Search Results (48)

Bio-based polyurethane asphalt binder (PUAB) derived from castor oil (CO) is environmentally friendly and exhibits extended allowable construction time. However, CO imparts inherently poor mechanical performance to bio-based PUAB. To address this limitation, attapulgite (ATT) with fibrous nanostructures was incorporated. The effects of ATT on bio-based PUAB were systematically investigated, including cure kinetics, rotational viscosity (RV) evolution, phase-separation microstructures, dynamic mechanical properties, thermal stability, and mechanical performance. Experimental characterization employed Fourier transform infrared spectroscopy, Brookfield viscometry, laser scanning confocal microscopy, dynamic mechanical analysis, thermogravimetry, and tensile testing. ATT incorporation accelerated the polyaddition reaction conversion between isocyanate groups in polyurethane (PU) and hydroxyl groups in ATT. Paradoxically, it reduced RV during curing, prolonging allowable construction time proportionally with clay content. Additionally, ATT’s compatibilizing effect decreased bitumen particle size in PUAB, with scaling proportionally with clay loading. While enhancing thermal stability, ATT lowered the glass transition temperature and damping properties. Crucially, 1 wt% ATT increased tensile strength by 71% and toughness by 62%, while maintaining high elongation at break (>400%). The cost-effectiveness and significant reinforcement capability of ATT make it a promising candidate for producing high-performance bio-based PUAB composites. Full article

Rubber powder asphalt has been widely studied due to its favorable temperature sensitivity and fatigue resistance. However, because rubber powder does not easily swell in asphalt, it leads to poor storage stability and high viscosity, limiting its large-scale application. In this study, modified asphalt was prepared using desulfurized rubber powder (DRP) and styrene-butadiene-styrene (SBS) modifiers, aiming to identify the optimal formulation for enhanced performance. It was hypothesized that the combined use of DRP and SBS would produce synergistic effects, improving the overall mechanical and rheological properties of the asphalt. To test this, the effects of this composite modification were evaluated using Marshall tests (penetration, softening point, ductility, elastic recovery, and Brookfield viscosity) and Superpave tests (shear modulus, high-performance grade, rutting factor, fatigue factor, and creep and recovery). Additionally, moisture susceptibility, high-temperature stability, low-temperature cracking resistance, and fatigue resistance at the mixture level were assessed. Performance was evaluated according to the Chinese standard JT/T 798-2019 for rubberized asphalt using reclaimed tire rubber. Results show that DRP-modified asphalt demonstrates excellent temperature sensitivity, rutting resistance, deformation resistance, and fatigue performance. However, an excessive amount of DRP increases Brookfield viscosity, which negatively affects the workability of the asphalt binder. The addition of SBS further improves the softening point, ductility, and deformation recovery of the binder. Considering cost-effectiveness and overall performance, the optimal formulation was determined to be 25% DRP and 1% SBS. At this dosage, all performance indicators met the required standards. The rotational viscosity at 180 °C was approximately 35% lower than that of conventional rubber powder–modified asphalt, while the high-temperature rutting factor and fatigue resistance at medium-to-low temperatures outperformed those of SBS-modified asphalt. The mixture test results reveal that the gradation has an impact on the performance of the obtained mixture, but overall, the DRP-SBS composite-modified asphalt mixture has significant advantages in terms of performance and cost-effectiveness. Full article

This study investigates the stiffening phenomena caused by aging and low-dosage Kraft lignin addition on a soft bitumen (PG58S–28)- used in cold climate regions. Through a combination of physico-chemical and rheological analyses, including Fourier-transform infrared spectroscopy (FTIR), Brookfield rheometer viscosity (BRV), dynamic shear rheometer (DSR), multiple stress creep recovery (MSCR), bending beam rheometer (BBR), and complex shear modulus (G*) tests, the impacts of lignin modification and thermo-oxidative aging are evaluated. In particular, the anti-aging potential of lignin is scrutinized. The results indicate that while the carbonyl index effectively tracks bitumen aging, the sulphoxide index is less reliable due to high initial S=O bond content in Kraft lignin and greater repeatability variability. Standard rheological tests (BRV, DSR, MSCR, and BBR) show that long-term aging significantly increases bitumen stiffness, while lignin modification leads to a moderate stiffening effect but does not exhibit any noticeable anti-aging properties. The G* analysis confirms that aging strongly influences bitumen rigidity, particularly at low and intermediate equivalent frequencies, while lignin acts similarly to an inert filler, with minimal effects on linear viscoelastic (LVE) behaviour. Overall, the study concludes that the addition of Kraft lignin at low dosage does not alter the fundamental aging mechanisms of bitumen, nor does it provide significant antioxidant benefits. These findings contribute to the ongoing discussion on bio-based bitumen modifiers and their role in sustainable pavement materials. Full article

This study aims to address the limited understanding of wash oil degradation in benzene units by analysing changes in the composition and properties of fresh and operating oils from different manufacturers. The findings will provide insights into the degradation pathways and stability of these oils. Gas chromatography/mass spectrometry was used to analyse the provided samples, and the dynamic viscosity of the oils was determined using a Brookfield LV DV2T rotational viscometer. During operation, the “heavy” oil (HO) becomes less volatile, while the ”light” oil (LO) becomes slightly more volatile. The viscosity of the HO increases 1.25 times during operation. The LO is characterised by a higher total concentration of alkyl derivatives (48 wt.% compared to 44 wt.% for the HO). LO is enriched with naphthalene and indene, while HO loses 1- and 2-methylnaphthalenes and shows an increase in the concentrations of dibenzofuran, fluorene, anthracene, and phenanthrene. The oxidation products of LO include oxidised alkyl groups, while HO shows oxidised non-substituted hydrocarbons. The practical value of such studies lies in guiding the selection of fresh oil under current operating conditions. LO is more resistant to degradation as an absorbent than heavier wash oil. Full article

In order to study the effect of a warm-mix agent on the compaction characteristics of an anti-rutting asphalt mixture, this study compared the compaction temperature of an anti-rutting asphalt mixture with different warm-mix-agent contents from two aspects: asphalt viscosity and asphalt mixture voids. Based on the rheological properties of asphalt, the optimal content of the anti-rutting agent was first determined as 6% by the weight of asphalt. Four warm-mix-agent contents of 0% (control group), 1%, 2%, and 3% were designed. The viscosity–temperature curve of the warm-mix anti-rutting modified asphalt was obtained by the Brookfield viscosity tests. After that, AC-20 standard Marshall specimens were prepared to conduct a series of consecutive temperature compaction tests. The voids were calculated based on the bulk density of the specimen measured by the saturated surface-dry method. Industrial Computerized Tomography (CT) was employed to further quantify the internal voids. Two voids–compaction temperature curves were constructed based on the saturated surface-dry and CT results, respectively. The comparative results show that significant differences exist between the compaction temperatures obtained from the three curves. The viscosity–temperature curve shows that when the warm-mix agent is increased from 0% to 3%, the compaction temperature only declines about 7.9%. However, the voids–compaction temperature curves from saturated surface-dry and CT, respectively, indicate a temperature decrease of 22.7% and 19.2%. This is because a warm-mix agent will interact with asphalt, resulting in a decrease in asphalt intermolecular adsorption, whereas an anti-rutting agent mixed with asphalt will increase the degree of cross-linking and aggregation between asphalt molecules. Both additions have a certain impact on the viscosity of the asphalt binder; thus the traditional method of using the asphalt viscosity–temperature curve to determine the compaction temperature of warm-mix anti-rutting asphalt mixture has become ineffective. It is suggested to use the equal voids method to determine the compaction temperature of warm-mix anti-rutting asphalt mixtures. Full article

In order to reduce the amount of diluent in a diluted asphalt mixture, this study developed a cold patch asphalt (CPA) for repairing pavement potholes by using a mixture of treated biodiesel and diesel as the diluent. The effects of biodiesel on the performance of the cold patch asphalt mixture (CPAM) during the construction process were investigated through Brookfield rotational viscosity tests, adhesion tests, and FTIR (Fourier transform infrared spectroscopy) analyses. At the same time, the effect of biodiesel on the performance of the CPAM was analyzed by combining the strength growth test, rutting test, and water-soaked Marshall test of CPAMs. The test results show that the construction performance of the CPAM can be significantly improved by adding pretreated biodiesel. Under the same amount of diluent, the strength and high-temperature performance of the asphalt mixture diluted with biodiesel were significantly improved compared to that with diesel as the diluent. The optimal high-temperature performance reached 9027 (times/mm), representing an approximate increase of 94.7% compared to 4636 (times/mm) when only diesel was used as the diluent. When the biodiesel content increased from 10% to 40%, the residue stability improved from 85.9% to 91.3%. The corresponding 0.5 h Marshall stability increased from 5.59 kN to 8.1 kN, while the 48 h Marshall stability rose from 4.8 kN to 7.39 kN. All tests met the requirements for hot mix asphalt. Full article

In order to explore the feasibility and efficacy of reed-fiber-modified bitumen (RFMB), three lengths and three dosages of reed fibers were selected to modify bitumen and bituminous mortar, while the physicochemical properties of RFMB and RFMB mortar were analyzed. In this work, FTIR spectroscopy was employed to characterize the chemical impact of fiber on bitumen. The viscidity and rheology of RFMB and the tensile strength of RFMB mortar were evaluated using a Brookfield viscometer, dynamic shear rheometer, and monotonic tensile test. The results showed that adding fibers primarily affects the physical structure rather than the chemical composition of bitumen, confirmed by FTIR spectroscopy. RFMB viscosity increased with higher fiber dosage and fiber length. Rheological evaluations showed an enhanced complex shear modulus for RFMB, suggesting improved performance at higher temperatures but increased stiffness at lower temperatures, with the latter indicating reduced flexibility. RFMB also demonstrated superior fatigue and rutting resistance, albeit with compromised stress sensitivity. Tensile tests on RFMB mortar highlighted significant improvements, especially with longer fibers, while shorter 0.4 mm fibers showed modest reinforcement effects, possibly due to uneven distribution during sample preparation. Full article

The performance and phase-separated microstructures of epoxy asphalt binders greatly depend on the concentration of epoxy resin or bitumen. In this paper, the effect of the epoxy resin (ER) concentration (10–90%) on the viscosity, thermo-mechanical properties, and phase-separated morphology of warm-mix epoxy asphalt binders (WEABs) was investigated using the Brookfield rotational viscometer, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and laser scanning confocal microscopy (LSCM). Due to the high reactivity of epoxy resin, the viscosity of WEABs increases with time. Furthermore, the initial viscosity of WEABs decreases with the ER concentration. Depending on the ER concentration, the viscosity–time behavior of WEABs is divided into three stages: slow (10–40%), fast (50–80%), and extremely slow (90%). In the slow stage, the viscosity slightly increases with the ER concentration, while the fast stage shows an opposite trend. DSC and DMA results reveal that WEABs with 10–80% ER exhibit two glass transition temperatures (T_gs) for cured epoxy resin and bitumen. Moreover, the T_gs of epoxy resin and bitumen increase with the ER concentration. However, WEAB with 90 % ER has only one T_g. LSCM observation shows that phase separation occurs in all WEABs. For WEABs containing 10–40% ER, spherical epoxy particles act as the discontinuous phase and disperse in the continuous bitumen phase. However, in WEABs with 50–90% ER, phase inversion takes place. Contrarily, bitumen particles disperse in the continuous epoxy phase. The damping properties of WEABs with the continuous epoxy phases increase with the ER concentration, while the crosslinking density shows an opposite trend. The occurrence of phase inversion results in a sharp increase in the tensile strength of WEABs. For WEABs with the continuous epoxy phases, the elongation at break increases with the ER concentration. The toughness first increases and then decreases with the ER concentration. A maximum toughness value shows at 70% ER. Full article

To study the variation laws and effects of asphalt mastic under the cooperative interaction of different temperatures and humidities, cyclic conditions for different temperature ranges were set to conduct indoor experimental simulations of thermal–humidity coupling cycles. Firstly, the macroscopic performance changes in styrene butadiene styrene polymer (SBS)-modified asphalt mastic were evaluated by the penetration test, softening point test, ductility test, Brookfield rotational viscosity test, and double-edge notched tensile (DENT) test; then, the mechanism of performance changes was explored from the perspective of chemical composition by combining this with Fourier transform infrared spectroscopy (FTIR). The research results show that with the increase in thermal–humidity coupling cycles, SBS-modified asphalt mastic exhibited aging phenomena such as hardening and embrittlement, and its macroscopic performance deteriorated; under the same test conditions, the interval with a higher temperature difference had a greater impact on the performance of the mastic; the sulfoxide index (I_S=O) of SBS-modified asphalt mastic increases after thermal–humidity coupling cycles, while the isoprene index (I_B) decreases. Full article

To develop a cost-effective, high-viscosity asphalt for porous asphalt pavement, we utilized SBS, tackifier, and solubilizer as the main raw materials, identified the optimal composition through an orthogonal experiment of three factors and three levels, and prepared a low-cost high-viscosity asphalt. We compared its conventional and rheological properties against those of rubber asphalt, SBS modified asphalt, and matrix asphalt, employing fluorescence microscopy and Fourier transform infrared spectroscopy for microstructural analysis. The results indicate that the optimal formula composition for high-viscosity asphalt was 4–5% styrene-butadiene-styrene (SBS) + 1–2% tackifier +0–3% solubilizer +0.15% stabilizer. The components evenly dispersed and the performances were enhanced with chemical and physical modification. Compared with SBS modified asphalt, rubber asphalt, and matrix asphalt, the softening point, 5 °C ductility, and 60 °C dynamic viscosity of high-viscosity asphalt were significantly improved, while the 175 °C Brookfield viscosity was equivalent to SBS modified asphalt. In particular, the 60 °C dynamic viscosity reaches 383,180 Pa·s. Rheological tests indicate that the high- and low-temperature grade of high-viscosity asphalt reaches 88–18 °C, and that high-viscosity asphalt has the best high-temperature resistance to permanent deformation and low-temperature resistance to cracking. It can save about 30% cost compared to commercially available high-viscosity asphalt, which is conducive to the promotion and application of porous asphalt pavement. Full article

Cleaning products are often formulated as mixtures of surfactants because the properties of surfactant mixtures are easier to adjust than those of a single surfactant. Therefore, it is of great significance to study the phase diagram of surfactant mixtures. In this paper, the phase behavior of the alkyl ethoxysulfate (AES)/cocamidopropyl betaine (CAPB)/H₂O ternary system was investigated at room temperature using polarizing optical microscopy (POM) and small angle X-ray scattering (SAXS), and the identified phases of the samples with various compositions were used to construct the ternary phase diagram of the AES/CAPB/H₂O system which contains normal micellar phase (L₁), normal hexagonal phase (H₁), lamella phase (Lα), and one transition region (L₁ → H₁). The viscosity distribution of the AES/CAPB/H₂O system was determined by a Brookfield DV2T touch screen viscometer. In addition, the effects of the weight percentage of CAPB and salts on the viscosity and rheological properties of the AES/CAPB/H₂O system were also investigated. This work not only enriches the phase diagram of surfactant systems, but also has important guiding significance for the design and development of cleaning products. Full article

This paper presents studies on the influence of the chemical structure of (meth)acrylic monomers on the properties of powder coatings based on polyacrylate resins. For this purpose, a wide range of monomers were selected—2-hydroxyethyl methacrylate (HEMA), methyl methacrylate (MMA), n-butyl acrylate (nBA), tert-butyl acrylate (tBA), dodecyl acrylate (DA), ethyl acrylate (EA) and benzyl acrylate (BAZ)—for the synthesis of the polyacrylate resin. The average molecular mass and molecular mass distribution of the synthesized resins were measured by gel permeation chromatography (GPC). The glass transition temperature (T_g) and viscosity of polyacrylate resins were determined by using differential scanning calorimetry (DSC) and a Brookfield viscometer. These parameters were necessary to obtain information about storage stability and behavior during the application of powder clear coatings. Additionally, DSC was also used to checked the course of the low-temperature curing reaction between the hydroxyl group contained in the polyacrylate resin and the blocked polyisocyanate group derived from a commercial agent such as Vestanat B 1358/100. The properties of the cured powder clear coatings were tested, such as: roughness, gloss, adhesion to the steel surface, hardness, cupping, scratch resistance, impact resistance and water contact angle. The best powder clear coating based on the polyacrylate resin L_HEMA/6MMA/0.5nBA/0.5DA was characterized as having good scratch resistance (550 g) and adhesion to the steel surface, a high water contact angle (93.53 deg.) and excellent cupping (13.38 mm). Moreover, its crosslinking density (CD) and its thermal stability was checked by using dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA). Full article

Covalent adaptable networks (CANs) represent a pioneering advance in polymer science, offering unprecedented versatility in materials design. Unlike conventional adhesives with irreversible bonds, CAN-based polyurethane adhesives have the unique ability to undergo chemical restructuring through reversible bonds. One of the strategies for incorporating these types of reactions in polyurethanes is by functionalisation with Diels–Alder (DA) adducts. By taking advantage of the reversible nature of the DA chemistry, the adhesive undergoes controlled crosslinking and decrosslinking processes, allowing for precise modulation of bond strength. This adaptability is critical in applications requiring reworkability or recyclability, as it allows for easy disassembly and reassembly of bonded components without compromising the integrity of the material. This study focuses on the sustainable synthesis and characterisation of a solvent-based polyurethane adhesive, obtained by functionalising a polyurethane prepolymer with DA diene and dienophiles. The characterisation of the adhesives was carried out using different experimental techniques: nuclear magnetic resonance spectroscopy (NMR), Brookfield viscosity, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and T-peel strength testing of leather/adhesive/rubber joints to determine the adhesive properties, both before and after the application of external stimuli. The conversion of both the DA and retro-Diels–Alder (r-DA) reactions was confirmed by ¹H-NMR. The adhesive properties were not altered by the functionalisation of the adhesive prepolymer, showing similar thermal resistance and good rheological and adhesive properties, even exceeding the most demanding technical requirements for upper-to-sole joints in footwear. After the application of an external thermal stimuli, the bonded materials separated without difficulty and without damage, thus facilitating their separation, recovery and recycling. Full article

The use of waste calcium sulfate whiskers in pavement construction is cost-effective and beneficial to the environment. In this paper, modified asphalt binders are prepared by adding calcium sulfate anhydrous whiskers (ACSW, 9 wt.%,11 wt.%, and 13 wt.% by weight of asphalt binder) and polyester fibers (4 wt.%,6 wt.%, and 8 wt.% by weight of asphalt binder). The viscosity-temperature, rheological, and low-temperature properties of the modified asphalt binder were evaluated using the Brookfield rotational viscosity test, the dynamic shear rheometer (DSR) test, the bending beam rheometer (BBR) test, and the force ductility test. The results demonstrated that the addition of the ACSW and polyester fiber could improve the anti-deformation and low-temperature properties of the asphalt binders, but reduce their viscosity-temperature properties to some extent. The modified asphalt binder with 11 wt.% ACSW and 8% polyester fiber showed the best anti-deformation property, while the 11 wt.% ACSW and 6 wt.% polyester fiber modified asphalt binder had a better low-temperature performance. The force ductility test was more suitable than the BBR test to characterize the low-temperature properties of the modified asphalt binders. The Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) tests were conducted to study the functional groups and micro-structure of the modified asphalt binders, and the results indicated that no new functional groups were generated and that the interaction between the ACSW, polyester fiber, and asphalt binder was a physical adsorption and interleaving process. Full article

Environmental approaches in the asphalt industry have focused on utilizing waste materials as modifiers. Lignin is a high-potential bitumen modifier due to its characteristics; however, the blending process with bitumen is critical. This study investigates the chemo-thermal characteristics of lignin-modified bitumen under two different blending protocols, including a mechanical and high-shear mixer to evaluate its performance as a modifier. According to the protocols, 5, 10, and 20% of Kraft lignin was added to a PG 58S−28 bitumen. The samples were subjected to analysis using Brookfield Rotational Viscosity (BRV), Dynamic Shear Rheometer (DSR), Fourier-Transform Infrared Spectroscopy (FTIR), Environmental Scanning Electron Microscopy (ESEM), Thermogravimetric Analysis (TGA), and Differential Scanning Calorimetry (DSC) tests. The BRV and DSR test results indicate a remarkable alteration in the rheological properties of lignin-modified bitumen under blending conditions. The FTIR analysis indicated that Kraft lignin did not produce new functional groups. The fibril structures of the bitumens are affected by Kraft lignin content and blending conditions due to ESEM. The Kraft lignin and blending conditions influence the thermal behavior of bitumen. The findings highlight Kraft lignin’s potential as a bitumen modifier, and the fact that its characteristics are influenced by the blending protocol and Kraft lignin content. Full article