Good High Temperature Performance Research Articles

A novel Ta-contained TiAl alloy with excellent high temperature performance designed for powder hot isostatic pressing

TiAl alloys offer strong potential for replacing conventional nickel-base alloys in structural applications at high temperatures, which requires good high temperature performance. This study analyzes the creep performance and thermal exposure characteristics for a powder hot isostatic pressing (P-HIP) Ta-contained TiAl alloy. The microstructure characteristics, creep performance, and thermal exposure properties of the nearly lamellar (NL) alloy with a size of about 145 μm were investigated. The alloy remains 0.72 % fracture strain at room temperature after exposure at 750 ℃ for 1000 h. The fitting results of creep curves show that the creep stress index n is 15.82 at 750 ℃, indicating the power law creep mechanism. By reducing the interfacial energy, Ta can facilitate the formation of metastable structures and achieve refinement. The enrichment of Ta element at the lamellar edge, both observed after thermal exposure and creep, inhibits the growth of lamellae and hinders the expansion of cavities due to its low diffusion rate, improving the thermal stabilities and creep performance. The P-HIP Ta-contained TiAl alloy shows exciting high temperature performance.

Tailoring microstructural stability and stress rupture properties of a solid-solution strengthened Fe-Ni-based superalloy via niobium addition

The influence of niobium (Nb) addition on the microstructural stability and 750 °C/135 MPa stress rupture properties of a solid-solution strengthened Fe-Ni-based superalloy designed for fourth-generation (Gen IV) nuclear reactors was systematically studied. The results showed that the stress rupture life first increased and then decreased with the increase of Nb content. The alloy with the addition of 0.5 wt% Nb exhibited the best stress rupture properties, with a stress rupture life of 164 h. Compared to Nb-free alloy, the stress rupture life has been increased by 382 %. The enhanced creep performance of this alloy was closely related to its excellent high-temperature microstructural stability, which can be explained as follows: homogeneous and optimal grain size distribution, elemental Nb provided good solid-solution strengthening effects, fine granular secondary carbides relieved stress concentration and strengthened grain boundaries (GBs), dynamic precipitation of nano-sized NbC carbides effectively pined dislocations. Dynamic recrystallization (DRX) behavior can be observed in all alloys. The mechanisms related to DRX behavior were discussed, and it was deemed that the smaller average grain size, higher blocky NbC volume fraction, and increased stacking-fault energy (SFE) may be responsible for the facilitated DRX in the alloy with higher Nb content, which greatly caused local softening and consequently, decreasing the creep resistance of the alloy. Important guidance for the further design and development of γ′-free Fe-Ni-based superalloys for Gen IV nuclear reactors with good high-temperature microstructural stability and creep performance could be summarized from the present study.

Deformation behavior of PST-TiAl bicrystals at 800 °C

PST (polysynthetic twinned) TiAl crystal exhibits excellent mechanical properties, and thus, it has been regarded as a critical candidate for turbine blades in the aero-engine industry. For the first time, the deformation behavior of PST-TiAl bicrystals with two different α2/γ lamellar orientations was studied in this work. Ti-46Al-6Nb bicrystals were cut from directionally solidified ingots, and three bicrystals of B1 (10°–14°), B2 (10°–19°), B3 (6°–75°) together with a single crystal of S1 (3°) were stretched at 800 °C. Then, the deformation behaviors, including fracture morphology, crack propagation, and deformation mechanism, were analyzed. Interestingly, these bicrystals show good high-temperature tensile performance, and their deformation behaviors seem to be very anisotropic. The findings indicate that the misorientation disparity in bicrystals primarily determines their deformation coordination capacity and corresponding mechanical performance. Subsequently, the difference in deformation orientation between the two lamellae significantly controls fracture behavior and deformation compatibility. High slip potential and abundant variant choices in γ phases are supposed to be beneficial for deformation capacity improvement. Meanwhile, the deformation potential of ordinary dislocation and superlattice dislocation slip systems in the α2 phase was also examined. Results show that the disparity in dislocation motion ability between γ variants gradually amplifies the advantages of the easy-mode phase in deformation through strain coordination, while mitigating the disadvantages associated with the difficult-mode phase. During further deformation, the relatively low bicrystal misorientation and small deformation capacity differences between the two lamellae determine high deformation coordination and improved performance. Overall, our work reveals that bicrystal deformation initiates at the relatively softer lamellae and proceeds to the harder lamellae, and its final comprehensive performance is determined by the deformation coordination capacity between the two lamellae.

Microstructure evolution and performance of TiMoCrWxTay refractory high-entropy alloy coatings prepared using laser cladding

Refractory high entropy alloy (RHEA) coatings containing W and Ta elements at the same time usually have excellent performance at high temperature, which are promising candidate materials for high temperature protective coating materials. In this work, the effects of W and Ta on the microstructure and performance evolution of TiMoCrWxTay RHEA coatings have been investigated. Experimentally, TiMoCrWxTay coatings are mainly composed of BCC phase, Laves phase and Ti-rich phase, with W and Ta atoms preferably dissolved in BCC phase. The W atoms promote the formation of dendrites and the growth of rod-like and equiaxed crystals and the Ta atoms promote the formation of cellular crystals and produce the effect of fine crystal strengthening. W and Ta atoms have significant influence on the tribological properties of TiMoCrWxTay coatings. The tribological properties of TiMoCrWxTay coatings at 800 °C are better than those at room temperature. TiMoCrWxTay RHEA coatings follow near-linear oxidation kinetics during the oxidation of 50 h at 800 °C.The oxidation resistance of the coatings first increases and then decreases with the increase of Ta content. Ta2O5, TiO2 and other oxides may have a shielding effect on the oxidation of W. In particular, The W0.3Ta0.5 shows the best tribological properties and oxidation resistance, and the mass gain of W0.3Ta0.5 is only 13.4 mg/cm2 after the oxidation test for 50 h. It indicates that TiMoCrWxTay coatings can obtain good high temperature performance by optimizing the content of W and Ta in RHEA coatings. This work can provide guidance for the research and application of TiMoCrWxTay RHEA coatings.

Castor oil-based polyurethane Vitrimer modified asphalts regulated by dual dynamic reversible reactions and crosslinking density: Preparation, basic assessment and self-healing behavior

Thermosetting polymers, commonly used to improve asphalt properties, bring excellent pavement performance, but also pose significant challenges to the healing and recyclability of their modified asphalts after long-term service. An effective approach involves introducing dynamic bonds into the crosslinking networks to synthesize Vitrimer-modified asphalts with self-healing response. Due to the splendid mechanical properties, high elasticity, flexibility and easily controllable cross-linked structure of polyurethane, a novel castor oil-based polyurethane Vitrimer modified asphalt with disulfide bonds and Diels-Alder reactions was developed. Based on the prepared castor oil-based polyurethane Vitrimer (C-PUV, composed of components A and B) and its modified asphalts (C-PUVAs), a comprehensive study was conducted on the crosslinking density, mechanical properties, thermal stability, viscosity, compatibility, rheological properties, and self-healing behavior. The results indicated that C-PUVAs (C-PUVA1/C-PUVA2/C-PUVA3/C-PUVA4) exhibited sufficient retention times for viscosity, uniform phase distribution, and good high-temperature performance. The damaged C-PUVAs achieved a mechanical strength recovery rate more than 75 % after the first cycle of self-healing at 80 ℃ and 0.3 MPa. Furthermore, the crosslinking density of C-PUV was regulated by the segment length of component B. As the crosslinking density increased, C-PUV and C-PUVAs obtained higher mechanical strength while sacrificing part of self-healing efficiency. The mechanism is that increased crosslinking density altered the gel point distributions of the reversible crosslinked networks, resulting in a longer relaxation time and higher activation energy. In conclusion, the above findings provided valuable insights for developing bio-based polyurethane Vitrimer modified asphalts, and endosing thermosetting polymer modified asphalts with self-healing and recyclable properties.

Synthesis and Characterization of a Temperature-Sensitive Microcapsule Gelling Agent for High-Temperature Acid Release.

Deep, high-temperature carbonate reservoirs, represented by the Chuanzhong-Gaomo Block and the Penglai Gas Field, have become important supports for increased storage and production in Sichuan Basin. However, acidization in high-temperature to ultrahigh-temperature reservoirs faces several technical challenges, such as fast acid-rock reaction rates, limited acid corrosion distances, and high risks of tubular corrosion. In this study, a novel high-temperature-resistant microencapsulated gelling agent GLE-3 was prepared using N-isopropylacrylamide (NIPAM) as the wall material, acrylamide (AM), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), and N-vinylcaprolactam (NVCL) as the core materials, and N,N'-methylenebis(acrylamide) (MBA) as the cross-linking agent through inverse emulsion polymerization. GLE-3 was structurally characterized using infrared spectroscopy, transmission electron microscopy, and particle size analysis, and its properties were evaluated. The results showed that GLE-3 exhibited uniform particle size distribution ranging from 10 to 100 μm. Under high-temperature conditions of 180 °C and a shear rate of 170 s-1, the viscosity of the gel acid solution remained above 27.8 mPa·s, with a viscosity retention rate of 63.76%. Compared to GLE-1 (uncapsulated), GLE-3 demonstrated improved thermal stability and shear stability after microencapsulation. After 60 min of shearing at 180 °C and shear rate of 170 s-1, the viscosity retention rate was 88.99%. Furthermore, under 180 °C conditions, GLE-3 exhibited good high-temperature slow-release performance compared to GLE-1, which unencapsulated with the same raw materials. By increasing the viscosity of the gel acid, delaying the acid-rock reaction rate, and providing high-temperature slow-release effects, the high-temperature resistance of the acid system was enhanced, ultimately achieving deep acidization in high-temperature reservoirs.

High-temperature oxidation behavior of TA15 aerospace titanium alloy at 500 °C and 800 °C

This study investigates the high-temperature oxidation behavior and performance of TA15 Ti alloy subjected to 500 and 800 °C service conditions. The oxidation process, microstructural evolution, mechanical property changes, and comprehensive performance were analyzed. At 500 °C, the alloy developed a distinctive blue-colored surface primarily composed of Ti6O, indicating a slow growth rate of the oxide layer. In contrast, the 800 °C condition led to severe oxidation with notable TiO2 and Al2O3 phases and extensive peeling of the oxidation layer. Microstructural analysis revealed that at 500 °C, there was minimal surface oxidation, and the microstructure showed a shallow heat-affected zone. At 800 °C, repeated oxidation and peeling cycles resulted in grain growth and a significant decrease in the β-phase proportion. Mechanical property assessments indicated an increase in micro Vickers hardness at both temperatures, with the 800 °C sample exhibiting higher values. However, tensile strength decreased significantly at 800 °C due to the severe oxidation layer peeling, reducing the effective thickness during tensile testing. In summary, TA15 demonstrated good high-temperature service performance at 500 °C, while at 800 °C, severe oxidation and peeling adversely affected the overall performance. This research provides insights into the differential high-temperature behavior of TA15, crucial for applications in elevated temperature environments.

Embrittlement Mechanisms of HR3C Pipe Steel at Room Temperature in Ultra-Supercritical Unit

HR3C steel is an austenitic high-temperature-resistant steel. Because of its good strength and high-temperature performance, it has been widely used in ultra-supercritical power plant boilers. With the increasingly frequent start-up and shutdown of thermal power units, leakages of HR3C steel pipes have occasionally occurred due to the embrittlement of HR3C pipe steel after a long service duration. In this study, the embrittlement mechanisms of HR3C pipe steel are investigated systematically. The mechanical properties of the pipe steel after running for 70,000 h in an ultra-supercritical unit were determined. As a comparison, the pipe steel supplied in the same batch was aged at 700 degrees Celsius for 500 h. The mechanical properties and the micro-precipitation of the aged counterparts were also determined for comparison. The results show that the embrittlement of HR3C pipe steel in service for 70,000 h is obvious. The average impact absorption is only 5.5 J, which is a decrease of 96.7%. It is found that embrittlement of HR3C steel also occurs after 500 h of aging at 700 °C, and the average value of impact absorption energy decreases by 70.4%. The comparison experiment between the in-service pipe steel and the aged pipe steel shows that in the rapid decline stage of the impact toughness of HR3C steel, the M23C6 carbide in the microstructure has a continuous chain distribution in the grain boundary. There were no other precipitated phases observed. The rapid precipitation and aggregation of M23C6 carbides leads to the initial embrittlement of HR3C steel at room temperature. The CRFe-type σ phase was found in the transmission electron microscope (TEM) image of the steel pipe after 70 thousand hours of use. The precipitation of the σ phase further induces the embrittlement of HR3C pipe steel after a long service duration.

Experimental Study on Enhanced Oil Recovery Effect of Profile Control System-Assisted Steam Flooding.

Steam flooding is an effective development method for heavy oil reservoirs, and the steam flooding assisted by the profile control system can plug the dominant channels and further improve the recovery factor. High-temperature-resistant foam as a profile control system is a hot research topic, and the key lies in the optimal design of the foam system. In this paper, lignin was modified by sulfonation to obtain a high-temperature-resistant modified lignin named CRF; the foaming agent CX-5 was confirmed to have good high-temperature foaming ability by reducing the surface tension; the formula of the profile control system (A compound system of CRF and CX-5, abbreviated as PCS) and the best application parameters were optimized by the foam resistance factor. Finally, the effect of PCS-assisted steam flooding in enhanced oil recovery was evaluated by single sand packing tube flooding, three parallel tube flooding, and large-scale sand packing model flooding experiments. The results show that CX-5 has a good high-temperature foaming performance; the foam volume can reach more than 180 mL at 300 °C, and the half-life is more than 300 s. The optimal PCS formulation is 0.3 wt% CRF as an oil displacement agent + 0.5 wt% CX-5 as a foaming agent. The optimal gas-liquid ratio range is 1:2 to 2:1, and the high pressure and permeability are more conducive to the generation and stability of the foam. Compared with steam flooding, PCS-assisted steam flooding can improve oil recovery by 9% and 7.9% at 200 °C and 270 °C, respectively. PCS can effectively improve the heterogeneity of the reservoir, and increase the oil recovery of the three-parallel tube flooding experiment by 28.7%. Finally, the displacement results of the sand-packing model with large dimensions show that PCS can also expand the swept volume of the homogeneous model, but the effect is 9.46% worse than that of the heterogeneous model.

Microstructure, Mechanical Property, and Wear Behavior of NiAl-Based High-Entropy Alloy

Based on the excellent comprehensive mechanical properties of high–entropy alloy (HEA), the NiAl-based HEA was designed to achieve excellent high-temperature strength, toughness, and wear resistance. In this work, vacuum arc melting technology was used to prepare (NiA1)78(CoCrFe)16.5Cu5.5 HEA, and its microstructure, phase composition, and mechanical properties were systematically studied. The results showed that (NiA1)78(CoCrFe)16.5Cu5.5 HEA was composed of FCC and BCC/B2, with a spinodal decomposition structure in the matrix, and nano-precipitation in the interdendritic, exhibiting a good high-temperature performance. At 600 °C, the compressive fracture strength is 842.5 MPa and the fracture strain is 24.5%. When the temperature reaches 800 °C, even if the strain reaches 50%, the alloy will not fracture, and the stress–strain curve shows typical work hardening and softening characteristics. The wear coefficient of the alloy first increases and then decreases with the increase in temperature in the range of room temperature to 400 °C. However, the specific wear rate shows the opposite trend. At 100 °C, the wear rate reaches the lowest of 7.05 × 10−5 mm3/Nm, and the wear mechanism is mainly abrasive wear.

Fabrication, high-temperature mechanical behavior, and oxidation resistance of high entropy alloys: A review

High entropy alloys (HEAs), as a new type of alloy, have attracted increasing attention since it was developed in 2004, showing high engineering potential in various fields. This paper provides a comprehensive review of the recent progress in their fabrication, high-temperature mechanical behavior, and oxidation resistance. It begins with an introduction of the effects of intrinsic characteristics of HEAs on their physical properties, focusing on the four typical effects including the high-entropy effect, the sluggish diffusion effect, the severe lattice effect, and the cocktail effect. Fabrication methods of HEA feeding powders, HEA blocks, and HEA coatings are then analyzed from the methodologies to mechanical properties. Afterward, the recent progress of FeCoCrNiAlTi HEAs and refractory HEAs which both demonstrated excellent mechanical properties at high temperatures is discussed with the underlying mechanisms, such as the chemical composition effect, the phase structure effect, and the strengthening effect. Recent antioxidant strategies including the formation of Al oxides, Cr oxides, and Si oxides in HEAs are highlighted. This review is concluded with prospects on challenges and future directions in the critical fields, such as their fundamental applications and design strategies of advanced HEAs with good high-temperature performance.

Study of the Bonding Performance and Application of an Epoxy Resin Pavement Sealant

An epoxy resin pavement sealant (ERPS) was prepared to solve the interface bonding failure problem of traditional road sealants. The fluidity, bonding performance, and low temperature performance of sealants repaired struture were studied based on surface energy theory, fluidity tests, tensile tests, beam bending tests, and oblique shear tests. The results show that ERPS has good excellent fluidity and can meet the construction time. Under the most unfavorable condition of water, mineral powder, and low temperature, the tensile bond strength, flexural bond strength, and oblique shear bond strength of ERPS repair specimens were 1.84, 7.21, and 8.02 MPa, respectively, and the strength at each temperature was better than styrene-butadiene-styrene (SBS)-modified asphalt, silicone sealant, and polyurethane sealant. Under the most unfavorable conditions, the ERPS-repaired cracks recovered 68.1% of the tensile strength, 67.8% of the flexural strength, and 70.5% of the oblique shear strength of the undamaged specimens. The ERPS-repaired pavement crack wall structure has excellent low-temperature bonding performance and good high-temperature shear performance, which shows that ERPS can effectively solve the problem of adhesive failure sealants at low temperatures.

Optimized Performance Design of Low Freezing Point Asphalt Mixture for Northern Mountainous Areas

Due to the lack of research on the applicability and optimization design of low freezing point asphalt mixtures in specific environments, especially for the harsh environments of low freezing point asphalt mixtures in mountainous areas during cold winter and high humidity in other seasons, there is a significant engineering demand. This paper carries out a study on the performance optimization design of low freezing point asphalt mixtures in northern mountainous areas. Through comparative analysis of low freezing point asphalt mixture technologies and analysis of the road performance of low freezing point asphalt mixtures, combined with the climate and driving characteristics of northern mountainous areas, the low freezing point asphalt mixture suitable for northern mountainous areas is selected. The research shows that the hygroscopicity of M low freezing point filler is significantly stronger than that of Z low freezing point filler, and since the humidity in northern mountainous areas is relatively high, selecting low freezing point fillers with lower hygroscopicity to prepare low freezing point asphalt mixtures can avoid safety accidents caused by excessively wet road surfaces. SBS modified asphalt and waste tire rubber powder modified asphalt can both produce low freezing point asphalt mixtures that meet the requirements of standard road performance, and both have good high and low temperature performance. When conditions permit, waste tire rubber powder modified asphalt low freezing point asphalt mixture is recommended as the first choice.

Stereocomplex crystals induced outstanding energy storage performance with PLLA/PDLA blend film

Poly(lactic acid)-based (PLA) films with biodegradability and ease of processing are promising dielectrics for application in electrostatic capacitors. Nevertheless, the relative low energy storage capability of the PLA film greatly hampers the development of its further application. Herein, a biodegradable polymer of stereocomplex crystals of poly(lactic acid) is prepared utilizing a solution blending method of the co-blended poly-L-lactic acid (PLLA) and poly-D-lactic acid (PDLA) in a 1:1 ratio. The stereocomplex crystals could prominently improve insulation and mechanical properties of PLLA/PDLA blend films, thus achieving an outstanding energy density (Ud ∼ 13.7 J/cm3) accompanied with high efficiency (η ∼ 92.8%) at a breakdown electric field of 750 MV/m. Additionally, the PLLA/PDLA blend film also exhibit good high-temperature performance and reliability. This work provides a reasonable tailoring strategy for biodegradable polymer dielectrics and demonstrates a great potential of biodegradable polymers for practical applications in environmentally friendly power electronics and electrical systems.

High Temperature Tribological Behavior of Electroless Plating Ni-P-Si3N4-WS2 Composite Coatings

Electroless nickel composite coatings have the potential for high-temperature tribological applications, and a combination of high wear resistance and low friction factor is one of the desirable solutions but still a tricky problem. The addition of self-lubricating WS2 and hard Si3N4 nanoparticles to the Ni-P coatings is expected to obtain good high-temperature tribological performance. In this work, Ni-P-Si3N4-WS2 composite coatings with various contents of WS2 nanoparticles were prepared using electroless plating and subsequently annealed at 400 °C in an inert atmosphere. The tribological properties of the coatings were evaluated using a ball-on-disc wear instrument at operating temperatures from 25 to 600 °C. The microstructure, chemical composition, and surface morphology of the coatings were characterized by X-ray diffractometry (XRD), energy disperse spectroscopy (EDS), and scanning electron microscopy (SEM). Upon increasing the WS2 dosage in the bath, the WS2 content in the coating increased and the micro-hardness of the as-plated coating increased from 539 to 717 HV. After heat treatment, the coating underwent a crystallization process, and the hardness increased from 878 to 1094 HV. The main wear mechanism of the coating changed from adhesive wear in the as-plated state to abrasive wear in the annealed state. The annealed Ni-P-Si3N4-WS2 coating with a WS2 dosage of 2.5 g/L in the bath exhibited excellent mechanical properties, with a hardness of 10.9 GPa, a friction coefficient of ~0.51, and a wear rate of 8.4 × 10−15 m3N−1⋅m−1 at room temperature, and maintained optimal performance at high temperatures. At operating temperatures of 200, 400, and 600 °C, the form of wear was adhesive wear for coatings with a WS2 dosage <1.5 g/L and abrasive wear for coatings with a WS2 dosage ≥1.5 g/L. The synergism of WS2 and Si3N4 particles refined the grains of the Ni-P matrix in as-plated coatings and obviously reduced the friction coefficient of friction pairs in annealed coatings at all operating temperatures.

The Effect of Temperature and Asphaltene Content on the Lubricating Properties of Fuel Oils

During coal-based power generation, fuel oil is used to assist with ignition of pulverised coal. Fuel oil passes through several pieces of equipment on its way to the burner section of the boiler. In this article the focus is on the lubricity behaviour of three representative fuel oil types and on the potential blocking of filters and nozzles caused by the presence of unwanted components in these fuel oils. The high frequency reciprocating rig (HFRR) (ISO 12156-1) was used to determine the lubricity of these fuel oils at different temperatures. Results indicate that the presence of asphaltenes (components of heavy fuel oils with complex aromatic structures) changes the viscosities of fuel oils, which, in turn affect their lubricity behaviour. Medium wax-blend fuel oil (MFO) containing high molecular weight paraffins (wax), low concentrations of asphaltenes and solid particles caused less friction and wear (with coefficient of friction (COF) values below 0.1) and good high temperature performance. Crude-derived heavy fuel oil (HFO), containing high concentrations of asphaltenes and solid particles caused very high coefficients of friction (COF peaks above 0.3) and severe abrasive wear at high temperatures. Although the third fuel oil tested was a light cycle oil (LFO) and did not contain any asphaltenes, results indicated a sensitivity to oxidation, increasing with temperature, which can have an adverse effect on in situ performance.

Study on high temperature performance of coal based modified asphalt mixture

SHA, as a solid waste from direct coal liquefaction, has a certain application prospect. Based on the original concept and process of coal based clean asphalt preparation, this paper studies the performance of SHA coal based modified asphalt mixture, and draws the following conclusions: (1) SHA modified asphalt has the characteristics of hard asphalt (2) Compared with traditional SBS modified asphalt mixture, SHA modified asphalt mixture has good high temperature performance (3) SHA modified asphalt mixture has small rutting rolling depth, which can improve the rutting resistance of asphalt pavement.

Gradation design and performance evaluation of modified asphalt mixture for bridge asphalt plug joint design

Although the Asphalt Plug Joint (APJ) has been developed for half a century to overcome the maintenance issues in traditional bridges, its shortcomings, such as short service life and poor deformation capacity, have not been overcome. There are currently no adequate specifications in place to guide the material design and performance evaluation of APJs. Therefore, this study proposes a suitable design method for asphalt mixtures based on the mechanical characteristics and performance requirements of APJ. According to the proposed mixture type, the influence of gradation type on the bonding strength, shear strength, and tensile strength of the APJ mixture is explored mainly based on direct shear test, direct tensile test, and meso-structure analysis. In addition, the effect of fiber type on improving the performance of mixture and the influence of temperature on the performance of the mixture are discussed. The test results show that it is recommended to use a skeleton-filled asphalt mixture with a lower void ratio, more fine aggregates, more mineral powder, and more asphalt in the APJ. Similarly, modified asphalt with good high and low temperature performance should be selected, and an appropriate amount of reinforcing fibers, such as polyacrylonitrile fiber and basalt fiber, should be added to the asphalt mixture.

Effect of Oils on SBS Modified Asphalt: Rheological Characteristics and Oxidation Aging

This study focuses on the effect of oils on rheology and oxidation aging of Styrene-Butadiene-Styrene modified asphalt (SBSMA) in the long term, after reducing one low-temperature Performance Grade (PG) of SBSMA by incorporating oils. Two oils, including corn-based bio-oil and re-refined engine oil bottom (REOB), were selected to enhance the low-temperature performance of SBSMA. All samples were subjected to Rolling Thin Film Oven (RTFO) aging and 20-h as well as 40-h Pressure Aging Vessel (PAV20 and PAV40) aging, prior to multiple stress creep recovery (MSCR), frequency sweep and Flourier transform infrared spectroscopy (FTIR) scanning. A good high-temperature performance of oil/SBS modified asphalt blends was reflected in MSCR and PG results, meanwhile non-recoverable creep compliance (Jnr) and recovery (R) were found to share a highly correlated relationship during aging progress. In addition, Glover–Rowe (G–R) parameter and phase angle master curves suggest that the improvement of cracking property mainly came from the softening effect of oils. Adding oils into SBSMA was observed to increase oxidation kinetics, but the blends with oils still exhibited better anti-oxidation aging than the base binder, mainly due to the SBS addition. Bio-oil exhibited an effect of relieving age hardening susceptibility of SBSMA.

Performance evaluation of Xinjiang Tianzhize 90A road petroleum asphalt and mixture

The objective of this paper is to introduce a new kind of asphalt binder of Xinjiang Tianzhize 90A road petroleum asphalt, and the basic performance of it and the pavement performance and mechanical property of its mixture were investigated by a series of laboratory tests and compared with Karamay 90# asphalt. Results show that the Xinjiang Tianzhize 90A road petroleum asphalt and mixture have good basic and pavement performance, such as good high temperature performance and waterproof performance. Besides, the Xinjiang Tianzhize 90A road petroleum asphalt mixture has good mechanical properties. However, the low temperature performance of Xinjiang Tianzhize 90A road petroleum asphalt mixture is not outstanding. The Karamay 90# asphalt mixture has better performance at low temperature and high load frequency. The study of this paper laid a foundation for the investigation and field engineer application of Xinjiang Tianzhize 90A road petroleum asphalt.