The Influence of Single-Walled Carbon Nanotubes on the Aging Performance of Polymer-Modified Binders.

The use of polymer-modified binders in asphalt concrete makes it possible to increase the efficiency and durability of highways. However, at present, there is an important and unresolved problem in this area, making it impossible to fully exploit the potential of modified binders. This is a tendency of aging processes that leads to the premature destruction of the pavement. In many literary sources, it is reported that reasons are related to the peculiarity of the chemical composition and occur at the submicron level. Therefore, the influence of single-walled carbon nanotubes has been studied for a better understanding of aging processes. The aging processes of the RTFOT (rolling thin film oven test) and PAV (pressure aging vessel) modified with SBS (styrene-butadiene-styrene) polymer, single-walled carbon nanotubes, and waste industrial oil were simulated in a laboratory furnace. Microstructural features were studied using the method of infrared spectral analysis. The dependences of viscoelastic properties on the component composition of binders were investigated. The optimal content of single-walled carbon nanotubes (0.001%), SBS (styrene-butadiene-styrene) polymer (3.5%), and waste industrial oil (4%) in the binder composition was established, which synergistically improved the performance of the modified binder from PG (52-22) (performance grade) to PG (64-34). It was established that single-walled carbon nanotubes provide improvement in the durability parameter ∆Tc binder by 150%, improved relaxation properties at low temperatures, and resistance to fatigue damage.

Evaluation and Correlation Analysis of the Rheological Properties of Ground Tire Rubber and Styrene Butadiene Styrene Compound-Modified Asphalt.

With the increase in highway traffic volume, many waste tires are being produced, which puts serious pressure on the global ecological environment. Processing waste tires into powder and adding them to asphalt is an important and effective way to solve this noticeable environmental challenge. In this paper, to produce ground tire rubber (GTR) and styrene-butadiene-styrene (SBS) compound-modified asphalt, GTR was put into SBS-modified asphalt (GTRSA). Subsequently, some ordinary property tests, frequency sweep tests, and multiple stress creep recovery tests were conducted to investigate the conventional properties and rheological properties of GTRSA. Moreover, the 2S2P1D (two springs, two parabolic elements, and one dashpot) model was adopted to analyze the consequences of adding GTR content on the rheological properties of GTRSA. Finally, the Pearson correlation coefficient was employed to reveal the connection between the conventional properties and the rheological properties. The results show that GTR has a great impact on improving the rutting resistance, thermo-sensitive performance, shear resistance capability, stress sensitivity, and creep recovery performance of GTRSA. Adding 20% GTR can improve the creep recovery rate to 80.8%. The 5 °C ductility index suggests that GTR makes a difference to the low-temperature properties. The rheological properties and conventional properties had a strong linear link.

Effect of Kaolinite and Cloisite Na+ on Storage Stability of Rubberized Binders.

This study aimed to evaluate the impact of a two-step modification process involving kaolinite and cloisite Na+ on the storage stability of rubberized binders. The process involved the manual combination of virgin binder PG 64-22 with crumb rubber modifier (CRM), which was heated to condition it. The preconditioned rubberized binder was then modified for two hours at a high speed of 8000 rpm using wet mixing. The second stage modification was performed in two parts, with part 1 using only crumb rubber as the modifier and part 2 involving the use of kaolinite and montmorillonite nano clays at a replacement percentage of 3% to the original weight of the binder along with the crumb rubber modifier. The Superpave and multiple shear creep recovery (MSCR) test methods were used to calculate the performance characteristics and separation index % of each modified binder. The results showed that the viscosity properties of kaolinite and montmorillonite improved the performance class of the binder, with montmorillonite demonstrating greater viscosity values than kaolinite even at high temperatures. Additionally, kaolinite with rubberized binders showed higher resistance to rutting, and the % recovery value from multiple shear creep recovery testing indicated that kaolinite with rubberized binders was more effective than montmorillonite with rubberized binders, even at higher load cycles. The use of kaolinite and montmorillonite reduced phase separation between the asphaltene phase and rubber-rich phase at higher temperatures, but the performance of the rubber binder was affected by higher temperatures. Overall, kaolinite with the rubber binder generally demonstrated greater binder performance.

Effect of retrograded starch with different amylose content on the rheological properties of stored yogurt.

Resistant starch (RS) promotes health benefits; however, when added to foods, it could change the rheological properties. The effect of adding different concentrations (2.5, 5, 7.5, and 10%) of retrograded corn starch with 27% (RNS) or 70% (RHS) amylose content on the properties of yogurt was evaluated through measurements of flow behavior and gel structure. Syneresis and resistant starch content were also assessed. Results were analyzed using multiple regression to describe the effect of starch concentration and storage time on the properties of yogurt added with RNS or RHS. Syneresis was reduced, RNS reinforced the structure increasing the water absorption capacity and the consistency index; meanwhile, RHS provided a yogurt containing up to 10 g of RS in 100 g of sample, allowing obtaining a functional dairy product. Creep-recovery test showed that adding RNS or RHS favored the matrix conformation, and the yogurt samples were able to recover. The final product behaved like a solid material with a firmer and more stable gel structure, resulting in a strengthened gel without weakening the yogurt structure, showing a characteristic like Greek-style or stirred yogurt depending on the type and concentration of retrograded starch. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-023-05735-x.

Experimental Study on Creep-Recovery Behavior of Polyphosphoric Acid (PPA) Modified Asphalt Binders under Multiple Factors.

The polyphosphoric acid (PPA) modified asphalt binder is a potential choice as one of the pavement materials for its excellent high-temperature performance and low cost. To further analyze the influences of temperature and load on the service life of pavement from the perspective of deformation behavior, six kinds of asphalt binders with different PPA dosages were prepared for Multiple Stress Creep and Recovery (MSCR) tests at five temperature levels. The deformation behavior is investigated by basic deformation parameters, rheological simulation, and energy parameter changes. The results show that the percent recovery (R) drops sharply while non-recoverable creep compliance (Jnr) goes up slightly with the increase in temperature. Three-element model, composed by E1, η1, and η2, can be used to describe the creep behavior. PPA-modified asphalt binder exhibits nonlinear creep behavior, and the logarithmic model can simulate recovery behavior better than the power-law model. Stored energy and dissipated energy can characterize the change of energy in the creep process under different conditions and show a significant correlation to deformation parameters. It is concluded that the elastic component of asphalt binders is increased by PPA, which is beneficial to the improvement of the deformation resistance and recovery capacity of asphalt binders. The recommended dosage of PPA is 1.5%. This investigation is conducive to a better understanding of the deformation behavior of PPA-modified asphalt binders and provides a reference for its engineering applications.

Effect of Fiber Reinforcement on Creep and Recovery Behavior of Cement-Emulsified Asphalt Binder.

In order to evaluate and improve the deformation behavior of cement-emulsified asphalt binder (CA) in cement-emulsified asphalt mixture, this study investigated the reinforcement of small additions of fibers (2%, 4%, and 6% addition by mass of cement) on the deformation resistance of CA. A repeated creep recovery test was implemented that measures the recovery rate of creep deformation and accumulated strain. Further, an improved piecewise curve-fitting method was used to determine the parameters of Burgers model, then the creep compliances were fitted and calculated. The results show the repeated creep recovery test to be a suitable method for obtaining useful information about creep and recovery deformation of fiber-reinforced CA. The influence of fiber types and dosages on the deformation recovery ability is determined based on the creep recovery ratio and accumulated strain. The improved piecewise curve-fitting method has high accuracy. Thereafter, the reinforcement effect was analyzed through the evolution of creep compliance under loading. Therefore, this paper can provide a reference for enhancing the properties of cement-emulsified asphalt mixture by maximizing the fiber reinforcement.

Engineering a semi-interpenetrating constructed xylan-based hydrogel with superior compressive strength, resilience, and creep recovery abilities.

Recent advances in the area of hydrogel synthesis have been directed to enhance the mechanical properties and biocompatibility, which are critical in their use as functional biomaterials. In this work, a green and facile method is introduced to produce a hydrogel based on xylan, a plant-based heteropolysaccharide, that is shown to successfully form hydrogen-bonded, semi-interpenetrating polymer networks with polyvinyl alcohol. Upon crosslinking with sodium trimetaphosphate, the obtained hydrogels achieved an exceptional compressive strength (up to 84.2 MPa at a fracture strain of 90 %), which surpasses any polysaccharide-based hydrogels reported so far. The hydrogels were further shown to have high degradation temperature (350-370 °C), to be mechanically resilient with a form and creep recovery of 95 % (78 % stress after 1000 cycles under 30 % strain) and 98 % in height, respectively. All materials used in the preparation of the hydrogels were non-toxic and biocompatible, which makes the synthesized hydrogels suitable potential candidates for soft-tissue engineering and biomedical applications.

Rheological Evaluation of Softened Binders Blended with Aged Asphalt Selected with a High-Temperature Mixing Chart.

Reclaimed asphalt pavements (RAP) provide economic and environmental benefits. In recent decades, their use has increased, but rheological properties are affected by RAP aging, increasing stiffness, cracking, and susceptibility to water. To counteract these effects, rejuvenating agents are used, but they must be properly dosed to design quality mixtures. Therefore, different binders were analyzed, including virgin binder (VBB), binder modified by SBS polymer (MB), AC-RAP, binder softened using a rejuvenating agent, and binders softened with doses (15%, 30%, and 45%) of AC-RAP. The rheological properties were evaluated by dynamic shear rheometry (DSR) and beam-bending rheometry (BBR) tests, while the linear amplitude sweep (LAS) test was used to measure fatigue cracking and the multiple stress creep recovery (MSCR) test was used to measure rutting. A mixing chart was constructed based on a high temperature AC-RAP to satisfy the performance grade (PG 76-22). The results showed that softened binders become flexible, but when AC-RAP is added, they turn stiff and behave better than MB. Moreover, combining a rejuvenating agent and AC-RAP reduces the aging stiffness of RAP, improving its rheological properties without compromising the rutting or cracking resistance.

Texture and viscoelastic characteristics of silver carp (Hypophthalmichthys molitrix) surimi affected by combination of washing regimes and hydrogen peroxide.

This study aimed to apply H2 O2 at different concentrations in combination with mince:water (M:W) ratios and different washing cycles (WCs) to produce surimi gel from silver carp without compromising its quality characteristics. Color, texture, microstructure, and rheological properties of surimi gels were investigated. Water holding capacity, texture profile, and gel strength showed a greater dependency on number of WCs than the M:W ratios and percentage of H2 O2 (p < .05), that is, higher WCs, firmer surimi gel. Accordingly, T2 (one WC, 2% H2 O2 , 1:3), T10 (two WC, 1% H2 O2 , 1:2), and T16 (three WC, 1% H2 O2 , 1:2) treatments resulted the most cohesive and resilient surimi compared with the rest (p < .05), confirmed by scanning electron microscopy images. However, all treated fish mince samples with H2 O2 , resulted in a surimi gel with lower texture quality compared with the control surimi prepared by conventional washing process without H2 O2 (p < .05). A temperature sweep test was conducted based on the linear viscoelastic region stress and frequency values and the aforementioned surimi gels exhibited an obvious valley shape pattern at temperature range of 48-62°C. In the creep-recovery test, the Burgers model satisfactorily described the internal structure of the surimi gel samples as the lowest deformation belonged to the control samples followed by T2. However, after 300 s strain, neither of surimi gels were fully recovered their original shape. Altogether, further studies are needed to clarify the effects of H2 O2 in reduction of WCs, without significantly affecting the textural and rheological properties of resultant surimi gel.

Effect of Fenugreek fiber on Rheological and chapati making quality of whole wheat flour.

Increase in awareness of consumers and demand has led to the development of various fibre rich food products from different fiber source. In the present work novel roller milled fenugreek fiber rich fraction (FFRF) rich in galactomannans was used for the development of high fiber chapati. Farinograph water absorption and dough stability increased with increase in the addition of FFRF in blends. The creep measurement results showed reduction in the maximum creep compliance and viscoelastic compliance while the zero shear viscosity showed the increasing trend with the increase in the addition of FFRF. The pliability of chapatis significantly decreased on addition of FFRF. The sensory evaluation concluded that the chapati with 10% FFRF is acceptable. The shear force value of chapatis prepared from the control and WWF-FFRF blends were decreased as the storage time increased showing brittleness in the chapatis. The micrographs of an outer layer of chapati (crust) showed partially gelatinized starch. The crumb micrographs of the WWF-FFRF blends chapatis showed large and small starch granules coated with galactomannans gums, and this coating increased with increased addition of FFRF. The composition of 10% fenugreek fiber chapati contained higher amount of minerals, insoluble and soluble dietary fiber compared to that of control sample. The in vitro starch digestibility of formulated chapati showed significant decrease in the values.

A Promising Therapeutic Soy-Based Pickering Emulsion Gel Stabilized by a Multifunctional Microcrystalline Cellulose: Application in 3D Food Printing.

The feasible application of additive manufacturing in the food and pharmaceutical industries strongly depends on the development of highly stable inks with bioactive properties. Surface-modified microcrystalline cellulose (MCC) shows the potential of being a useful particulate (i.e., Pickering)-type emulsifier to stabilize emulsions. To attain desired therapeutic properties, MCC can also be tuned with cationic antimicrobial compounds to fabricate an antimicrobial printable ink. However, due to the formation of complex coacervates between the two, the Pickering emulsion is very susceptible to phase separation with an insufficient therapeutic effect. To address this drawback, we reported a green method to produce antioxidant and antimicrobial three-dimensional (3D)-printed objects, illustrated here using a printable ink based on a soy-based particulate-type emulsion gel stabilized by a surface-active MCC conjugate (micro-biosurfactant). A sustainable method for the modification of MCC is investigated by grafting gallic acid onto the MCC backbone, followed by in situ reacting via lauric arginate through Schiff-base formation and/or Michael-type addition. Our results show that the grafted micro-biosurfactant was more efficient in providing the necessary physical stability of soy-based emulsion gel. The grafted micro-biosurfactant produced a multifunctional ink with viscoelastic behavior, thixotropic property, and outstanding bioactivities. Following the 3D printing process, highly porous 3D structures with a more precise geometry were fabricated after addition of the micro-biosurfactant. Dynamic sensory evaluation showed that the micro-biosurfactant has a remarkable ability to improve the temporal perceptions of fibrousness and juiciness in printed meat analogue. The results of this study showed the possibility of the development of a therapeutic 3D-printed meat analogue with desired sensory properties, conceiving it as a promising meat analogue product.

Rheological properties and microstructure of a novel starch-based emulsion gel produced by one-step emulsion gelation: Effect of oil content.

A high elastic starch-based emulsion gel was fabricated by one-step heat-set gelation of the emulsion stabilized by octenylsuccinate starch for the first time. The effect of oil content on the linear and nonlinear rheological behavior and microstructure of the novel emulsion gel was investigated. The role of oil as inactive or active filler in the system shifted depending on content. The oil at low content of 10% did not integrate well into gel matrix and manifested as defects to gel network, playing as inactive filler, which was further confirmed by its decreased rheological modulus and viscoelastic properties compared with pure starch gel. Increasing the oil from 20% to 70% enhanced the gel strength related to a denser packing of oil droplets and starch aggregation, performing as active filler. This work provided a new strategy for structuring liquid oil, and the gel could find applications in food structuring and fat replacer.

Rheological properties and critical concentrations of a hyperbranched polysaccharide from Lignosus rhinocerotis sclerotia.

The application of polysaccharides in the food industry mainly depends on their rheological properties and the polysaccharides in different concentration regions exhibit different rheological properties due to the interactions between polymer chains. Hence, this work investigated the concentration-dependent rheological behavior of Lignosus rhinocerotis polysaccharide (LRP) in water and determined the critical concentrations. The intrinsic viscosity of LRP was 378 ± 32 mL/g and the LRP exhibited more apparent shear-thinning behavior with increasing concentration. The LRP critical overlap and aggregation concentration in water was ~ 2.5 mg/mL, implicating the formation of hydrophobic regions may result from the aggregation and overlap between hyperbranched LRP molecules. The LRP/water system showed higher storage modulus than loss modulus with slight frequency dependence at the concentration of 15 mg/mL, exhibiting the structured liquid behavior. When the concentration increased from 10 mg/mL to 30 mg/mL, the compliance recovery percentage value increased from 58.51% to 92.30%, indicating the formation of a strong gel network in the LRP/water system. Furthermore, the micro-rheological test revealed that the LRP/water system exhibited a concentration-dependent increase in elasticity and viscosity and deterioration in fluidity.

Creep-recovery behaviors of articular cartilage under uniaxial and biaxial tensile loadings.

Creep deformation in cartilage can be observed under physiological loads in daily activities such as standing, single-leg lunge, the stance phase of gait. If not fully recovered in time, it may induce irreversible damage in cartilage and further lead to early osteoarthritis. In this study, 36 cruciform-shape samples in total from 18 bulls were employed to conduct the uniaxial and biaxial creep-recovery tests by using a biaxial cyclic testing system. Effects of stress level (σ = .5, 1.0, 1.5 MPa) and biaxial stress ratio (B = 0, .3, .5, 1.0) on creep-recovery behaviors of cartilage were characterized. And then, a viscoelastic constitutive model was employed to predict its creep-recovery behaviors. The results showed that the creep strain and its three components, namely instantaneous elastic strain, delayed elastic strain and viscous flow strain, increase with the increasing stress level or with the decreasing biaxial stress ratio. Compared with uniaxial creep-recovery, biaxial creep-recovery exhibits a smaller creep strain, a faster recovery rate of creep strain and a smaller residual strain. Besides, the built viscoelastic model can be used to describe the uniaxial creep-recovery behaviors of cartilage as a good correlation between the fitted results and test results is achieved. The findings are expected to provide new insights into understanding normal joint function and cartilage pathology.

Impact of Roasted Yellow Split Pea Flour on Dough Rheology and Quality of Fortified Wheat Breads.

Roasted yellow split pea (YSP) flours were used to substitute wheat flour, at 10-20% (flour basis) in wheat bread formulations. Rheometry showed that roasted YSP flour addition increased elasticity and resistance to deformation and flow of the composite doughs, particularly at 20% substitution; instead, at 10% addition (either raw or roasted YSP flour), there were no effects on dough rheology and bread textural properties. Breads fortified with roasted YSP flour at levels >10% exhibited lower loaf-specific volume and harder crumb compared to control (bread without YSP flour). Moreover, only breads with 20% roasted YSP flour displayed a significantly higher staling extent and rate, compared to control, as assessed by large deformation mechanical testing and calorimetry (starch retrogradation) of crumb preparations. This formulation also showed a large increase in ß-sheets and ß-turns at the expense of α-helix and random coil conformations in protein secondary structure as assessed by FTIR spectroscopy. Roasting of YSP effectively masked the "beany" and "grass-like" off-flavors of raw YSP flour at 10% substitution. Overall, roasted YSP flour at the 10% level was successfully incorporated into wheat bread formulations without adversely affecting dough rheology, bread texture, and shelf-life, resulting in final products with a pleasant flavor profile.

Homogeneity and Viscoelastic Behaviour of Bitumen Film in Asphalt Mixtures Containing RAP.

This article discusses the phenomenon of fresh and RAP binders miscibility and presents test results of bitumen film properties from specially prepared asphalt mixtures. The miscibility of a fresh binder and a RAP binder still has not been fully recognised. The aim of this study was to determine the homogeneity level of the bitumen film based on viscoelastic assessment. In addition, an attempt was made to assess the impact of fresh binder on the binders blending degree. The study included assessment of homogeneity of bitumen film comprising various types of bituminous binders. The assessment was conducted on the basis of tests in the dynamic shear rheometer regarding rheological properties of the binders recovered from specific layers of the bitumen film using a staged extraction method. A complex shear modulus as a function of temperature, an elastic recovery R and a non-recoverable creep compliance modulus JNR from MSCR test were determined. The conducted statistical analyses confirmed the significant impact of the type of fresh binder on the blending degree. Regressive dependencies have been set between the differences of the complex shear modulus of the binders subject to mixing and differences of the complex shear modulus of binders from the internal and external layer of the bitumen film comprised of those binders. It was found that there is no full blending of fresh hard bitumen-simulated binder from RAP, which results in non-homogeneity of the bitumen film.

Characterization of Desulfurized Crumb Rubber/Styrene-Butadiene-Styrene Composite Modified Asphalt Based on Rheological Properties.

With the growing interest in bituminous construction materials, desulfurized crumb rubber (CR)/styrene-butadiene-styrene (SBS) modified asphalts have been investigated by many researchers as low-cost environmental-friendly road construction materials. This study aimed to investigate the rheological properties of desulfurized CR/SBS composite modified asphalt within various temperature ranges. Bending beam rheometer (BBR), linear amplitude sweep (LAS), and multiple stress creep recovery (MSCR) tests were performed on conventional CR/SBS composite modified asphalt and five types of desulfurized CR/SBS modified asphalts. Meanwhile, Burgers' model and the Kelvin-Voigt model were used to derive nonlinear viscoelastic parameters and analyze the viscoelastic mechanical behavior of the asphalts. The experimental results indicate that both the desulfurized CR/SBS composite modifier and force chemical reactor technique can enhance the crosslinking of CR and SBS copolymer, resulting in an improved high-, intermediate-, and low-temperature performance of desulfurized CR/SBS composite modified asphalt. Burgers' model was found to be apposite in simulating the creep stages obtained from MSCR tests for CR/SBS composite modified asphalts. The superior high-temperature performance of desulfurized CR/SBS modified asphalt prepared with 4% SBS, 20% desulfurized rubber, and a force chemical reactor time of 45 min contributes to the good high-temperature elastic properties of the asphalt. Therefore, this combination is recommended as an optimal preparation process. In summary, the desulfurization of crumb rubber and using the force chemical reactor technique are beneficial to composite asphalt performance and can provide a new way of utilizing waste tire rubber.

Extrusion of wheat gluten-peanut oil complexes and their rheological characteristics.

In order to clarify the effects of extrusion treatment on the processing properties of extrudates, providing a theoretical basis for the production of gluten-based extrudates with favorable sensory quality. This study examined the effects of various extrusion temperatures on the rheological properties of wheat gluten-peanut oil complexes (WPE) and wheat gluten (WG). At the extrusion temperature conditions of this study, the dynamic moduli of gluten in WG and WPE reached the maximum, and the creep strain reached a minimum at 160 °C. Extrusion treatment resulted in the decrease in ß-sheet and α-helix content and an increase in the amount of ß-turns and random coils. The secondary structural changes and increase in the number of disulfide bonds led to gluten aggregation, thus affecting their rheological properties. These results enhance our understanding of the variations in the rheological properties of extrudates and promote the potential application of gluten-based complexes in extrusion.

Coffee Cherry Pulp by-Product as a Potential Fiber Source for Bread Production: A Fundamental and Empirical Rheological Approach.

Effects of substituting of wheat flour with coffee cherry pulp powder (CCPP) (coffee by-product as fiber source) at 0, 1.2, 2.3, and 4.7% dry basis (0, 1.25, 2.5, and 5% wet basis) on dough and gluten rheological properties and baking quality were investigated. Rheological properties were analyzed during mixing, compression recovery, and creep-recovery. A rheological approach was adopted to study the viscoelasticity of dough enriched with fiber. The data obtained were analyzed with the Kelvin-Voigt model and the parameters were correlated to bread volume and crumb firmness to assess the effect of incorporating CCPP. A decrease in gluten's elastic properties was attributed to the water-binding and gelling properties of CCPP. Stiffness of dough and crumb firmness increased as the level of CCPP increased and bread volume decreased. Stiffer dough corresponded with lower compliance values and higher steady state viscosity compared to the control. A follow-up study with 5% CCPP and additives is recommended to overcome the reduction in elastic recovery and bread volume.

Multi-scale semi-analytical model for fatigue life prediction of trans-tibial prosthetic sockets.

The trans-tibial socket is an essential component of the prosthesis that connects it to the residual limb. Socket misalignments and permanent deformations reduce the comfort of the amputee. In order to forestall such issues, sufficient information about the socket lifespan needs to be acquired, which is fairly difficult given the lack of calculation methods that estimate the fatigue life in the literature. In this paper a semi-analytical model is proposed based on experimental results. It highlights the effects of the amputee average daily walking time on the socket fatigue life. A proportionality relationship is demonstrated linking the Burgers model parameters at the structural scale to those at the macroscopic scale. Hence, it becomes possible to evaluate the permanent deformation that induces a misalignment in the socket. These results are useful for the designers to predict the fatigue life of the socket, and also for clinicians to monitor the mechanical degradation of the trans-tibial socket and schedule maintenance or replacement.