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As a kind of solid waste, using Prestressed High-Strength Concrete Pile Waste Concrete (PPWC) as the replacement for limestone filler in asphalt concrete can not only reduce the accumulation of PPWC and increase its utilization but also avoid the increased road construction costs and environmental degradation associated with limestone mining. This study aims to investigate the effect of using PPWC filler to replace limestone filler on the road performance of asphalt concrete. Firstly, PPWC was ground into filler particles with a diameter less than 0.075 mm. The particle characteristics such as surface morphology, particle size distribution and chemical composition of PPWC filler and limestone filler were compared. Then, PPWC filler was used to replace limestone filler with different volume fractions to prepare asphalt concrete, and the water damage resistance, high-temperature rutting resistance, low-temperature crack resistance, fatigue resistance and adhesion performance of asphalt concrete were tested. The results showed that PPWC filler has a smaller particle size and rougher surface than limestone filler, and it contains Ca(OH)2 produced by hydration. The addition of PPWC filler can effectively improve the mechanical properties of asphalt concrete without reducing its water damage resistance. PPWC filler can improve the high-temperature rutting resistance and low-temperature crack resistance of asphalt concrete, but reduce its low-temperature fatigue resistance. The low content of PPWC filler will enhance the adhesion between asphalt mortar and aggregate. However, when the content of PPWC filler exceeds 50%, Ca (OH)2 in PPWC will reduce the adhesion between acid asphalt mortar and alkaline basalt aggregate. Therefore, the use of PPWC as filler in asphalt mixtures provides a reliable solution for the sustainable development of road materials.

The large amount of recycled asphalt pavement mixture (RAP) generated during renovations has a negative impact on the environment. In recent years, how to rationally recycle and reuse RAP has become a hot research direction in the field of highway construction. However, the recycled asphalt binder has some problems such as instability, easy aging and decreased adhesion. In this paper, carbon nanotubes and waste engine oil were used to modify recycled asphalt binder. Through a high-temperature rutting test, low-temperature bending test and Marshall stability test, the properties of an asphalt mixture with 40% RAP modified by carbon nanotubes and waste engine oil, an asphalt mixture with 40% RAP and an asphalt mixture without RAP were compared and analyzed. The tests showed that 1.5 wt% carbon nanotubes could improve the performance of the old asphalt binder most significantly. After adding 1.5 wt% carbon nanotubes, the high-temperature rutting resistance of the asphalt mixture was increased by 24.3%, and the bending stiffness modulus and the best crack resistance at low temperature increased significantly. In addition, after adding 1.5 wt% carbon nanotubes, the Marshall stability of the waste-engine-oil-modified RAP could be restored to the level of the new asphalt mixture. In summary, carbon nanotubes can improve the high-temperature stability, low-temperature crack resistance and Marshall stability of waste-engine-oil-modified RAP. [ABSTRACT FROM AUTHOR]

Snow and ice accumulation on asphalt pavement can increase the risk of traffic issues. The traditional method of removing snow and ice manually or mechanically from the road surface is time-consuming and labor-intensive. Another common method of spraying salt pollutes the surrounding environment. To overcome these issues, the objective of this study is to study a polyurethane superhydrophobic coating on asphalt pavement and characterize its anti-icing and road properties. A polyurethane superhydrophobic coating (PSC) using polyurethane and carbon nanotube particles (CNTPs) was developed in the lab. The contact angle and roll angle tests, surface roughness test, water droplet icing test, differential scanning calorimetry (DSC) test, ice adhesion test, pavement skid resistance test, water permeability test, and load wheel rolling test were conducted. The results show that the static contact angle and the rolling angle of the water droplet on the PSC surface are 161.176° and 6.6°, which satisfy the requirements to be superhydrophobic. The icing time of the water droplet on the asphalt mixture coated with PSC (AMC) is twice that of the surface of the ordinary asphalt mixture (OAM). In the differential scanning calorimetry test, the PSC released heat slower than polyurethane and asphalt binder during the cooling process. The ice adhesion strength of AMC is 82.78% smaller than that of the OAM. This means the PSC has great anti-icing and deicing properties. In addition, the pendulum value on the AMC surface is 45.7, satisfying the pavement skid resistance requirement. The results of the water seepage test show that the AMC is impermeable to water, thus reducing the risk of water damage to the pavement. Finally, the contact angle of the AMC after the indoor load wheel rolling is still greater than 150°, which proves that the PSC has good wear resistance. In summary, the PSC has good anti-icing properties and road performance. [ABSTRACT FROM AUTHOR]

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Copyright of Transportation Science & Technolgy is the property of Transportation Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transportation Science & Technolgy is the property of Transportation Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Blending behavior is the main factor influencing hot recycled asphalt mixtures' actual and design performance. The following steps were taken to investigate the above issues. Firstly, the component changes of asphalt mixtures were studied by thin-layer chromatography, with flame ionization detection to obtain the mechanism of asphalt aging and recycling. Secondly, according to the difference in the recycled asphalt components, the hot recycled asphalt mixtures were optimized based on the Marshall design method. Lastly, the hot recycled asphalt mixtures for the three mixing processes were prepared using the optimized design method described above. Laboratory tests were conducted to evaluate the correlation between the degree of blending (DoB) and the high-temperature stability, low-temperature crack resistance, water stability, and fatigue performance. The test results indicate that reducing light components (saturates and aromatics) and increasing heavy components (asphaltenes and resins) are the main reasons for asphalt aging, and asphalt recycling is an inverse process. Additionally, the performance of hot recycled asphalt mixtures is improved with an increase in DoB. Specifically, the DoB is only 50% to 60% under a normal mixing process, but by adjusting parameters the DoB will increase to 80% to 90%. [ABSTRACT FROM AUTHOR]

The number of residents in Ambon City every year has increased, therefore the number of increases in vehicle volume is directly proportional to the number of population growth, and in line with the increasing problem of traffic congestion. One of the traffic jams that occur in Ambon City is on the Kakialy road, which is caused by side obstacles due to unattended vehicle parking on the road, especially during rush hour or peak hours (during school and after school or commuting and returning from work). The existence of community facilities such as shops, fast food areas, hotels, and residential areas is also one of the triggers for road body parking which causes congestion on the Kakialy road section. Therefore, this study was conducted to find out how the performance of the Kakialy road section during peak and normal hours. The method used is a descriptive survey that uses data collection techniques in the form of observation and documentation studies for the calculation of capacity and speed on urban roads using the Indonesian Road Capacity Manual (MKJI) method. The results of data analysis show that the capacity of peak hours at 12.00-13.00 WIT) is 18,721 junior high school/hour and normal hours at 16.00-17.00 WIT is 15,037.8 junior high school/hour, with a vehicle density value (DS) at peak hours of 0.59. The average side resistance data in peak hours has a weighted frequency of 366.6 SMP/hour so it belongs to the medium side resistance class (M), and the average side resistance in normal hours has a weighted frequency of 148.7 SMP/hour, including the low side resistance class (L). So that after going through the calculation analysis process, it is concluded that the vehicle density value (DS) at peak hours (12.00 - 13.00 WIT) is 0.59 and is categorized in Level Of Service (LOS) C which means medium performance. While the vehicle density value (DS) during normal hours (16.00 - 17.00 WIT) is 0.45 and is categorized in Level Of Service (LOS) B which means good performance. [ABSTRACT FROM AUTHOR]

To determine the road performance and optimum dosing of solid-waste-based gelling agents in road subgrade, we conducted unconfined compressive strength testing for clay, sandy soil, weathered sand, and crushed stone mixed with different proportions of solid-waste gelling agents and compared the results with the road performance of cement-stabilized crushed stone materials. The results show that the optimum admixture of cementitious materials for clay and clay is 8–10%. The optimum admixture of cementitious materials for weathered sand is 5–7%. The optimum admixture of cementitious materials for stabilized gravel is 5.5%. The late strength growth of stabilized gravel with solid-waste-based cementitious agents is significantly better than that of cement-stabilized gravel. [ABSTRACT FROM AUTHOR]

High-modulus asphalt mixes are effective means to solve rutting problems, but they perform poorly at low temperatures. This study aims to enhance the modulus and low-temperature properties of mixes. Firstly, composite-modified asphalts and mixes were prepared by incorporating rubber powder and rock asphalt. Secondly, their mechanical and viscoelastic properties were investigated to determine the appropriate mass ratios of rubber powder and rock asphalt in asphalt to be 20% and 6%, respectively. The results show that both rock asphalt and rubber powder can enhance the softening point and viscosity of basic asphalt while reducing penetration. Furthermore, their combination significantly improves the high-temperature performance of the material. It is noteworthy that the rubber powder also improves the weakening of rock asphalt for mixtures at low temperatures. Finally, this study employs dynamic and static modulus tests, rutting tests, and beam bending tests to clarify the road properties of composite-modified asphalt mixes. The results indicate that mixes have high-modulus and water damage resistance while considering acceptable low-temperature performance. This paper not only enhances the adaptability of high-modulus asphalt in different environments but also expands its application range. [ABSTRACT FROM AUTHOR]

In this paper, mixtures with different proportions of lime, phosphogypsum, and red clay were prepared, and the road properties and micromechanisms of lime–phosphogypsum-stabilized red clay were investigated by unconfined compressive strength test, water stability test, swelling test, shrinkage test, XRD quantitative analysis, and scanning electron microscope analysis. The results showed that the unconfined compressive strength of the mix increased and then decreased with the increase of phosphogypsum content. With the increase of age, the growth was faster in the first 14 days and basically stabilized in the last 14 days. The mixture has poor water stability, large absolute swelling rate, and low linear shrinkage. The reason for the increase of strength is that the reaction of lime, phosphogypsum, and red clay produces ettringite, and the cementing substance gels form a three-dimensional mesh skeleton structure; the excess of ettringite will cause the skeleton to expand and break, and the strength decreases. [ABSTRACT FROM AUTHOR]

Considering the characteristics of steel slag, the effective relative density of steel slag was measured by the impregnation method. By the volume substitution method, the asphalt mixtures with different steel slag content were prepared for replacing the coarse aggregates. According to the technical requirements of the ultra-thin friction course, the road performance and the function characteristics of the steel slag asphalt mixture were evaluated. The test results show that with the increasing of steel slag content, the performance indexes of dynamic stability, maximum tensile strain and tensile strength ratio of asphalt mixture are increased with latter decreasing. When the steel slag content is 50%, the comprehensive performance of asphalt mixture is the best. With the increasing of the placement time of test specimens, the high temperature performance index of the steel slag asphalt mixture is increased slightly, while the low temperature crack resistance index and water stability index are decreased. The skid resistance and abrasion resistance of asphalt mixture are significantly improved with the addition of steel slag. The impermeability of the mixture is reduced, while the water seepage coefficient values of several steel slag asphalt mixtures can still meet the requirements of the standard test methods of bitumen and bituminous mixtures for highway engineering (JTG E20—2011). [ABSTRACT FROM AUTHOR]

The influence of basalt fiber content, nano-TiO2/ZnO content and oil/stone ratio on pavement performance of asphalt mixture was investigated, the composite modified asphalt mixes were prepared according to the optimal solution・ Road performance verification by rutting test, low temperature bending test, water immersion Marshall test, freeze-thaw splitting test and four-point bending fatigue test. The results showed that the optimal ratio of composite modified asphalt mixture was 3. 99% nano-TiO2/ZnO doping, 6・ 16% basalt fiber doping, and 5. 44% oil to stone ratio. The road performance of the composite modified asphalt mixture was significantly improved under this scheme, with the most significant improvement in water stability and high-temperature performance compared to the base asphalt and the modified asphalt mixture using only basalt fibers・ Under different strain conditions, the fatigue life of the composite modified asphalt mix was the maximum among the three mixes, but its low temperature performance less enhanced compared to that of the basalt fiber modified asphalt mix only. [ABSTRACT FROM AUTHOR]

In order to explore the effects of various test factors and curing agents on the mechanical and road properties of solidified saline soil, industrial and construction wastes such as cement kiln dust and recycled fine powder of waste concrete were used as solidification schemes. With the initial moisture content, curing age and curing agent content as the test factors, the mechanical properties of solidified saline soil were studied by unconfined compression test. The dry-wet and freeze-thaw durability test and bearing ratio test were carried out to evaluate the road performance of solidified saline soil. Scanning electron microscope test was used to analyze the microstructure of solidified saline soil and reveal its curing mechanism. The results show that initial moisture content, curing age, curing agent content and curing agent type are the main factors affecting the mechanical properties and road performance of solidified saline soil. After 28 days of curing, the mechanical properties and road performance of saline soil cured with 30% recycled fine powder of waste concrete are the best, the compressive strength reaches 3 227. 40 kPa, and the residual strength after dry-wet and freeze-thaw cycles reaches 2 924. 60 kPa and 2 243. 49 kPa, respectively. From the microscopic analysis, it can be seen that the soil structure of saline soil solidified by recycled micro-powder of waste concrete becomes dense and stable. It can be seen that the saline soil solidified with 30% recycled fine powder of waste concrete with an initial moisture content of 9. 9% has certain engineering significance and economic value to be used in the construction of highway roadbed and pavement base in saline land area. [ABSTRACT FROM AUTHOR]

Epoxy asphalt mixture with the epoxy system (EPS) and basalt has excellent road performance, but due to its high price, epoxy asphalt mixture is limited in its applications in conventional pavement. In addition, the basalt aggregate commonly used in epoxy asphalt mixture has shortages of high cost and insufficient reserves. This paper tries to reduce the EPS content and select suitable aggregates to prepare epoxy asphalt mixture with good road performance for conventional pavement. Basalt epoxy asphalt mixture (BEAM) and limestone epoxy asphalt mixture (LEAM) were designed based on the Bailey method. The road performance of BEAM and LEAM was evaluated by the Marshall test, rutting test, low-temperature bending test, water stability test, and fatigue test. Meanwhile, the mechanism of the EPS on the road performance of the mixture was revealed by the laser scanning confocal microscopy test. The results showed that the high-temperature deformation resistance, water damage resistance, and fatigue resistance of BEAM and LEAM were improved with the increase of EPS content, but the low-temperature crack resistance of the two mixtures was slightly decreased. Especially when the EPS content was 35 wt%, the performance change of BEAM and LEAM was more significant, which was caused by the phase transition in epoxy asphalt (EA). Therefore, 35 wt% EPS was recommended in EA. In addition, compared with BEAM, LEAM had better low-temperature crack resistance, less favorable high-temperature deformation, and fatigue resistance. The addition of EPS availably decreased the difference in road performance between LEAM and BEAM. Meanwhile, LEAM showed obvious cost advantages over BEAM. The research results of this paper had positive significance for expanding the engineering application of epoxy asphalt mixtures. [ABSTRACT FROM AUTHOR]

Copyright of New Building Materials / Xinxing Jianzhu Cailiao is the property of New Building Materials Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The current focus of research attention on reclaimed asphalt pavement (RAP) utilization is expanding the applications of RAP. This study aims to analyze the road performance of recycled permeable asphalt mixtures (RPAMs), which represents a novel direction for utilizing RAP. Firstly, the Marshall design method was used to carry out the material composition design of the RPAM with varying RAP contents (10%, 20%, and 30%). Subsequently, the performance of the RPAM with different RAP contents (10%, 20%, and 30%) and preheating temperatures (120 °C, 130 °C, 140 °C, 150 °C, and 160 °C) was tested with a permeable asphalt mixture containing 12% high-viscosity asphalt as the control group. The mixture's performance included high-temperature stability, low-temperature crack resistance, water stability, anti-raveling performance, and dynamic mechanical properties. The results indicate that the higher the RAP content, the better the high-temperature performance of the RPAM, while the low-temperature performance, water stability, and anti-raveling performance deteriorate. At 30% RAP content, its pavement performance is comparable to that of the control group mixture. However, increasing RAP preheating temperature can improve low-temperature and water stability but may reduce high-temperature performance. The optimal RAP preheating temperature for pavement performance is between 140 and 150 °C. The dynamic modulus test showed that the higher the RAP content, the greater the dynamic modulus of the RPAM, leading to better high-temperature stability but reduced low-temperature crack resistance. The influence of RAP preheating temperature is the opposite. These test results demonstrate the feasibility of utilizing RAP for paving permeable asphalt pavement under controlled RAP content and preheating temperature conditions. [ABSTRACT FROM AUTHOR]

This study aimed to assess the viability of utilizing lime–fly ash (LF) and red mud (RM) in the modification of silty soil (LF-RMS) for subgrade filling. The primary objective of this research was to analyze the mechanical characteristics and examine the curing mechanisms associated with said modified materials. Different curing times were utilized in the analysis of mechanical properties (e.g., via unconfined compression testing), microstructure (via scanning electron microscopy, X-ray diffraction, and thermogravimetric-differential thermal analysis), and environmental indices (via assessment of corrosivity, heavy metal concentration, and radioactivity) with various dosages of red mud (DRM) and Lime–fly ash (DLF). Analyses of the curing mechanisms, failure modes, microstructures, and degrees of environmental impact associated with LF-RMS were also undertaken. The tests indicated that the unconfined compressive strength (UCS) exhibited an initial increase followed by a decrease as the DRM and DLF levels increased. Additionally, the strength of LF-RMS increased with an increase in curing time. It is worth noting that the specimen composed of 20% LF and 23% RM (D20%LF+23%RM) demonstrated a maximum UCS value of 4.72 MPa after 90 days of curing, which indicates that it has the strongest ability to resist deformation. The strength of the specimen cured for 90 days was 1.4 times higher than that of the specimen cured for 7 days (1.97 MPa). Furthermore, the toxic concentration and radionuclide index of LF-RMS were significantly reduced compared to those of pure RM. The overall concentration of heavy metals in the D20%LF+23%RM specimen decreased by more than 60% after curing for 28 days. The internal irradiation index and the external irradiation index decreased by 1.63 and 1.69, respectively. The hydration products in LF-RMS play a key role in the solidification of heavy metals, and the alkaline environment provided by RM also contributes to the precipitation and replacement of heavy metals. In this study, red mud, fly ash and lime were used to modify silty soil. The central tenets of sustainable development may be achieved through the reuse of RM as a road filler.

To explore and deal with the difficulty in curing cement-stabilized bases in desert environments, curing agents were prepared to enhance the curing effect on the base in this research. The composite curing agent was prepared through orthogonal experiments and the durability of the curing agent coating were studied by simulating a desert environment. Subsequently, the curing effect on the performance of bases was analyzed. Finally, the hydration degree of cement was studied via scanning electron microscope (SEM), thermogravimetric analysis (TG), and X-ray diffraction analysis (XRD), and the curing mechanism of the curing agent was explored. The results show that the composite (paraffin emulsion is the main component of the film, vinyl acetate-ethylene copolymer dosage is 20%, ethanol ester-12 dosage is 10%, and sodium silicate dosage is 18%) could effectively improve the water-retention performance (water-loss ratio: 2.36%) and mechanical properties of the specimen (7 d compressive strength: 7.48 MPa; 7 d indirect tensile strength: 0.70 MPa). The dry shrinkage coefficient of the specimen with composite curing agent was reduced by 116.26% at 28 days. The compressive strength of dry and wet freeze could reach 7.48 MPa and 6.88 MPa, respectively. The durability of the curing agent-coated base met the requirements of pavement performance in desert areas. The results of XRD, TG, and SEM indicated that the curing agent promoted hydration. In addition, the number of C-S-H gel and AFt crystals significantly increased. The curing difficulty of road bases in desert areas could be reduced effectively through the application presented in this study, which contributes to the conservation of natural and human resources.

Purpose: Gajah Mada Road, Batam Taman Kota area is a primary collector road 1 that has a U-Turn and dense current if passed by motorists on weekdays in the afternoon. This study aims to analyze road performance due to the closure and opening of U-Turn access. Design/methodology/approach: The research method used systematic observation is carried out on Mondays and Fridays (weekdays when the U-Turn is closed and opens) at 17.15 - 18.00 WIB in MKJI 1997. Findings: The volume of vehicles and the average speed of vehicles passing when the U-Turn is closed is higher compared to the U-Turn is opened. Meanwhile, the level of road service (LoS) is classified as good because of the stable current and normal volume even though the vehicle speed is limited and affected by traffic. Research limitations/implications: The U-Turn closure policy is believed to be a solution to reducing vehicle congestion. Practical implications: Vehicle buildup factors due to U-Turn access are the main factors hampering road performance. Originality/value: This paper is an original work. Paper type: Research papers.

Semi-flexible pavement material (SFPM) combines the advantages and avoids the disadvantages of asphalt concrete flexible pavement and cement concrete rigid pavement. However, due to the problem of interfacial strength of composite materials, SFPM is prone to cracking diseases, which limits the further application of SFPM. Hence, it is necessary to optimize the composition design of SFPM and improve its road performance. In this study, the effects of cationic emulsified asphalt, silane coupling agent and styrene–butadiene latex on the improvement of SFPM performance were compared and analyzed. The influence of modifier dosage and preparation parameters on the road performance of SFPM was investigated by an orthogonal experimental design combined with principal component analysis (PCA). The best modifier and the corresponding preparation process were selected. On this basis, the mechanism of SFPM road performance improvement was further analyzed by scanning electron microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) spectral analysis. The results show that adding modifiers can significantly enhance the road performance of SFPM. Compared to silane coupling agents and styrene–butadiene latex, cationic emulsified asphalt changes the internal structure of cement-based grouting material and increases the interfacial modulus of SFPM by 242%, allowing cationic emulsified asphalt-SFPM (C-SFPM) to exhibit better road performance. According to the results of the principal component analysis, C-SFPM has the best overall performance compared to other SFPMs. Therefore, cationic emulsified asphalt is the most effective modifier for SFPM. The optimal amount of cationic emulsified asphalt is 5%, and the best preparation process involves vibration at a frequency of 60 Hz for 10 min and 28 days of maintenance. The study provides a method and basis for improving the road performance of SFPM and a reference for designing the material composition of SFPM mixes. [ABSTRACT FROM AUTHOR]

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In order to analyze the effect of waterborne epoxy resin on the pavement performance of cold recycled emulsified asphalt mixture, the effect of waterborne epoxy resin was studied based on the orthogonal experimental design method and the pavement performance test of asphalt mixture. The results show that the microstructure of cold recycled waterborne epoxy resin emulsified asphalt presents a rough and porous spatial grid structure. Waterborne epoxy resin can effectively improve the strength, vertical deformation resistance and water stability of cold recycled emulsified asphalt mixture, which is beneficial to improve the RAP utilization rate of cold recycled pavement. Proper incorporation of cement can improve the mechanical properties and water stability of cold recycled emulsified asphalt mixture, but it has a certain negative impact on the high temperature performance of cold recycled emulsified asphalt mixture. The suggested cement dosage is 1.5%. [ABSTRACT FROM AUTHOR]

Improvement of snow and ice melting capacity is an important means to ensure driving safety in winter. Phase change asphalt pavement has a wide prospect as an environment-friendly technology. In order to determine whether melting ice and snow of phase change asphalt mixture has practical application value, the phase change process of solid solid phase change materials through a microscope was observed, and the relevant thermodynamic parameters was measured. The pavement performance of phase change asphalt mixture was tested, and three evaluation methods for melting snow and ice were developed. The results show that the solid-solid phase change materials underwent the mutual transformation of crystalline and amorphous states. The difference between the melting enthalpy values in the heat absorption and heat release process was small, both exceeding 70 J/ g, and the 50 times decay rate was 2. 8%, which can meet the long-term use needs of asphalt pavement. With the increase of the amount of phase change material, the high temperature stability of asphalt mixture decreased, the low temperature crack resistance improved, and the resistance to water damage firstly increased and then decreased, but all of them can meet the requirements of the specification. Only when the amount of phase change material exceeded 0. 3%, can it have an obvious ice snow melting effect. It can be seen that solid-solid phase change material can be added to asphalt mixture as an additive. Based on road performance, 0. 3% ~ 0. 5% of phase change material is appropriate. Phase change asphalt mixture is not suiTable for areas where the temperature is lower than 0 ℃ all day, and other snow and ice removal measures need to be combined to ensure road traffic capacity. [ABSTRACT FROM AUTHOR]

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To give full play to the advantages of polyurethane as a binder, such as mixing at room temperature, short curing time, and high curing strength, polyurethane was used as the binder of a waste asphalt mixture, and the pavement performance of PCRM (Polyurethane Cold-Recycled Mixture) was analyzed. Firstly, the adhesion performance of polyurethane binder with new and old aggregates was evaluated using the adhesion test. Then, the mix proportion was designed according to the material characteristics, and the reasonable molding process, maintenance conditions, design indexes, and the optimal binder ratio were proposed. Secondly, the high-temperature stability, low-temperature crack resistance, water stability, and compressive resilient modulus of the mixture were evaluated through laboratory tests. Finally, the pore structure and microscopic morphology of polyurethane cold-recycled mixture were analyzed by industrial CT (Computerized Tomography) scanning, and the failure mechanism of polyurethane cold-recycled mixture was revealed. The test results show that the adhesion between polyurethane and RAP (Reclaimed Asphalt Pavement) is good, and the splitting strength of the mixture increases greatly when the ratio of glue to stone reaches 9%. Polyurethane binder has low sensitivity to temperature and poor water stability. With the increase of RAP content, the high-temperature stability, low-temperature crack resistance, and compressive resilient modulus of PCRM showed a decreasing trend. When the RAP content was less than 40%, the freeze–thaw splitting strength ratio of the mixture was improved. After the incorporation of RAP, the interface was more complex and there were many micron-scale holes, cracks, and other defects; after high-temperature immersion, the polyurethane binder appeared to show a certain degree of peeling at the holes of the RAP surface. After freeze–thaw, the polyurethane binder on the surface of the mixture produced many cracks. The study of polyurethane cold-recycled mixture is of great significance to realize green construction. [ABSTRACT FROM AUTHOR]

To solve the problem of snow on steel bridge areas endangering traffic safety and low road traffic efficiency in winter, conductive gussasphait concrete (CGA) was prepared by mixing conductive phase materials (graphene and carbon fiber) into Gussasphalt (GA). First, through high-temperature rutting test, low-temperature bending test, immersion Marshall test, freeze–thaw splitting test and fatigue test, the high-temperature stability, low-temperature crack resistance, water stability and fatigue performance of CGA with different conductive phase materials were systematically studied. Second, the influence of different content of conductive phase materials on the conductivity of CGA was studied through the electrical resistance test, and the microstructure characteristics were analyzed via SEM. Finally, the electrothermal properties of CGA with different conductive phase materials were studied via heating test and simulated ice-snow melting test. The results showed that the addition of graphene/carbon fiber can significantly improve the high-temperature stability, low-temperature crack resistance, water stability and fatigue performance of CGA. The contact resistance between electrode and specimen can be effectively reduced when the graphite distribution is 600 g/m2. The resistivity of 0.3% carbon fiber + 0.5% graphene rutting plate specimen can reach 4.70 Ω·m. Graphene and carbon fiber in asphalt mortar construct a complete conductive network. The heating efficiency of 0.3% carbon fiber + 0.5% graphene rutting plate specimen is 71.4%, and the ice-snow melting efficiency is 28.73%, demonstrating good electrothermal performance and ice-snow melting effect. [ABSTRACT FROM AUTHOR]

As a new environmentally friendly and recyclable material, recycling construction and demolition waste(CDW) have received extensive attention. If it can be applied in road engineering, it will not only reduce the exploitation of sand and stone, save resources, but also reduce the cost of the project. This is of great significance to the development of highway construction in China. However, compared with natural aggregate, CDW has the disadvantages of low strength and high water absorption. Therefore, there are obvious differences between the CDW subgrade and the traditional subgrade. Based on the existing research results, the basic performance, road performance and settlement degeneration characteristics of CDW in subgrade filling are expounded. Finally, the future research directions are analyzed and prospected, which is helpful to promote the application of construction waste recycling materials in subgrade engineering. [ABSTRACT FROM AUTHOR]

In order to make up the deficiency of the performance evaluation method of solvent cold patching mixture and further study it, firstly, a solvent cold patching asphalt was developed by orthogonal test, then the different preparation processes of cold patching asphalt were analyzed, the performance evaluation method of cold patching mixture was proposed and optimized. Finally, the cold patching mixture made of self-developed cold patching asphalt was compared and verified with three kinds of cold patching mixture sold in the market. The results show that the best preparation process of cold patching mixture is to heat the aggregate, cold patching asphalt and mixing pot to 60 ℃ and then mix. The cold patching mixture made of self-developed cold patching asphalt has excellent low-temperature workability, high initial strength and strong water damage resistance. The proposed evaluation method can better evaluate the road performance of cold patching mixture. The performance evaluation system of cold patching mixture were improved, which can better guide the test design and construction. [ABSTRACT FROM AUTHOR]

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Copyright of China Sciencepaper is the property of China Sciencepaper and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Three types of fog seals with polymer modified-emulsified asphalt were prepared to improve the durability of the fog seal and the maintenance quality of asphalt. Based on the skid resistance, water seepage, and wet wheel abrasion, the spraying scheme of the fog seal was determined. The variation of surface drying time under different temperatures and humidity was clarified. The road performance evolution law of fog seal under composite conditions and long-term abrasion was revealed, respectively. The results show that the optimal spraying amount of modified emulsified asphalt for three types of fog seals was 0.6 kg/m2. The optimal dosage of fine sand for fog seals with waterborne epoxy/polyurethane modified-emulsified asphalt (WER-WPU-JFC-EA) and waterborne epoxy/polyurethane/styrene-butadiene rubber-modified emulsified asphalt (WER-WPU-SBR-EA) was 0.6 kg/m2 and 0.4 kg/m2, respectively. Under average temperature and humidity, the traffic open time of the fog seal was 1.0–1.5 h. After the long-term action of thermal-oxygen/freeze-thaw and climate/freeze-thaw, the bonding strength of WER-WPU-JFC-EA and WER-WPU-SBR-EA fog seal was still greater than 0.34 MPa. After 50,000 times of wear, the mass loss of WER-WPU-JFC-EA and WER-WPU-SBR-EA fog seal was below 5.2 %, maintaining good skid resistance and waterproof performance. • The effective penetration depth of fog seal in asphalt mixtures increases with the increase of specimen porosity. • The impact of environmental temperature and humidity on the surface drying time of the fog seal is opposite. • The mass loss, TD, and the BPN of the fog seal are all exponentially related to the number of wear cycles. [ABSTRACT FROM AUTHOR]

To realize the application of epoxy asphalt concrete on roads and solve the problem of the high cost of epoxy asphalt concrete and the causes of bulging in the construction process, a low-content epoxy asphalt mixture was experimentally studied. Rheological and microscopic tests were carried out to study its performance. At the same time, 17 kinds of low-content asphalt mixture Marshall test pieces and rut plate test pieces with different oil stone ratios were made. Their road performances were tested, and a watertight breathable epoxy asphalt mixture was studied to solve the bulging problem. The research shows that, for ordinary roads, a content of epoxy resin of 10–15% can meet both the high-temperature and the low-temperature requirements. For sections with special rutting resistance requirements, a controlled epoxy resin content between 15 and 30% is recommended. When the content of epoxy resin is greater than 30%, epoxy asphalt initially forms a crosslinked spatial network. An epoxy asphalt with a complex structure from asphaltene to epoxy, with ultra-high performance, can be used for small steel bridge pavements. A BBR test showed that, with an increase in epoxy resin content, the low-temperature performance of asphalt gradually weakens. When the content was 20%, epoxy asphalt’s low-temperature performance was weaker than that of SBS-modified asphalt. Under extremely low-temperature conditions, the performance of epoxy asphalt could not meet the specifications. When the voids of low equivalent epoxy asphalt mixture are controlled at 4.1–4.5%, it is watertight and breathable; this can solve the problem of bulging and greatly reduce the cost of projects.

In the course of asphalt pavement usage, exposure to fuel infiltration accelerates particle detachment, leading to the occurrence of problems such as looseness and peeling. The aim of this study was to comprehensively evaluate the impact of a fuel-resistant modifier (FRM; 1%, 3%, 5%, 7%) on the performance of asphalt and asphalt mixture. Conventional physical tests and high–low temperature rheological tests were conducted on the fuel-resistant modified asphalt (FRMA). The results indicate that, with increased FRM content, the penetration and ductility of FRMA decreased, while the softening point increased. The high-temperature performance improved, but the low-temperature ductility declined. High–low temperature rheological test results demonstrate that the addition of FRM significantly enhanced the asphalt’s shear deformation resistance. A moderate amount of FRM modification improved the asphalt’s low-temperature crack resistance, but excessive FRM resulted in reduced flexibility. In addition, fuel-resistant modified asphalt mixture (FRMAM) specimens were prepared and evaluated for performance. In comparison to the base asphalt, FRM modification enhanced the resistance to oil erosion and peeling as well as the Marshall stability of asphalt mixtures. It reduced the scattering loss caused by fuel dissolution and improved both low-temperature indirect tensile (IDT) strength and high-temperature shear strength. A low content of FRM effectively reduced the sensitivity of asphalt mixtures to fuel infiltration, thus enhancing their road performance.

This study evaluated the performance of bentonite plasticized concrete with good deformation coordination as a road base material, to address the poor deformation coordination of rigid base layers in roads. Through tests such as slump, strength, permeability, and scanning electron microscopy (SEM) and x-ray diffraction (XRD), the study analyzed the variations in workability, mechanical properties, and durability of plastic concrete as a base material under different bentonite and cement contents, as well as the underlying micro-mechanisms. The results showed that plastic concrete exhibited good workability, which improved with increased bentonite and cement content. The 28-day mechanical properties of the plastic concrete met the design criteria for road base layers and had features of higher load-bearing capacity, good toughness, slow strength attenuation, and overall integrity. In durability, the increase of bentonite content enhanced the concrete’s permeability, but decreased abrasivenes and shrinkage. From economic, performance, and engineering perspectives, the optimal bentonite and cement contents for the plastic concrete base were in the ranges of 90 kg m ^−3 to 120 kg m ^−3 and 110 kg m ^−3 to 150 kg m ^−3 , respectively.

To promote the application of bio-materials and provide a direction for their further researches, this paper comprehensively summarizes the research progress of biomaterials in recent years. The review results show that bio-oil is a mixture obtained from different biomasses through pyrolysis, alcoholysis, acidolysis, high liquefaction, etc., and those biomasses mainly include wood fiber type, waste oil type and animal manure type. Bio-binder refers to the product of bio-oil processed by distillation, extraction oxidation and polymer modification, and it can be served as a modifier, diluent or substitute material of asphalt; the main chemical components of bio-oil include ethers, esters, aldehydes, ketones, phenols, organic acids, alcohols and sugars. Bio-asphalt is obtained by adding bio-binder into the petroleum asphalt for modification or blending, and the shear temperature and shear rate of bio-asphalt derived from wood fiber type and waste oil type are usually higher than that of bio-asphalt derived from swine manure. Compared with petroleum asphalt, bio-asphalt binder usually shows lower high-temperature performance as well as higher low-temperature performance and aging resistance. Also, bio-asphalt mixture generally exhibits lower high-temperature stability, higher low-temperature crack resistance and water stability than petroleum asphalt mixture. Future studies should be conducted combining with the source, composition, preparation, properties and oil production rate of bio-oil. First, how to raise the bio-binder content in bio-asphalt as much as possible while ensuring the sufficient performance becomes the focus of future researches. Second, the micro reaction mechanism between bio-binder and petroleum asphalt should be illustrated in depth. Moreover, developing a complete and unifying technical standard and application specification of bio-asphalt technology is necessary for future researches. Furthermore, determining the optimum bio-binder potentially used as the substitute of petroleum asphalt is also an interesting topic.

To solve the problems of low flame retardant efficiency and weak low-temperature performance of asphalt modified by conventional flame retardants (CFR), in this study, halloysite nanotubes (HNTs) and CFR were used to prepare nanocomposite flame retardants (NCFR) to modify asphalt. A fluorescence microscope (FM), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscope/energy dispersive spectrometer (SEM/EDS) were used to characterize the microstructure of NCFR-modified asphalt. An oxygen index meter, Cleveland open cup, and cone calorimeter were used to test the flame retardant properties of the asphalt. A dynamic shear rheometer, bending beam rheometer, and force ductility tester were used to test the rheological properties of asphalt. At the same time, flame retardant–modified asphalt mixtures were prepared to verify the flame retardancy and road performance of the flame retardant–modified asphalt. The research results showed that the asphalt modified with 8% CFR and 1% HNTs (MA/CFR/1% HNTs) showed better dispersibility. The increase of limiting oxygen index and self-ignition temperature and the decrease of heat release rate and smoke production rate of MA/CFR/1% HNTs indicated that it has good flame retardancy. At 64°C, compared with modified asphalt (MA), the rutting factor of MA/CFR/1% HNTs increased by 88.17%, the creep recovery increased, and the irreversible creep decreased, indicating that its high-temperature performance improved significantly. At −18°C , compared with that of MA/CFR, the low-temperature creep stiffness of MA/CFR/1% HNTs decreased by 36 MPa and the creep rate of MA/CFR/1% HNTs increased by 0.034, indicating that only 1% HNTs can improve the effect of degraded CFR on the low-temperature performance of MA. Simultaneously, MA/CFR and MA/CFR/1% HNTs can improve the high-temperature performance and water stability of asphalt mixtures. Adding 1% HNTs to a MA/CFR-modified asphalt mixture can improve the low-temperature performance of the asphalt mixture to the level of the low-temperature performance of the modified asphalt mixture. In summary, the modification of asphalt with 1% HNTs and 8% CFR can effectively improve the flame retardant efficiency and significantly improve the road performance of asphalt. [ABSTRACT FROM AUTHOR]

Copyright of Materials & Technologies / Materiali in Tehnologije is the property of Institute of Metals & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

At present, the resource utilization of solid waste in China is facing prominent problems such as high production intensity, insufficient utilization, and low added value of products. The preparation of biomass composites from biomass solid waste and plastic solid waste reduces not only environmental pollution and energy consumption but also promotes the high-value utilization of solid waste. So, the characterization and preparation experiments of samples with two different biomass are carried out. The wheat straw fiber and corn straw fiber were added into the bio-asphalt mixture with the content of 0.1%, 0.2%, 0.3%, and 0.4%, respectively, with the content of 9% and 12% bio-heavy oil. The physical properties and rheological properties of asphalt were analyzed and evaluated by three indexes and a dynamic shear rheological test. Through the rutting test and immersion Marshall test, heightemperature performance and biological asphalt mixture's water stability were evaluated. The results show that straw fiber can improve bio-asphalt mixture's road performance, especially the performance of high-temperature rutting. When the fiber content of bio-asphalt with 9% bio-heavy oil content is 0.3%, the physical properties and rheological properties of bio-asphalt are the best. Corn straw fiber's influence on bio-asphalt mixture was better than that of wheat straw fiber. [ABSTRACT FROM AUTHOR]

In order to study the road performance of rubber-asphalt mixture with different rubber powder content, in this paper, by adding different quality rubber powder to 70#A grade base asphalt, the asphalt PG grade and the adhesion characteristics between asphalt binder and aggregate were analyzed by asphalt laser rebound test and asphalt contact angle test, determine the optimal rubber powder content of the upper, middle and lower layers of the rubber asphalt pavement structure (30% SMA-13 for the upper layer; 40% for the middle layer AC-20 and 50% for the lower layer AC-25); Through the research on the mechanical properties of the rubber-asphalt mixture with different rubber powder contents, such as the Hamburg rutting test, the low-temperature bending crack resistance test and the direct shear test, the following results are obtained: The addition of rubber powder can enhance the cohesion between the asphalt binder and aggregate, make the plastic deformation ability of the asphalt mixture stronger, effectively improve the water stability and high temperature rutting resistance of different structural layers of rubber-asphalt mixture, improve the crack resistance and fatigue resistance of rubber-asphalt mixture. Combined with engineering examples, borrowing the three-dimensional radar detection system, the internal conditions of the road, such as the integrity of the paving of the rubber mixture asphalt pavement structure layer and the uniformity of the material thickness, were evaluated; Through the on-site road coring and CT scanning, the three-dimensional spatial distribution of aggregates and pores of the on-site pavement structure was obtained, the addition of rubber powder can promote the molecular movement between asphalt binder and aggregate, effectively improve the pore distribution of asphalt mixture, make the material inside the pavement more evenly distributed, give full play to the excellent road performance of rubber asphalt pavement. [ABSTRACT FROM AUTHOR]

To make full use of the regenerative value of waste cooking oil, and to solve the environmental pollution and food security issues caused by waste cooking oil, waste cooking oil was suggested for use in asphalt. Waste cooking oil was used to adjust the performance of virgin and aged asphalt. This review article summarizes research progress on the performance of asphalt and asphalt mixture with waste cooking oil. The results showed that a moderate dosage of waste cooking oil will improved the low-temperature performance and construction workability of petroleum asphalt and aged asphalt. The mixing and compaction temperature of asphalt mixture with waste cooking oil are reduced by up to 15 °C. The rutting resistance and fatigue resistance of modified asphalt and modified asphalt mixture with waste cooking oil are damaged. After the addition of waste cooking oil in aged asphalt, the high-temperature performance and shear rheologic property of aged asphalt will be recovered. The regeneration effect of waste cooking oil on aged asphalt and aged asphalt mixture is close to that of a traditional regeneration agent, and the partial performance of asphalt or asphalt mixture with waste cooking oil is better. There is no chemical reaction between waste cooking oil and asphalt, but the asphalt component and absorption peak intensity of partial functional groups are changed. The light components content of asphalt binder is usually increased. Further research regarding the engineering application of asphalt mixture with waste cooking oil should be conducted. The method for improving the performance of asphalt and asphalt mixture with waste cooking oil will be mainly researched. [ABSTRACT FROM AUTHOR]

In this paper, the key technologies in the construction process of hot in-place recycling were investigated in order to improve the utilization rate of waste asphalt mixture; traditional lab tests including penetration, softening point and ductility tests, atomic force microscope test of recycled asphalt under different rejuvenator content, and the test of milling on grading at different temperatures were carried out. The influence of RAP content and rejuvenation processes on road performance were studied, and the low-temperature performance of mixture was analyzed by the energy analysis method, and the evaluation index was proposed. Test results indicated that the penetration and ductility increases, the softening point decrease with the rejuvenator content increasing, and the optimum rejuvenator content is 4%. The optimum mixing and compaction temperature will decrease by 2–6 °C on average for every 10% increase of RAP content by analyzing the mixture volume index. The results showed enhance rutting resistance of the mixture but lower moisture resistance and low-temperature crack resistance by adding the RAP content. The strain energy density of 10 KJ/m3 is proposed to evaluate the low-temperature performance of the mixture, and 30% RAP produces optimal mixture. The higher rutting resistance and moisture resistance can be obtained by using the construction process of RAP+ rejuvenator co-heating, and higher low-temperature crack resistance with RAP+ rejuvenator without heating. [ABSTRACT FROM AUTHOR]

In order to optimize the ratio of basalt fiber high modulus asphalt mixture and improve its road performance, the response surface method was used to optimize the mix ratio of basalt fiber high modulus asphalt mixture, the performance of optimized basalt fiber high modulus asphalt mixture was analyzed by Marshall test, immersion Hamburg rutting test, low temperature trabecular bending test, immersion Marshall test and freeze-thaw splitting test, the microstructure of the asphalt mixture failure section was observed by scanning electron microscopy(SEM), and the composite enhancement mechanism of basalt fiber and high modulus admixture was tried to reveal. The results show that the optimum ratio of basalt fiber high modulus asphalt mixture obtained by response surface method is 0. 44% high modulus agent, 0. 45% basalt fiber and 4. 98% optimum asphalt aggregate ratio. The road performance test under the best mix shows that the high-temperature stability, low temperature crack resistance, and water stability of the mixture have been greatly improved. It is observed by scanning electron microscopy that the basalt fiber can play a better role in reinforcing and dispersing stress under the action of high modulus agent, and the basalt fiber in the best mix is more evenly distributed in the high modulus asphalt mixture. [ABSTRACT FROM AUTHOR]

To improve the resource utilization of steel slag in road engineering, the chemical composition and immersion expansion rate of steel slag were tested first, and then 40%, 50%, and 60% of 4.75 ~ 16 mm basalt coarse aggregate were replaced by steel slag in drainage asphalt mixes by volume substitution method. To ensure the stability of the drainage asphalt mix structure, the oil-stone ratio was obtained by using raveling test and draindown test. Finally, the rutting and low-temperature trabecular bending tests were conducted on the drainage asphalt mixes with different steel slag dosing. The results show that: the amount of asphalt increases with the increase of steel slag admixture, and the addition of steel slag enhances the high and low-temperature performance of the mix. In terms of the water stability of the mix, the residual stability and the resistance to immersion water raveling loss were enhanced by incorporating the appropriate amount of steel slag. The steel slag adversely affected the freeze-thaw splitting strength ratio and bulk stability of the mixes, but within the specified permissible range. Considering the results of each test, a dosage of 60% steel slag in the drainage asphalt mix is recommended to provide good road performance. [ABSTRACT FROM AUTHOR]

Clear asphalt (CA) currently used in light-colored asphalt mixtures (LCAM) exhibits poor transparency and adhesion. Therefore, a highly transparent CA (HCA) modified using a silane coupling agent (KH550) was prepared. Furthermore, LCAM was prepared by mixing CA and limestone aggregates. The properties of the HCA and ordinary CA (OCA) were characterized using conventional asphalt tests, optical tests, pull-off tests, ultraviolet aging tests, dynamic shear rheometry, Fourier-transform infrared spectroscopy, differential scanning calorimetry, and scanning electron microscopy. Whereas Marshall, moisture resistance, wheel tracking, trabecular bending, and British pendulum tests were employed for the LCAM. The transmittance and spectral reflectance of the HCA were 123.30 and 3.74 times greater than those of the OCA, respectively. The complex modulus and viscosity-aging index of the HCA were 48% and 53% less than those of the OCA, respectively. After modification with KH550, the Marshall stability ratio, tensile strength ratio, and flexural strain of the HCA-prepared LCAM increased by 12.92%, 25.06%, and 23.90%, respectively. However, the rutting resistance of the HCA-prepared LCAM was 14.3% less than that of the OCA-prepared LCAM. The comprehensive performances of the HCA and HCA-prepared LCAM were 49.2% and 10.3% greater than those of the OCA and OCA-prepared LCAM, respectively, indicating a high application value in the future. [ABSTRACT FROM AUTHOR]

Copyright of Transportation Science & Technolgy is the property of Transportation Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to study the pavement performance of polyphosphate (PPA) and liquid styrene butadiene rubber (LSBR) composite modified asphalt and mixture, LSBR with 2.0% content and PPA with 0.3%, 0.6%, 0.9%, 1.2% and 1.5% content are selected for compounding. Penetration, softening point, ductility, rotational viscosity and four component tests are adopted to analyze the basic performance, temperature sensing performance and component changes of the modified asphalt. The road performance changes of the composite modified mixture were studied by rutting test, low temperature trabecular bending test, immersion Marshall test and freeze-thaw cycle test. The results show that PPA can effectively improve the temperature sensitivity and high temperature performance of LSBR modified asphalt; With the increase of PPA content, asphaltene gradually increases and colloid decreases, resulting in the increase of asphalt viscosity; The dynamic stability of PPA/LSBR composite modified asphalt mixture is 77.2% higher than that of LSBR, showing good high temperature performance, Compared with freeze-thaw splitting, the failure strain and freeze-thaw splitting of LSBR are reduced by 6.1% and 2.79% respectively, but it is still 2.0% and 2.3% higher than that of SBS modified asphalt mixture, and its comprehensive performance is the best. [ABSTRACT FROM AUTHOR]

In order to improve the viscoelasticity of waste rubber powder （WCR） modified asphalt, WCR/C9 petroleum resin （C9PR） composite modified high viscosity asphalt binder and its mixture were prepared, the physical properties and storage stability of the modified high viscosity asphalt binder were investigated. At the same time, the properties of its OGFC-13 mixture were evaluated by general road performance test, dynamic creep test, Overlay test and indirect tensile fatigue test, and it was compared with common WCR modified asphalt and commercial high viscosity asphalt binder and their mixture. The results showed that WCR/C9PR high viscosity asphalt had the advantages of high softening point and viscosity, good storage stability and elastic recovery, and its performance was much better than that of common WCR modified asphalt. WCR/C9PR high viscosity asphalt mixture had good high and low temperature performance, water stability, shear deformation resistance, reflection crack resistance and fatigue crack resistance, which was comparable to that of commercial high viscosity asphalt mixtures and could meet the technical index requirements of porous pavements.

In order to raise the utilization rate of industrial waste and mitigate issues involving land resource occupation and environmental damage, in this study, industrial-waste-based artificial aggregates (IWAAs) were fabricated using steel slag powders, fly ash, and cement. They were processed under accelerated carbonation and were utilized in a bitumen mixture. During the experiment, the micromorphology, internal structure, and phase composition of IWAAs before and after accelerated carbonation were characterized using X-ray phase analysis, thermal analysis, and scanning electron microscopy (SEM); concurrently, the possibility of IWAAs being used as a partial substitute for natural aggregate to prepare bituminous mixture was qualitatively and quantitatively analyzed based on Marshall’s design procedure in combination with road performance tests and microcosmic analyses. The results indicated that the presence of carbonate crystals brought about by accelerated carbonation was the main phase composition inside the IWAAs, enhancing the microstructure densification and diminishing the immersion expansion and crushing values; this is due to the depletion of the interior Ca-based (e.g., f-CaO and Portlandite) and Mg-based (e.g., periclase and brucite) compounds together with the formation of cement hydration products. Additionally, the 12 h carbonation time obtained the optimum CO2-sequestration efficiency on the premise of satisfying the performance standard. The expansion rate and crushing value of the IWAAs decreased by 82.21% and 41.58%, respectively, whilst the anti-rutting properties, the moisture damage resistance, and the skid resistance rose by 31.92%, 5.59%, and 10.00%, respectively, in the IWAAs–bituminous mixture. This study lays a foundation for research on the CO2 sequestration and resource utilization of industrial wastes in bitumen mixtures.

To assess the impact of solid waste phosphogypsum on the road performance of lime-fly ash-stabilized red clay, we conducted comprehensive tests on the road performance, swelling and shrinkage characteristics, and mechanical properties of lime-fly ash soil with varying phosphogypsum content and curing age. Additionally, we analyzed the microstructure and composition changes using scanning electron microscopy and X-ray diffraction tests. The results revealed that phosphogypsum significantly enhances the early strength and moisture stability of lime-fly ash soil. The mechanical properties of lime-fly ash soil continue to improve with increased curing age, with performance improvements tapering off after 60 days and eventually stabilizing. Moreover, as the phosphogypsum content increases, the unconfined compressive strength (UCS), splitting strength, and CBR value of the lime-fly ash soil initially increase and then decrease. The optimal mixing ratio was determined to be 4% phosphogypsum, resulting in a 7-day UCS increase of 67.2%, a 28-day UCS increase of 3 times, and a 28-day splitting strength increase of 4.3 times. The moisture stability coefficient also exhibited a 43% increase after 7 days, and its anti-disintegration ability was enhanced, reaching 0.91 after 28 days, which meets the specified standards. Microscopic analysis revealed that the addition of phosphogypsum improved the overall integrity of the lime-fly ash soil, and the formation of ettringite effectively filled the soil’s pores. However, excessive ettringite caused increased expansion and deformation. To optimize the use of phosphogypsum-modified lime-fly ash-stabilized red clay as subgrade filler, it is advisable to incorporate additives to further reduce swelling deformation.