Pavement Performance Of Asphalt Mixture Research Articles

Research on deicing performance and environmental impact of anti-freezing asphalt mixtures

Snow and ice on pavement surface can cause a significant safety concern for drivers. This research investigates the deicing performance of the asphalt mixtures containing a self-prepared salt-storage additive (SSA), as well as their environmental impacts. A pull-off test was developed to evaluate the adhesion between the ice layer and asphalt mixture surface. The self-prepared SSA was incorporated into the asphalt mixtures by replacing mineral filler at percentages of 0 %, 20 %, 50 %, and 100 % by volume. The influence of self-prepared SSA on the pavement performance of asphalt mixtures was firstly investigated in this study, including the high-temperature stability, low-temperature performance, and water stability. The deicing performance of the asphalt mixtures containing self-prepared SSA and commercial product was determined by using the freezing point tests, ice-melting tests, and self-designed pull-off tests. To evaluate the environmental impacts of those anti-freezing asphalt mixtures, corrosion tests and seed germination tests were also employed in this study. Testing results showed that the addition of self-prepared SSA compromised the pavement performance of asphalt mixtures, but all measured properties met the specified requirements. The self-prepared SSA can effectively reduce the freezing point of the asphalt mixtures and shorten the ice melting time by 30 %, which has a similar or even better deicing effect as compared to the commercial salt-storage additive. Notably, the pull-off tests showed that the self-prepared SSA can significantly reduce the adhesion force between ice layer and asphalt mixture surface. The environmental impacts of asphalt mixtures containing self-prepared SSA were found to be within a reasonable range.

Effects of Environment-friendly Polymer Composite Modifiers on the Modulus and Pavement Performance of Asphalt Mixtures

Background: In the current context of low-carbon environment, it is particularly important to use waste plastics to prepare modifiers that increase the modulus of the bituminous mixture. objective: The study aimed to find out the influence of environment-friendly polymer composite modifier (E-FPCM) on modulus and pavement performance of bituminous mixture. Objectives: The study aimed to find out the influence of environment-friendly polymer composite modifier (E-FPCM) on modulus and pavement performance of bituminous mixture. method: The influence of the optimum component E-FPCM on the dynamic modulus (DM) has been explored. The E-FPCM content’s effect on the rheological properties of bitumen has been analyzed. Also, the influence of E-FPCM on pavement performance has been analyzed. Method: The influence of the optimum component E-FPCM on the dynamic modulus (DM) has been explored. The E-FPCM content’s effect on the rheological properties of bitumen has been analyzed. Also, the influence of E-FPCM on pavement performance has been analyzed. Results: The degree of influence on S! of bituminous mixture has been in the order of recycled low-density polyethene (R-LDPE) > aromatic oil > lignin fiber. The optimum composition of E-FPCM has been found to be 10% aromatic oil, 4.8% C9, 62% R-LDPE, 7.0% lignin fiber, 0.2% antioxidant 1076, 2% silane coupling agent, and 14% mineral powder. By using E-FPCM with the optimum components, the SBS bituminous mixture or 90# bituminous mixture has been found to meet the standard of a high-modulus bituminous mixture (HMBM). E-FPCM has been found to reduce the phase angle (δ) of bitumen and increase the complex shear modulus (G∗) and rutting factor [G∗/sin(δ)], which may help improve the rutting resistance (RR). result: According to the degree of influence on S_R of bituminous mixture, recycled low-density polyethene (R-LDPE) > Aromatic oil > Lignin fiber. The optimum composition of E-FPCM is 10% aromatic oil, 4.8 C9, 62% R-LDPE, 7.0% lignin fiber, 0.2% antioxidant 1076, 2% silane coupling agent, and 14% mineral powder. By using E-FPCM with the optimum components, the SBS bituminous mixture or 90# bituminous mixture has been found to meet the standard of a high-modulus bituminous mixture (HMBM). E-FPCM has been found to reduce the phase angle (δ) of bitumen and increase the complex shear modulus (G∗) and rutting factor [G∗/sin(δ)], which may help improve the rutting resistance (RR). conclusion: E-FPCM is beneficial for improving the RR of the bituminous mixture, and reasonable content of E-FPCM has a great role in improving the water stability (WS) and low-temperature crack resistance (LTCR) of the bituminous mixture. Conclusion: E-FPCM is beneficial for improving the RR of the bituminous mixture, and reasonable content of E-FPCM has a great role in improving the water stability (WS) and low-temperature crack resistance (LTCR) of the bituminous mixture.

Biomass valorization toward sustainable asphalt pavements: Progress and prospects

To cope with the global climate crisis and assist in achieving the carbon neutrality, the use of biomass materials to fully or partially replace petroleum-based products and unrenewable resources is expected to become a widespread solution. Based on the analysis of the existing literature, this paper firstly classified biomass materials with potential application prospects in pavement engineering according to their application and summarized their respective preparation methods and characteristics. The pavement performance of asphalt mixtures with biomass materials was analyzed and summarized, and the economic and environmental benefits of bio-asphalt binder were evaluated. The analysis shows that pavement biomass materials with potential for practical application can be divided into three categories: bio-oil, bio-fiber, and bio-filler. Adding bio-oil to modify or extend the virgin asphalt binder can mostly improve the low temperature performance of asphalt binder. Adding styrene-butadienestyrene (SBS) or other preferable bio-components for composite modification will have a further improved effect. Most of the asphalt mixtures prepared by using bio-oil modified asphalt binders have improved the low temperature crack resistance and fatigue resistance of asphalt mixtures, but the high temperature stability and moisture resistance may decrease. As a rejuvenator, most bio-oils can restore the high and low temperature performance of aged asphalt and recycled asphalt mixture, and improve fatigue resistance. Adding bio-fiber could significantly improve the high temperature stability, low temperature crack resistance and moisture resistance of asphalt mixtures. Biochar as a bio-filler can slow down the asphalt aging process and some other bio-fillers can improve the high temperature stability and fatigue resistance of asphalt binders. Through calculation, it is found that the cost performance of bio-asphalt has the ability to surpass conventional asphalt and has economic benefits. The use of biomass materials for pavements not only reduces pollutants, but also reduces the dependence on petroleum-based products. It has significant environmental benefits and development potential.

Development and characterization of permeative anti-rutting agent for asphalt mixture enhancement

Rutting distress has adverse effects on driving safety and comfort. However, how to enhance the rutting resistance of specific pavement sections contrapuntally and flexibly still requires further study. A permeative anti-rutting agent (PARA) based on epoxy resin and Buton rock asphalt was developed in this study to enhance the rutting resistance of asphalt pavement. It can improve the rutting resistance by permeating and curing in the asphalt pavement. Its optimum composition was characterized and determined at first. PARA’s effect on pavement performance of asphalt mixture was then tested and analyzed. Results suggested that the optimum mass proportion of epoxy resin, curing agent, curing accelerator and Buton rock asphalt was determined as 1.6:1:0.02:0.32. The lowest exudative percentage of PARA was found when its content was 0.9%. Higher PARA content will result in lower void volume and void in mineral aggregate of asphalt mixture. The mixture’s Marshall stability, moisture resistance, and dynamic stability were positively correlated to PARA’s content. The lowest flexural tensile strain and flexural tensile strength in low temperature occurred when PARA content was 0.9%. Asphalt mixture with 0.90% PARA showed optimum fatigue performance and aging resistance. Therefore, PARA can be used to enhance the asphalt pavement at low cost. Its advantage in flexibility and convenience results in its excellent application prospect.

Experimental investigation on the performance of the asphalt mixture with ceramic fiber

Ceramic fiber (CF) as a kind of industrial waste is widely used for the sake of waste utilization and environmental protection. In this study, three kinds of industrial waste ceramic fibers, CF-A (NC1260 spinning CF), CF-B (NC1260 blowing CF), and CF-C (NC1430 spinning CF), were used to develop a ceramic fiber modified asphalt mixture (CFMAM) to meet the increasing demand for asphalt pavement construction. Firstly, the optimum asphalt content of the CFMAM was determined by the mix design with the 0.3%wt fiber content. Secondly, the high-temperature stability and low-temperature cracking resistance of CFMAM were evaluated by rutting test, beam bending test and splitting test, respectively. The results showed that the CF-A and CF-C had the same positive influences on the mechanical properties and pavement performance of asphalt mixture, while the CF-B exhibited fewer positive influences. Then, the moisture susceptibility performance was tested by immersed Marshall test and freeze-thaw splitting test. The CFMAM with CF-A showed better properties than that of CF-B, CF-C, and virgin asphalt binder. Finally, the scanning electron microscopy (SEM) experiment was conducted to analyze the adsorption effect of fiber on asphalt mortar and the reinforcement effect on the mixture. It was observed that the fiber and asphalt had good wettability and dispersibility in the mixture.

A new flame retardant and its effect on the asphalt mixture

To alleviate the problem of decomposition products of organic flame retardants with toxic, inorganic flame retardants were used to prepare flame retardant modified asphalt (FRA), but the traditional inorganic flame retardants have a significant flame retardancy only with a high dosage, and too high dosage would bring serious adverse effects on the pavement performance of asphalt mixture. For this, to avoid the side effects of inorganic flame retardants, a compound flame retardant was developed by orthogonal experiment method to alleviate the problem of high dosage of inorganic flame retardants, and to have a relatively significant flame retardancy. The flame retardancy was studied by conventional performance test, separation test, rotational viscosity (RV) test, dynamic shear rheology (DSR) test, limiting oxygen index (LOI) test, thermogravimetry (TG) test, pavement performance test, and combustion test. The results show that with the addition of self-developed flame retardant (WZRJ-I), the PI of FRA was increased by 23.4∼40.4 % compared with virgin asphalt, the LOI was increased by 24.7∼46 %, the rutting factor was increased by 12.6∼27.9 %, the thermal decomposition parameters were significantly improved at all stages, the burning time was reduced by 39 s∼53 s, the mass loss was reduced by 11.9∼15.4 %, which indicated that the addition of WZRJ-I was conducive to improve the flame retardancy and high temperature performance. Finally, the prediction equation model of combustion performance index and burning time of asphalt mixture was established, and the effect of burning time on the residual pavement performance of asphalt mixture was quantitatively analyzed.

Influence of low-temperature polyurethane solid-solid PCMs particles on the pavement performance of asphalt mixtures

In order to slow down the cooling rate of the mixture and reduce the low temperature cracking of asphalt pavement in large temperature difference areas, low-temperature polyurethane solid-solid phase change materials (LPSPCMs) were prepared by prepolymer method. The researches show that LPSPCMs have good phase change heat storage performance and thermal stability performance, and can be applied to hot mix asphalt mixtures. The LPSPCMs particles were incorporated into the asphalt mixture, and the road performance of the LPSPCMs particulate asphalt mixture was tested and analyzed and found: as LPSPCMs particles change the abrasion resistance and embedded effect between asphalt mixes, with the increase of LPSPCMs particles, the high-temperature performance of asphalt mixes first increased and then decreased. The water stability of asphalt mixtures gradually decreases with the increase of LPSPCMs particles content because relative to limestone aggregates, LPSPCMs particles adhere poorly to asphalt. The thermal stress restrained specimen test (TSRST) showed that the cracking temperature of the asphalt mixture gradually decreased with the increase of LPSPCMs particles contents because of the phase change temperature control effect of LPSPCMs particles indicated that LPSPCMs particles improve the low-temperature performance of asphalt mixtures. On this basis, the correlation between the evaluation index of the phase change temperature adjustment effect and the improvement effect of the low-temperature performance of the mixture was established.

Effects and Reaction Mechanism of Acid Rain on the Pavement Performance of Asphalt Mixtures with Steel Slag Aggregates

Effects and Reaction Mechanism of Acid Rain on the Pavement Performance of Asphalt Mixtures with Steel Slag Aggregates

Influence of salt dissolution on durable performance of asphalt and Self-ice-melting asphalt mixture

At present, research on the influence of salt dissolution on pavement performance of self-ice-melting asphalt mixture is scarce. Based on laboratory research, this study aims to investigate the influence of salt dissolution on the durable performance of asphalt and self-ice-melting asphalt mixture. Firstly, SBS modified asphalt binder containing Mafilon (MFL) and self-ice-melting asphalt mixture (SMA-13) containing MFL and rubber particles (RP) were subjected to dry-wet cycles for different cycles. Then the influence of salt dissolution on the properties of asphalt and its mechanism were studied by physical properties test, scanning electron microscopy (SEM) test, energy dispersive spectrometer (EDS) test and Fourier transform infrared spectroscopy (FTIR) test. Finally, the influence of salt dissolution degree on long-term pavement performance of asphalt mixture was evaluated by freeze–thaw splitting test, rutting test, and trabecular bending test. The experimental results showed that with the increase in the number of dry-wet cycles, the penetration and ductility of asphalt decrease, while the softening point increases. The greater the content of MFL and the increasing number of dry-wet cycles, the greater the variation is. The effect of salt dissolution on asphalt properties can be attributed to salt aging and physical effect, without chemical reactions occurring. In addition, the road performance test of asphalt mixture indicated that the decrease of water stability, high-temperature performance, and low-temperature performance of self-ice-melting asphalt mixture increases firstly and then tends to be gentle as the increase of salt dissolution. What’s more, the water stability is deeply influenced by salt dissolution.

Synthesis and Characterization of Calcium Alginate Capsules Encapsulating Soybean Oil for In Situ Rejuvenation of Aged Asphalt

Asphalt aging is a major cause of distresses in asphalt pavement, seriously decreasing the in-service performance and shortening the lifetime of pavement. Traditional asphalt rejuvenating methods usually consume a great deal of worker and energy resources. This study encapsulated rejuvenator to automatically realize in-situ rejuvenation of aged asphalt in pavement. Soybean oil was selected as the asphalt rejuvenator, and its effectiveness in rejuvenating the aged asphalt was identified. Then it was encapsulated into three kinds of calcium alginate capsules by the orifice coagulation bath method. Next, the micromorphology, internal structure, density, mechanical strength, and thermal stability of the capsules were characterized using digital microscopy, stereomicroscope, graduated cylinder test, uniaxial compressive test, and thermogravimetric analysis, respectively. The effects of the capsules on the pavement performance of asphalt mixture were analyzed. Test results showed that the soybean oil effectively recovered the properties of the short-term aged asphalt binder at an optimum content of 2% by binder mass, and it was encapsulated successfully in capsules with diameters of about 2 mm. There were many slight bumps and indentations on the capsule surface, and many pores filled with soybean oil inside the capsule. The density of the capsules was close to that of the asphalt binder, providing a favorable condition for their uniform distribution in the asphalt mixture. It was proved that the capsules can resist the mechanical and thermal conditions during road construction. The pavement performance of asphalt mixture containing capsules still met the requirement of the specification in China. The findings of this paper are helpful to prolong the service life of asphalt pavement and reduce the maintenance costs in the long run, ultimately contributing to the development of smart and sustainable pavement.

Effect of TiO2/CeO2 on Photocatalytic Degradation Capability and Pavement Performance of Asphalt Mixture with Steel Slag

AbstractPhotocatalytic pavements materials are being developed to purify toxic automobile exhaust gas, especially in tunnels where the pollution concentrations are high. This study investigated the...

Adhesive behavior and pavement performance of asphalt mixtures incorporating red mud as a filler substitute

With the massive exploitation and utilization of no-renewable natural resources, good-quality road building materials has been becoming scare and it is an urgent demand to explore and develop alternatives. This study investigated feasible approaches of using red mud as a filler substitute to replace limestone powder in asphalt mixtures. In order to elaborate its influence on adhesive behavior, surface energy components of various fillers, base bitumen, the powder-bitumen interface and the aggregate-asphalt mastic interfaces were calculated and characterized. The mechanical properties of asphalt mastics and asphalt mixtures were assessed by using Quality Control Test (QCT), Hamburg Wheel Tracking (HWT) test and Simple Performance Test (SPT). Referring to the thermodynamic theory, the adhesive performance of the red mud-bitumen interface can be improved by the addition of hydrated lime or Portland cement and the moisture resistance of the aggregate-asphalt mastic bond can be enhanced. It was found that incorporating the red mud can improve the stiffness and the elastic recovery of asphalt mastic, which in turn had a potential to improve the high-temperature performance of the corresponding asphalt mixtures. Regarding to pavement performance, replacing limestone powder by red mud improved the rutting resistance of asphalt mixtures and the moisture resistance can be enhanced by incorporating a certain amount of hydrated lime or Portland cement.

Morphology and properties changes of virgin and aged asphalt after fusion

The aging of asphalt seriously affects the pavement performance of asphalt mixtures. In this study, we investigated the changes in virgin and aged asphalt during the regeneration process of aging asphalt using atomic force microscopy (AFM), Fourier transform infrared (FTIR) spectrometer, and dynamic shear rheometry (DSR). Dynamic modulus tests were carried out for asphalt mixtures containing 30% and 50% reclaimed asphalt pavement. Comparatively DSR tests were performed to determine the complex shear modulus for asphalt binder blends containing 30.6% and 51% aged asphalt. Based on the Hirsch model, the predicted and measured values of the dynamic modulus were compared to obtain a macroscopic evaluation of the degree of virgin and aged asphalt fusion. The results show that the virgin and aged asphalt are fused with high uniformity. From AFM scans, with increase in virgin asphalt content, the size of the bee-like structure decreased and the number increased. This was reflected in roughness indexes (Rq, Ra, Pbee-like, and Rmax) exhibiting gradually decrease, tending more to the microstructure of virgin asphalt with increasing virgin asphalt content. FTIR results showed that the carbonyl index and sulfoxide index decreased as the virgin asphalt content increased, which was consistent with the AFM test results. With addition of an optimal amount of regenerant the microstructure and high-temperature rheological properties of aged asphalt were positively altered. The improvement in the microstructure and rheological properties of rejuvenated aged asphalt was found to be similar to that of blends altered with 49% of virgin asphalt. With the increase in the content of virgin asphalt, the complex shear modulus of the asphalt G*, the rutting resistance of asphalt G*/sinδ was found to decrease as δ increased. The comparison between the predicted and measured dynamic modulus value confirms the successful fusion of the virgin and aged asphalt from a macro perspective. The macroscopic and microscopic analysis results of the change law of virgin and aged asphalt fusion are consistent.

Effect of expanded graphite/polyethylene glycol composite phase change material (EP-CPCM) on thermal and pavement performance of asphalt mixture

The application of phase change materials (PCMs) to the temperature regulation of asphalt pavements has recently become a hot topic of research. At the same time, studies concerning the influence of PCMs on the thermal and pavement performance of asphalt mixtures are still rarely available. The primary objective of this study was to reveal the effect of an expanded graphite/polyethylene glycol composite phase change material (EP-CPCM) on the thermal and pavement performance of asphalt mixtures. EP-CPCM was incorporated into an AC-13 asphalt mixture at various dosages. First, the thermal performance, including thermal constants and thermal regulation effects of the EP-CPCM-modified asphalt mixtures was evaluated, followed by an investigation of the pavement performance in terms of rutting and cracking resistance, moisture stability, and fatigue resistance. The results indicate that by reducing the heating and cooling rates as well as extending the heating and cooling times, EP-CPCM can regulate the temperature of asphalt pavements. The thermal balance inside the pavement and heat exchange between pavement and the ambient environment also improved. The rutting resistance and cracking resistance of asphalt mixtures were enhanced, mainly when the dosage of EP-CPCM was limited. However, the adverse effects of EP-CPCM on the moisture stability under hot water conditions, freeze-thaw conditions, fatigue life, and stress sensitivity gradually emerged when the dosage of EP-CPCM increased.

Evaluation of cooling effect and pavement performance for thermochromic material modified asphalt mixtures under solar radiation

The thermal effect of asphalt pavements on the surrounding environment in summer is of increasing concern since they absorb a great deal of heat from solar radiation and contribute greatly to the urban heat island effect. A novel thermochromic material modified asphalt binder is proposed to modulate pavement temperature by reversibly changing colors and reflectivity to solar radiation in response to temperature variations. In this study, an attempt is extended into the mixture scale. The cooling effect and pavement performance of thermochromic material modified asphalt mixtures are evaluated using a proposed solar radiation simulation test and various mechanical tests. The thermochromic material modification mechanism is revealed from the physical and chemical points of view. It is found that the addition of thermochromic additive to base binders has a significant cooling effect on asphalt pavements in summer. The maximum temperature reduction is observed at the bottom of the top asphalt layer and the top of the middle asphalt layer. Two types of thermochromic additives show positive and negative effects on rutting resistance. Thermochromic material modification has little effect on low-temperature cracking resistance and all thermochromic material modified mixtures exhibit good moisture stability. Preliminary recommendations on the optimum additive type and content of thermochromic material are proposed. The characteristics of coating, dispersion, and intactness of thermochromic additives in base binders significantly affect the pavement performance of asphalt mixtures. The particle size of the thermochromic additive and the chemical composition of shell material are critical to binder modification.

Performance Characterization of Hot Mix Asphalt with High RAP Content and Basalt Fiber.

Incorporating reclaimed asphalt pavement (RAP) into asphalt mixtures achieves astonishingly environmental and economic benefits. However, there is hesitation to use higher RAP content due to the concern regarding the deterioration in pavement performance, especially the cracking resistance. Basalt fiber has been considered an effective additive to reinforce the performance of asphalt mixtures and, subsequently, the reinforcement effect is also expected for high-RAP content mixtures. Therefore, this study investigated the effect of basalt fiber on the pavement performance of asphalt mixtures with 0%, 30%, 40%, and 50% RAP contents against high-temperature performance, moisture susceptibility, low-temperature and intermediate-temperature cracking resistance, based on the wheel-tracking test, the uniaxial penetration test, the freeze-thaw splitting test, the low-temperature bending beam test, the semicircular bend fracture test and the indirect tensile asphalt cracking test, respectively. In addition, a performance-space diagram was developed to determine the mixture performance shift caused by basalt fiber. The results showed that adding basalt fiber compensated for the detrimental effect caused by RAP, leading to significant enhancement in moisture susceptibility and low- and intermediate-temperature cracking resistance of mixtures with high RAP content, along with the enhancement in high-temperature performance, indicating that basalt fiber can contribute to the use of high RAP content.

Investigation on characteristics and properties of bagasse fibers: Performances of asphalt mixtures with bagasse fibers

Bagasse from sugar industry waste contains plenty of nature fiber materials and the application of nature fibers in hot mix asphalt has become a more attractive alternative for the construction of road pavement. The aim of this work focuses on investigating the characteristics of bagasse fibers and performances of asphalt mixtures blended with bagasse fibers, compared with lignin fibers. The microstructure, components and properties of bagasse fibers were studied by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectrometer (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The oil absorbing test and heat resistance test were carried out to evaluate the adsorbability and heat resistance of bagasse fibers. In addition, the Marshall stability, high temperature stability, low temperature cracking resistance and water susceptibility of AC-13 and SMA-13 mixtures blended with fibers were comparatively evaluated by a series tests. Results show that the bagasse fibers have corrugated surface and irregular lumens and contain cellulose, hemicellulose, and aromatic polymers, mostly composed of amorphous and natural polysaccharide components similar to lignin fibers. The thermostability of bagasse fibers is slightly better than that of lignin fibers while the adsorbability of the latter is greater than that of the former. The high temperature stability and low temperature cracking resistance of asphalt mixtures can be greatly improved by adding bagasse fibers. The pavement performances of asphalt mixtures with bagasse fibers are basically close to that of asphalt mixtures with lignin fibers. Hence, bagasse fibers can be described as an environmentally friendly alternative for future pavement construction.

物理改性赤泥替代矿粉的沥青混合料路用性能研究

物理改性赤泥替代矿粉的沥青混合料路用性能研究

Performance Evaluation of Styrene-Butadiene-Styrene-Modified Stone Mastic Asphalt with Basalt Fiber Using Different Compaction Methods.

Superpave gyratory compaction (SGC) and Marshall compaction methods are essentially designed according to volumetric properties. In spite of the similarity, the optimum asphalt contents (OAC) of the two methods are greatly affected by the laboratory compaction process, which would further influence their performance. This study aims to evaluate the performance of styrene-butadiene-styrene (SBS)-modified stone mastic asphalt (SMA) with basalt fiber by using SGC and Marshall compaction methods. Basalt fiber was proved to improve and strength the basic properties of SBS-asphalt according to test results of asphalt binder. The effects of SGC and Marshall compaction methods on OAC and volumetric properties, i.e., density, air voids (VA), voids in mineral aggregates (VMA), and voids filled with asphalt (VFA), were evaluated in detail. Finally, the pavement performance of asphalt mixture prepared by SGC and Marshall compaction methods were compared in order to analyze the high-temperature creep, low-temperature splitting, and moisture stability performance. Results showed that the OAC of SGC (~5.70%) was slightly lower than that of Marshall method (5.80%). Furthermore, the pavement performance of SGC specimens were improved to a certain extent compared with Marshall specimens, indicating that SGC has a better compaction effect and mechanical performance.

Influence of NiTi alloy phase change heat-storage particles on thermophysical parameters, phase change heat-storage thermoregulation effect, and pavement performance of asphalt mixture

Phase change material is a high thermal storage substance, which can reduce temperature-related diseases of asphalt pavement when mixed with asphalt mixture. In this paper, NiTi alloy phase change heat-storage asphalt mixture (NiTi APCHAM) are prepared by using equal volume parts to replace fine asphalt aggregates partially with the NiTi alloy phase change energy-storage particles (NiTi APCEP). As the temperature increases, the specific heat capacity of NiTi APCHAM will increase first and then decrease due to the heat-storage effect of NiTi APCEP. The thermal conductivity coefficient of NiTi APCHAM shows a linear increasing trend with the increase in the substitution rate of NiTi APCEP. Adding NiTi APCEP in asphalt mixture can reduce its daily maximum temperature. Increasing admixture of NiTi APCEP in asphalt mixture can help to improve the phase change heat-storage thermoregulation capacity of the mixture. However, at a 6 wt% substitution rate of NiTi APCEP, the latent heat thermoregulation efficiency of NiTi APCEP reaches to maximum. With the increase in the content of NiTi APCEP, the Marshall stability of asphalt mixture gradually increases, and flexural-tensile strain at low temperature decreases gradually. By contrast, the water stability of the asphalt mixture is unaffected by the addition of NiTi APCEP.