6 GSH at all frozen storage and rest period times. Addition of GSH caused an increase of liquid phase (30.6% to 35.3%) in fresh dough and frozen dough (10.3% to 20.7%) after one day frozen storage. Negative correlations of water content in the solid phase with dough extensibility and area under the extensibility curve were found (r=-0.594 and-0.563, respectively, p<0.001). This suggests a loss of dough extensibility and strength as the water holding capacity of the dough components changes during frozen storage.
基金the National Natural Science Foundation of China(No.31571873)the National Key Research and Development Program(2018YFD0401001)。
文摘The rheological properties of wheat flour are very important for the production of bakery products,and the milling methods greatly influence the rheological properties.In this paper,we measured the particle size distributions,damaged starch contents,granular morphology,and pasting properties of the wheat flour,also carried out the uniaxial elongation test,the texture profile analysis,and rheological properties of the dough to evaluate effects of two milling methods,i.e.impact mill(IM)and hammer mill(HM),on the rheological properties of wheat flour and dough.The results showed that milling methods had no significant effects on flour pasting temperature(except the flour H3 obtained by HM grinding three times)and springiness of dough.Flour samples milled by IM had a lower damaged starch content,higher trough viscosity,higher final viscosity and higher values of setback compared to samples processed by HM.After repeated milling of IM,the damaged starch content of the endosperm granules could be controlled below 1%(P<0.05).There was a gap between H1 and H2 in the elastic modulus value of the non-fermented dough group,and the difference increased after fermentation,which was more obvious in the values of viscosity modulus.The more the milling times,the greater the elastic and viscosity modulus of dough of flour processed by both IM and HM.
基金supported by the Doctoral Scientific Research Start-up Foundation from Henan University of Technology (2019BS022)。
文摘The baking quality of sorghum-wheat bread is equally reliant on the quantity and the quality of protein existent in the composite flours. A lot of procedures have been proposed for expanding the use of sorghum either as a composite flour blended with wheat or potentially as a straight flour. In any case,the amount of flour that can be subbed is up to a specific degree of sorghum flour to deliver sensory attractive products. The manipulation of the chemical composition, textural properties of the sorghum kernel, and selection of a proper hybrid could proffer desirable value addition results in bread making.The quality of the flour and the adherence to acceptable flour size standards is the key to producing good quality bread. In this paper, the effects of adding sorghum flour on dough rheological properties and the quality of bread were discussed in detail.
基金financially supported by the National Natural Science Foundation of China(No.51974351No.51704322+1 种基金Major Program,No.51991361)the National Science and Technology Major Project of China(No.2016ZX05040-005)。
文摘Regulating rheological properties of water-based drilling fluids has always been a hot topic.This paper proposed a new method for regulating rheological properties of water-based drilling fluids by ultrasonic field.The experimental results showed that the ultrasound increased the viscosity and yield point of bentonite suspension by reducing the particle size of clay,destroying the network structure between clay particles,increasing the mud yield and the cation exchange capacity of bentonite,and promoting the hydration dispersion of bentonite.The change of rheological property showed a memory effect at room temperature and high temperature.Besides,the ultrasonic energy affected the network structure between clays and polymer chains,thus regulating the rheological properties of the bentonite-polymer system.For two types of drilling fluids investigated,the rheology of the poly-sulfonate drilling fluid was regulated by damaging the grid structure between additives and clays by low-power ultrasound and reducing the clay particle size by high-power ultrasound,while the rheology of the deep-water drilling fluid was mainly regulated by disentangling the spatial grid structure between additives.Additionally,ultrasound showed no effect on the lubricity,inhibition and stability of drilling fluids,which proved the feasibility of ultrasound to regulate rheological properties of water-based drilling fluids.
文摘Global ecological concerns have resulted in an interest in renewable natural materials. Composites based on high density polyethylene (HDPE), wood fiber (Veneer) and containing coupling agents like nanoclay (NC) and poly-ethylene-co-glycidyl methacrylate (PEGMA) were made by melt compounding and then injection molding. In this study, the effects of two variable parameters namely nanoclay and coupling agent on the rheological and thermal properties of wood polyethylene composites (WPECs) were investigated. The study investigates the morphology phase, rheology behaviors and thermal properties by scanning electron microscope, capillary rheometer and thermal gravimetric analyzer. The SEM micrographs of the composites showed that the outer surfaces of the wood were coated by a section of amorphous lignin. The state of dispersion in HDPE/pine/clay composites was improved by EGMA because it could interact with pine flour in addition to clay. The interaction of reinforcement with coupling agent and HDPE matrix is strong based on the observation of the fracture surface of composites when EGMA is present. However the addition of 2.5% clay slightly lowered the initial degradation temperature (Td) but did not improve the thermal stability. Obviously, all the composites materials exhibit viscoelastic values greater than those of neat HDPE.
基金supported by the National Key R&D Program of China(Grant No.2018YFB1600200)the Fok YingTong Education Foundation(Grant No.161072)+1 种基金the Youth Top-notch Talent Support Program of Shaanxi Provincethe Fundamental Research Funds for the Central Universities(Grant No.300102219317)。
文摘This work investigated the aging effects on the rheological properties of high viscosity modified asphalt(HVMA).First,the high-and low-temperature rheological properties were measured by a dynamic shear rheometer and a bending beam rheometer,respectively.The aging mechanism was then tested using an Fourier transform infrared spectroscopy and a scanning electron microscope.Besides,a study was performed to compare the aging effects on the rheological properties of HVMA,crumb rubber modified asphalt(CRMA),and neat asphalt(SK-90).The experimental results showed that the effects of the long-term aging on HVMA exceeded those of short-term aging.The complex shear modulus of the HVMA was improved by the aging in the whole frequency range.The complex shear modulus of the HVMA after the long-term aging was larger than after the short-term aging.Thus,the aging improved the high-temperature viscoelastic performance of HVMA.With a decrease in temperature from-12℃to-24℃,the low-temperature viscoelastic performance of HVMA decreased since its stiffness modulus and low continuous grading temperature increase.Both of the short-and long-term aging of HVMA were caused by an oxidation reaction,while modifier swelling also happened after long-term aging.Compared to CRMA and SK-90,aging had a limited influence on the high-and low-temperature rheological properties of HVMA.
基金financially supported by the National Natural Science Foundation of China(Nos.52104156,52074351,52004330)the Science and Technology Innovation Program of Hunan Province,China(No.2021RC3125)the Natural Science Foundation of Hunan Province,China(No.2022JJ30714)。
文摘Rod milling sand(RMS)—a coarse sand aggregate—was recycled for cemented paste backfill(CPB)for the underground mined area at the Jinchuan nickel deposit,named rod milling sand-based cemented paste backfill(RCPB).The adverse effects of coarse particles on the transportation of CPB slurry through pipelines to underground stopes resulting in weakening of the stability of the backfill system are well known.Therefore,sulfonated naphthalene formaldehyde(SNF)condensate was used for the performance improvement of RCPB.The synergistic effect of solid content(SC),lime-to-sand ratio,and SNF dosage on the rheological and physicomechanical properties,including slump,yield stress,bleeding rate,uniaxial compressive strength(UCS),as well as mechanism analysis of RCPB,have been explored.The results indicate that the effect of SNF on RCPB performance is related to the SNF dosage,lime-to-sand ratio,and SC.The slump of fresh RCPB with 0.1wt%-0.5wt%SNF increased by 2.6%-26.2%,whereas the yield stress reduced by 4.1%-50.3%,indicating better workability and improved cohesiveness of the mix.The bleeding rate of fresh RCPB decreased first and then rose with the increase of SNF dosage,and the peak decrease was 67.67%.UCS of RCPB first increased and then decreased with the increase of SNF dosage.At the optimal SNF addition ratio of 0.3wt%,the UCS of RCPB curing for 7,14 and,28 d ages increased by 31.5%,28.4%,and 29.5%,respectively.The beneficial effects of SNF in enhancing the early UCS of RCPB have been corroborated.However,the later UCS increases at a slower rate.The research findings may guide the design and preparation of RCPB with adequate performance for practical applications.
基金the financial support provided by the National Natural Science Foundation of China Project (U21A20315,21978186)the Fund for Shanxi“1331 Project” (1331)。
文摘Polypropylene(PP)grease holds great potential for special industrial applications.In this study,synthetic conditions,thickener content,and the ratio of two different molecular weight PPs were investigated systematically using a rheometer,scanning electron microscope,X-ray diffraction,Fourier transform infrared spectrometer,oscillating tribometer,and 3D surface profiler measurements.The results showed that suitable synthetic conditions are two quenching cycles,and the synthetic temperature and time is 240℃for 12 h.The rheological analysis showed that thickener content and different proportions of the two PP molecular weights have a significant influence on the rheological properties of PP grease.High molecular weight PP(H-PP)has a stronger thickening ability than low molecular weight PP(L-PP).The higher the amount of H-PP in the fixed thickener content or the higher the thickener content with a specific proportion,the higher the viscoelasticity of PP grease.The tribological performance is related to the rheological properties.The proportion of two different molecular weight PPs in the thickener content should be appropriate;excessive H-PP content leads to lubrication failure.
基金sponsored by the National Natural Science Foundation of China (Grant Nos.52178299 and 51325802).
文摘Extrudability and constructability are two important,yet contradictory issues pertaining to the construction of three-dimensional(3D)printing concrete.Extrudability is easily achieved when 3D printing cement mortar has a high water content and low cohesion,but the printed structure is easily collapsible.However,a 3D printing cement mortar with a low water content and high cohesion has a relatively stable printed structure although the cement mortar might not be extrudable.This study proposes a particle-based method to simulate 3D printing mortar extrusion and construction as an overall planning tool for building design.First,a discrete element model with time-varying liquid bridge forces is developed to investigate the microscopic effects of these forces on global rheological properties.Next,a series of numerical simulations relevant to 3D printable mortar extrudability and constructability are carried out.The study demonstrates that the effects of time-varying liquid bridge forces on rheological properties and the resulting extrudability and constructability of 3D printing mortar are considerable.Furthermore,an optimized region that satisfies both the extrusion and construction requirements is provided for 3D printing industry as a reference.
基金The work described in this paper is supported by the National Natural Science Foundation of China under Grant No.51778136Technology Research and Development Project of China Railway under No.J2019G003.
文摘High viscosity asphalt(HVA)has been a great success as a drainage pavement material.However,the larger porosity of drainage asphalt mixtures weakens the cohesion and adhesion and leads to premature rutting,water damage,spalling and cracking.The purpose of this study was to investigate the rheological properties of HVA prepared using different high viscosity modifiers through conventional tests,Brookfield viscosity tests,dynamic shear rheometer tests and bending beam rheometer tests.The conventional performance results demonstrated SBS+rubber asphalt(SRA1/2)exhibited excellent elastic recovery and low-temperature flexibility.The 60℃ dynamic viscosity results indicated TPS+rubber asphalt(TRA)had the excellent adhesion.The rotational viscosity results and rheological results indicated that SRA-2 not only exhibited excellent temperature stability and workability,as well as excellent resistance to deformation and rutting resistance,but also exhibited excellent low-temperature cracking resistance and relaxation performance.Based on rheological results,the PG classification of HVA was 16%rubber+asphalt for PG76-22,20%rubber+asphalt for PG88-22,TRA and SRA-1/2 for PG88-28.From comprehensive evaluation of the viscosity,temperature stability and sensitivity,as well as high/low temperature performance of HVA,SRA-2 was found to be more suited to the requirements of drainage asphalt pavement materials.
基金financially supported by the Thailand Science Research and Innovation(TSRI)through the Royal Golden Jubilee Ph.D.Program Scholarship(No.PHD/0058/2557)the research funding from the National Research Council and TSRI(No.RDG62T0029)financial support from the research unit in polymer rheology and processing,Thammasat University。
文摘This study investigated the effects of natural rubber(NR)and an organic peroxide on the rheological properties,mechanical properties,morphology,and bubble stability during film blowing of poly(lactic acid)(PLA).The NR and peroxide contents were varied from 0 wt%to 25 wt%and 0 wt%to 0.5 wt%,respectively.The results confirmed that the presence of well-dispersed NR could significantly improve the toughness,elongation at break,and processability of PLA films,where the optimal amount of NR was 15 wt%.For the reactive blending with peroxide,a suitable peroxide content for good film toughness and clarity was 0.03 wt%,while the higher content of 0.1 wt%could provide slightly higher processability.These contents are considered much lower than that in the PLA system(without NR),which required up to 0.5 wt%peroxide.The rheological studies indicated that the melt strength,the storage modulus(G’)and complex viscosity(η*)at low frequency could be correlated with good film blowing processability of the PLA/NR films at low gel contents.These parameters failed to correlate in the films having high gel contents as the deformation rate experienced by each test was different leading to the different levels of response to the type and amount of gels.
基金supported by the National Natural Science Foundation of China(31301593)Chinese Universities Scientific Fund(2017QC041)Research and Development Fund for University’s Doctoral Discipline of China(20130008120021).
文摘The rheological properties of flaxseed meal(FM)and Soybean Protein Isolate(SPI)extruded by the two-screw extruder under different processing conditions were investigated.Moisture,temperature,screw speed and SPI concentration were the four major factors for the extrusion process.The rheological properties of extruded products were calculated by steady state flow test,frequency sweep test and creep test.All the samples showed shear-thinning effect that is to say their apparent viscosities decreased with the increases of shear rate.The data fitted well to Power Law model.It was found that both the storage(G′)and loss modulus increased as the rise in the angular frequency(w),which also fitted well to Power Law model.The creep-recovery behavior of the samples fitted well to Burger’s model.In addition,the temperature had no significant effect on the creep recovery rate of the samples.
