Polymer-modified Asphalt Research Articles

Systematic Review of Plastic Waste as Eco-Friendly Aggregate for Sustainable Construction

The advent of the COVID-19 pandemic has increased the amount of plastic waste. The demand for food and plastic-packaged foodstuffs has increased, and the use of disposable utensils has increased. The large usage of plastic packaging was the main factor which contributed to the plastic waste disposal. Since these plastic wastes are not easily degraded, it has led into massive environmental pollution. Transitioning towards eco-friendly materials fornewsustainabletechnologieswillbecriticaltocombatingfuturepandemicsandreducetheplasticwaste.Hence, recycling of plastic waste and its re-utilization as green and eco-friendly construction material could decrease the tendency of environmental pollution. In this review paper, we have presented an overview of the published articles which recycled plastic waste as an eco-friendly aggregate material for different construction-based applications before COVID 19 and during COVID 19. Furthermore, the processing methods which were suggested in the published articles for recycling plastic waste have been discussed. A few construction materials could be developed by utilizing the plastic wastes, including the polymer-modified asphalt mixes, eco-bricks, and construction and demolitionmaterials.Theseproductscouldbeusedasnovelproductsfor othersustainableapplicationsandbenefits of circular economy. According to several reports, polymeric based plastic wastes can be effectively used as a recycledmaterial,decrease the demand for traditional material sandal so tremendously reduce the construction costs.

Property transitions of neat and styrene–butadiene-styrene (SBS)-modified asphalt binders from small, medium to large-amplitude oscillatory shears

ABSTRACT Tests on asphalt binder are typically performed in its linear viscoelastic (LVE) range. In this research, the rheological properties of neat and styrene–butadiene-styrene (SBS)-modified asphalt binders were examined from 0.01% to 1000% at a high usage temperature, and focus was placed on their non-linear viscoelastic (NLVE) behaviours. Experimental variations and binder property changes in small, medium and large-amplitude oscillatory shears were revealed. Besides strain amplitude, the effects of polymer content, short-term aging and test frequency on NLVE behaviours were also analysed based on three quantitative methods. Additionally, polymers in asphalt binders were examined by using confocal fluorescence microscopy. The NLVE behaviours were found to be affected by shear strain amplitude, polymer content, shear frequency, and the interactions of such factors, but to a less extent by short-term aging. Besides polymer content, the size and morphology of polymer phase likely affect the property variations of modified asphalt binders. Large amplitude oscillatory shear (LAOS) test and morphology analysis help identify the threshold polymer content in producing high-quality polymer-modified asphalt binders.

Study of the Effect of Climatic Factors on Indirect Tensile Strength of Asphalt Mixtures Modified with a Mixture of /Polymer-Sulfur/

The asphalt paver must fulfill a set of basic requirements, from a sufficient bearing capacity for the expected loads, stability and good resistance to deformations resulting from the passage of large loads at high temperatures, and also securing an impermeable surface that achieves adequate and good drainage of water. Hence, it is necessary to search for permanently and continuously improved materials that are resistant to the influence of factors affecting the flexible paving in its upper layers, consisting of bituminous composites. Polymer-modified bitumen has been used to improve the performance of bituminous paving. I have designed asphalt mixtures using asphalt cement without modification, polymer-modified asphalt cement (polyethylene), and asphalt cement modified with a mixture of (polymer-sulfur). Next, I performed lab experiments simulating the effect of investment, weather and climatic factors during operation and investment (conditioning test). It is concluded that the change in the value of indirect tensile Strength for the Asphalt samples formed using an asphalt cement which modified with a mixture of /polymer-sulfur/ was (4%) of its value after the conditioning test, and as for Asphalt samples formed using an asphalt cement which is modified with polyethylene (PE), the value was (14%) after the conditioning test cement which is modified with polyethylene (PE) the value was (14%) after the conditioning test.

Bituminous pavement sustainability improvement strategies

Transportation systems have enormous challenges in terms of sustainability since they deal with issues like economic, environmental, and social factors, and pavement sustainability is unavoidably one of these problems. This study investigates pavements' sustainability potential, and in doing so, it looks at both global practices and personal experiences. This research investigates the long-term viability of pavements. Some of the topics covered in this course are: Recycled Concrete, Recycled Asphalt Pavement, Bio-binders of asphalt, asphalt cement, warm mix asphalt, tack coat, rubberized asphalt (RA), polymer modified asphalt (PMA), and sustainability in pavement design. According to the findings, research is needed to provide environmental sustainability training, including preservation and maintenance solutions. Carbon sequestration and resource regeneration are environmental sustainability elements that need to be considered when selecting treatment options for pavement preservation. Recycled or alternative materials must be found for pavement preservation and maintenance techniques. Finally, research is urgently needed to assess the environmental advantages of asphalt crack sealing. It is thus imperative that any new studies on pavement incorporate sustainable pavement management components.

Full-Scale Pavement Testing of a High Polymer-Modified Asphalt Concrete Mixture

Abstract This paper presents the validation process for the structural layer coefficient determined mechanistically for high polymer (HP) asphalt mixtures (i.e., 0.54) through full-scale laboratory testing of asphalt pavements. Two instrumented full-scale pavement experiments were conducted in the PaveBox setup at the University of Nevada, Reno. A flexible pavement structure with a conventional polymer-modified asphalt layer was evaluated in Experiment No. 1. Meanwhile, a flexible pavement structure with a reduced-thickness HP asphalt concrete (AC) layer was evaluated in Experiment No. 2. Similar vertical surface deflections (except under the center of the applied surface load), higher vertical stresses at the middle of the base layer, and similar vertical stresses below the subgrade surface were observed with the reduced thickness of the HP AC layer. Moreover, better overall fatigue and rutting performance in the AC layer, slightly higher rut depths in the unbound layers, and similar total rut depths were observed by means of mechanistic analysis with the use of HP AC pavement. In general, the results and findings of this study supported the selection of 0.54.

Effect of Aged Binder Distribution on the Fracture Tolerance of Asphalt Mixtures with Reclaimed Asphalt Pavement

Abstract This study investigated the effect of the distribution of aged binder from reclaimed asphalt pavement (RAP) on the fracture tolerance of recycled asphalt mixtures. Two RAP sources (one coarse, one fine), one virgin polymer-modified asphalt binder, and four RAP contents (0 %, 20 %, 30 %, and 40 %) were used to produce a total of seven mixtures. Fracture tolerance was assessed in terms of fracture energy density (FED) at three levels: binder, interstitial component (IC) (composed of effective binder and fine aggregate fraction), and mixture. Binder fracture energy tests were conducted to measure the FED of blends of virgin and recovered RAP binder. IC direct tension tests were employed to determine the IC FED. Finally, Superpave indirect tensile fracture tests were performed to obtain the FED of RAP mixtures. FED decreased with increasing RAP content at the three levels (binder, IC, and mixture). More importantly, IC and mixture exhibited almost identical FED reductions in relative terms, while the reduction was less significant at binder level. This finding indicates that the full blending scenario artificially created at the binder level did not occur at IC and mixture levels. Furthermore, the coarse RAP yielded greater FED than the fine RAP, which substantiates that RAP gradation controls the distribution of RAP binder in recycled mixtures. Consequently, the lower content of aged RAP binder in the IC portion for mixtures with the coarser RAP resulted in better fracture tolerance. The application of a newly developed guideline for determining the maximum allowable RAP content in recycled mixtures confirmed that the coarser RAP used in this study allows for a greater RAP content than the finer RAP despite the stiffer RAP binder.

Field calibration and validation of a pavement aging model

ABSTRACT A pavement aging model (PAM) is established by calibrating and validating the NCHRP 09–54 kinetics model's predictions against field core measurements. Field cores, laboratory-mixed loose mixtures, and binders from a wide range of pavement sections are used, including both conventional hot mix asphalt (HMA) mixtures and modern materials (i.e. reclaimed asphalt pavement (RAP), warm mix asphalt (WMA), and polymer modified asphalt (PMA)). Field aging levels are measured at different depths from binder extracted and recovered from in-service field cores. The original component materials of these pavement sections are aged in the laboratory and used to calibrate the kinetics model. The measured field aging levels are compared against those predicted from the kinetics model to inform a depth and time dependent field calibration function for the PAM. The validation of PAM using an independent set of field sections shows that, within the limited data used in this study, the calibrated PAM may be able to predict the aging of the conventional HMA, RAP, WMA, and PMA mixtures. The PAM predictions are lastly found to outmatch the predictions by the Global Aging System (GAS) model.

PERFORMANCE EVALUATION OF ETHYLENE-VINYL ACETATE MODIFIED BITUMEN AND MIXTURES

Interconnectivity necessitates the use of transportation facilities and infrastructure. All highway design agencies seek acceptable, long-lasting, and cost-effective strategies while designing these facilities. The traffic demands on roads are much higher than they have been in the past. Increased traffic loads, larger traffic volumes, and insufficient maintenance have all contributed to serious road surface distress (e.g., rutting and cracking) due to rapid development. As conventional asphalt combinations are unable to withstand high axle loads and tire pressures, interest in polymer-modified asphalt has grown. Polymer modification of asphalt is one of the most effective ways to improve asphalt qualities. The practical temperature range of binders is greatly expanded by polymers. The inclusion of the polymer can considerably improve the binder qualities by increasing the stiffness of the bitumen and enhancing its temperature susceptibility, enabling the building of safer roads and lower maintenance costs. This research presents a laboratory investigation of the Ethylene Vinyl Acetate (EVA) polymer-modified bitumen. NHA-B gradation, PARCO 60/70 grade bitumen, and EVA polymer of TPI Polene Public Company Limited were used. Penetration, softening point, ductility, and viscosity tests were used to evaluate the conventional properties of the asphalt binders. Three different percentages of polymers were used i.e., 2%, 4%, and 6%. The impact of the EVA polymer on permanent deformation and moisture susceptibility was investigated. A double wheel tracker (DWT) was used to quantify permanent deformation (rutting), and a Universal Testing Machine (UTM) was used to examine moisture susceptibility using an Indirect Tensile Strength (ITS) test. For different percentages of bitumen volumetric properties according to Marshall Mix Design procedure were measured, and then Optimum Bitumen Content (OBC) was evaluated. Performance tests were performed using above mentioned percentages of EVA. The rutting potential of mixes was improved by the addition of EVA as compared to control asphalt mixes. The same effect of the polymer was on the moisture susceptibility of the prepared samples. This showed that EVA polymer can be used in flexible pavements to reduce permanent deformation and high-temperature problems.

Evaluation of the use of a HiMA binder to extend the durability of porous friction courses (PFC)

ABSTRACT Porous friction courses (PFC) are thin layers of asphalt mixtures with open gradations and high air void contents, which are placed over conventional flexible pavements. Although they improve various safety and environmental issues, their main difficulty is their short service life. A common practice to enhance PFC durability is the use of modified asphalt binders (e.g. regular polymer-modified asphalt (PMA) or asphalt rubber). However, this approach has not been enough to achieve life-spans close or equal to those of dense-graded hot mix asphalt. The use of highly polymer-modified asphalts (HiMA), which are binders modified at polymer doses near 7–8% by total weight of the binder, constitutes an alternative to overcome this challenge. This work evaluates the mechanical performance of four PFC mixtures fabricated with a regular polymer modified (PMA) and a HiMA binder, and two aggregate sources. The experimental plan included the semicircular bending (SCB), IDEAL-CT, Cantabro abrasion loss and Tensile Strength Ratio (TSR) tests at intermediate temperatures and various ageing conditions. Results indicate an enhanced cracking and degradation resistance for PFC mixtures containing HiMA and suggest that the use of this type of asphalt binder could increase the service life of these mixtures.

Preparation and characterization of CQDs/SBS composites and its application performance as asphalt modifier

This research aims to use the prepared bio-base carbon quantum dots/styrene–butadiene styrene block copolymer (CQDs/SBS) composite materials as asphalt modifiers based on Pickering emulsion polymerization. The physical and chemical properties of CQDs/SBS composite modifier and its effect on asphalt modification were researched and contrasted it with SBS modifier. The results show that strong van der Waals forces and chemical covalent bonds are formed between CQDs and SBS polymer chains through a series of physicochemical reactions, resulting in strong interactions. Thus CQDs are uniformly dispersed in the SBS phase to form a homogeneous composite material. With the addition of CQDs, the CQDs/SBS composite modifier with slightly lower molecular weight than SBS modifier and can be better dispersed in asphalt. In addition, CQDs/SBS composite modifier has better thermal stability. Furthermore, CQDs and SBS have a synergistic impact in progressing the high-temperature property of polymer modified asphalt (PMA), which is showed by the improvement in softening point, viscosity, rutting resistance, and elastic recovery rate of CQDs/SBS PMA. However, the low-temperature property of CQDs/SBS PMA decreased, which is manifested by decreased penetration and ductility, increased creep stiffness modulus (S), and decreased the rate of change of stiffness with time (m). Further, CQDs/SBS PMA appears superior better storage stability than SBS PMA. It has the preferences of facile preparation procedure and low cost too, making it a beneficial choice for asphalt modifiers.

Field Performance Evaluation of High Polymer-Modified Asphalt Concrete Overlays

The objective of this paper was to assess the viability of using high polymer (HP) modified asphalt concrete (AC) mixtures in Virginia as a reflective crack mitigation technique or when deemed appropriate as a tool for increased crack resistance on higher volume facilities. This was achieved by compiling and evaluating routine distress survey data against pre-paving distress survey data for relevant in-service HP pavements constructed between 2015 and 2018 and comparing them with several control in-service conventional polymer-modified asphalt (PMA) pavements. This is the first effort in North America to provide a detailed field performance of HP AC mixtures. In general, none of the evaluated mixtures (HP or PMA) was able to prevent reflective cracking completely. The HP sections showed the most promising performance 5 years after construction regardless of traffic level and the pre-existing pavement conditions. The pavement management system data for the reviewed sections indicated a potential controlling effect of the joint condition of the underlying jointed concrete pavement layer regardless of the asphalt mixture type employed (PMA or HP). Moreover, performance evaluations using the network-level pavement management data were conducted to estimate the life expectancy of HP AC overlays. Two different approaches and three levels of analysis were undertaken. Overall, PMA and HP AC overlays had an average predicted service life of 6.2 and 8.3 years, respectively, indicating a 34% extension of performance life of the AC overlays with high polymer modification.

Evaluation of the physical and rheology properties of rubberized asphalt cement

Asphalt cement is a viscoelastic substance that operates like an elastic solid at low service temperatures or under rapid loading. Whenever loaded slowly or at high temperatures, it behaves like a viscous liquid. This classic duality necessitates enhancing the efficiency of an asphalt binder to decrease stress cracking at cold temperatures (fatigue) and plastic deformation at hot temperatures (rutting). The use of polymer-modified asphalt binder is one solution for satisfying today's pavement performance standards. The purpose of this study was to determine the impact of asphalt cement modifiers on the physical and rheological properties of asphalt cement. This study used asphalt cement with a penetration grade of 40-50, modified with styrene-butadiene rubber (SBR) at four different levels of modification, specifically 0%, 2%, 4%, and 6% by weight of asphalt cement. Depending on Rotational viscosity and dynamic shear rheometer, and the traditional test. The mixes modified with SBR polymer showed enhanced physical and rheology characteristics, with decreased penetration and ductility and increased viscosity and softening point, as well as a lower rutting factor, indicating an increase in rutting resistance, according to the experimental data. The performance grade for original asphalt cement was 64-16, and for SBR at 2% additive, the original PG was improved to PG70-16. Adding 4% additive to asphalt cement improved the performance grade to PG76-16, and using 6% increased the performance grade to PG82-16.

Use of waste polyethylene terephthalate (PET) in stone mastic asphalt

Re-use of waste materials Polyethylene Terephthalate (PET) in industrial construction projects such as road pavement can be an effective method of waste management. This study aimed at evaluating the performance of Stone Mastic Asphalt containing 6%, 8%, and 10% waste PET. In this experiment, gravel as coarse aggregate, river sand as fine aggregate, shredded waste PET, and bituminous pitch as binding material were used for making polymer-modified asphalt samples. The study also dealt with the determination of the physical and mechanical properties of the cylindrical samples and compared them with the conventional asphalt samples. The test result shows that the density decreased with the increase in the percentage of waste PET and the maximum 10% addition of waste PET with conventional asphalt resulted in a 3% reduction in density. Percentage water absorption at 0% PET was 2.21% which increased with the increase in the percentage of waste PET and a maximum 10% addition of waste PET resulted in a 13% increase in water absorption. A maximum of 10% addition of PET in the mixture causes 30% reduction in tensile strength. It was identified that the tensile strength ratio (TSR) of the mixtures decreased with the addition of waste PET and Tensile Strength Ratio (TSR) values were above 70% which denoted that all mixes might have enough resistance against damage caused by moisture. However, the usage of waste PET in asphalt could be effective for low-density bituminous pavements and surfaces. So, this method could be the best option for recycling waste PET and thus could contribute to reducing the waste materials from the environment.

Balanced Mix Design Benchmarking of Field-Produced Asphalt Mixtures in Maine, U.S.

Performance testing has been recognized by state highway agencies (SHAs) in the U.S. and the asphalt paving industry as an important tool to complement volumetric properties for improving asphalt pavement performance. Thus, Maine Department of Transportation (MaineDOT) initiated a research effort in 2019 to evaluate the cracking and rutting resistance of asphalt mixtures using several performance tests, including the Hamburg wheel-tracking test (HWTT), indirect tensile cracking test (IDEAL-CT), cyclic fatigue test, and stress sweep rutting (SSR) test. These tests were conducted on reheated common plant-produced asphalt mixtures, and results were analyzed to: (1) develop baseline rutting and cracking performance; (2) evaluate the effects of mixture properties on the performance test results; and (3) verify the performance enhancement from the extended use of polymer-modified asphalt binders. Several mixture properties, such as nominal maximum aggregate size (NMAS), binder performance grade (PG), binder content (Pb), and reclaimed asphalt pavement (RAP) %, were found to have statistically significant effects on the mixture rutting and cracking resistance, especially the HWTT and IDEAL-CT results. Based on the proposed criteria for rutting strain index (RSI) and apparent damage capacity (Sapp), the asphalt mixtures tested would provide satisfactory rutting performance under heavy traffic, and satisfactory cracking performance under standard traffic. In addition, based on the IDEAL-CT benchmarking results, mixtures with polymer-modified binder and/or smaller NMAS were found to have higher cracking tolerance index (CTindex) results. The information from the research effort will help MaineDOT to achieve its goal to move beyond sole use of volumetric properties for asphalt mixture design and acceptance with the implementation of balanced mix design (BMD) for improving the field performance of asphalt pavements.

Laboratory Characterization of Asphalt Binders Modified with Styrene Butadiene Rubber (SBR).

The study describes the laboratory assessment (physical and rheological properties) of the binders (PG 64-22 and PG 76-22) modified with Styrene Butadiene Rubber (SBR), and a comprehensive comparison between these two modified binder types. PG 64-22 and PG 76-22 were used as base binders. Both of the base binders were blended with SBR at four different percentages of content (0%, 4%, 6%, and 8% by the weight of the binder). The base and modified binders were artificially short-term and long-term aged using a rolling thin film oven (RTFO) and pressure aging vessel (PAV) procedures. Superpave binder tests were conducted on the SBR modified binder using rotational viscometer (RV), dynamic shear rheometer (DSR), and bending beam rheometer (BBR). In depth rutting performance was investigated using Multiple Stress Creep Recovery (MSCR). The results of this study indicated that (1) the addition of SBR into both binders increased the viscosity and polymer modified asphalt (PMA) binders observed to have more significant effect on its viscosity property; (2) the higher the SBR content, the better the rutting resistance of the binder and it is observed that the effect is prominent on the control binder; (3) MSCR test results showed that the SBR modified binders improved the binder percentage recovery and found to have a more significant effect on the PG 76-22 binder compared to PG 64-22; and (4) both the control PG 64-22 and PMA PG 76-22 binders resulted in similar trends on the cracking properties and were found to have insignificant effects due to the addition of an SBR modifier.

Mechanical properties of tri-modal epoxy asphalt composites

ABSTRACT Epoxy asphalt composites (EACs) are deemed to be the prior choice for the next generation of long-life pavement material because of their excellent mechanical properties and thermal stability. However, the much higher initial paving costs of EACs than those of traditional thermoplastic polymer-modified asphalts limit their popularisation. To pursue higher-performances-lower-costs EACs, inspired by the ‘multimodal networks’ theory, anhydrides-cured tri-modal rubber-like epoxy asphalt composites (REACs) were conceived and prepared by incorporating reactive styrene butadiene styrene grafted by maleic anhydride (SBS-g-MA), i.e. reactive very long chains (rVLCs), to our previous bi-modal REACs (whose curing agents are composed of two different molecular weights, i.e. short chains and long chains). Their tensile properties and thermo-rheological properties were characterised by means of tensile tester and dynamic shear rheometer (DSR). Results demonstrated that the content of rVLCs has a significant influence on the mechanical properties of the tri-modal EACs. As a result, there is a moderate rVLCs content (1.5 wt.%) based on which the formed tri-modal REACs can achieve higher performance and potentially lower cost for the next generation pavement.

Multi-Level Laboratory Performance Evaluation of Conventional and High Polymer-Modified Asphalt Mixtures

Asphalt concrete (AC) overlays have been one of the most common treatments used by the Virginia Department of Transportation (VDOT) for maintaining/rehabilitating pavements. However, when the overlay is placed on existing composite pavements or cracked AC pavements, differential movements across any cracks or joints can result in physical tearing of the AC overlay. Thus, the long-term performance of many AC overlays will highly depend on their ability to resist cracking. The purpose of this study was to assess the viability of using high polymer-modified (HP) AC mixtures in Virginia as a crack mitigation technique or when deemed appropriate as a tool for increased resistance to rutting and cracking on higher volume facilities. Another objective was to assess the ability of various testing protocols to discern the performance of pavements through a comprehensive evaluation of three conventional polymer-modified (PMA) and five HP field-produced mixtures placed in Virginia. This included laboratory testing at multiple levels of complexity (basic, intermediate, and advanced) on collected asphalt binders, plant-produced asphalt mixtures, and field cores. The performance characteristics of PMA and HP mixes were evaluated in the laboratory in relation to durability and resistance to rutting and cracking. Based on the mixes tested, stone matrix asphalt (SMA) mixes showed better performance than dense-graded surface mixes (SM) regardless of the asphalt binder type. Moreover, HP mixes showed better performance than PMA mixes regardless of the mixture type. Overall, SMA-HP mixes showed the most promising performance among all evaluated mixes.

Using Polyphosphoric Acid and Sulfur to Improve Storage Stability, Aging, and Rheological Properties of High-Density Polyethylene–Modified Asphalt Binder

Abstract One method for reducing the rutting failure of asphalt pavements is to modify the asphalt binder with polyethylene. However, the instability and phase separation between components has always been a major problem in achieving a homogeneous asphalt binder–polyethylene combination. To improve storage stability, one solution is to use crosslinking agents. In this study, the base asphalt binder was modified by using 3 and 7 % high-density polyethylene (HDPE). Subsequently, 1.5 % polyphosphoric acid (PPA) and 0.5 % sulfur were combined with polymer-modified asphalt binder to improve the stability between asphalt binder and polyethylene as well as reduce phase separation. First, the aging component of the prepared asphalt binder samples was evaluated using the attenuated total reflectance Fourier transform infrared spectrometer analysis. Then, the storage stability of asphalt binder samples was investigated by the frequency sweep test. The rutting resistance of asphalt binder samples was determined using the multiple stress creep recovery test, and finally, the fatigue performance of the rolling thin-film oven–aged asphalt binder samples was evaluated using the linear amplitude sweep test. The results revealed that, unlike the sulfur additive that did not have any beneficial effect on the HDPE-asphalt binder, the PPA increased the resistance of rutting, fatigue cracking, aging, and storage stability for the HDPE-asphalt binder.

Materials Approach to Improving Asphalt Pavement Longitudinal Joint Performance

Many states are looking for methods to improve longitudinal joint performance of their asphalt pavements, since these joints often fail before the rest of the surface. With their inherently lower density, longitudinal joints fail by cracking, raveling, and potholing because of the intrusion of air and water. Because of their longitudinal joint issues, and after trying several less-than-successful traditional solutions, Illinois Department of Transportation (IDOT) developed a concept to seal the longitudinal joint region, but from the bottom up. Test sections were constructed in 2001 through 2003 to determine how a newly developed material, called longitudinal joint sealant (LJS), would improve joint performance. LJS is a highly polymer-modified asphalt cement with fillers and is placed at the location of a longitudinal joint before paving. As mix is paved over it, the LJS melts and migrates up into voids in the low-density mix, making the mix impermeable to moisture while sealing the longitudinal joint itself. The IDOT test pavements were evaluated after 12 years and found to have longitudinal joints that exhibited significantly better performance than the control joint sections and were in similar or better condition than the rest of the pavement. Laboratory testing of cores showed decreased permeability and increased crack resistance of mix near joints with LJS as compared with similar mix without LJS. The life extension of the joint area is approximately 3–5 years, and the benefit is calculated to be three to five times the initial cost.

Microwave Induction Heating of Polymer-Modified Asphalt Materials for Self-Healing and Deicing

This study evaluates the influence of polymer-modification on the induction heating capability of asphalt mastic in a microwave field, and investigates how effectively this approach can be utilized for ice melting and self-healing purposes. To this end, different asphalt mastic mixtures with different polymer-modification and mixing procedures were tested under microwave field exposure for induction heating capability, ice-melting ability, and self-healing capacity. The mixtures were made through warm-mix and hot-mix procedures with four bituminous binders, including virgin (unmodified) asphalt and the same binder modified with three types of polymers. The results showed the effectiveness of microwave induction heating of asphalt mastic for both crack-healing and deicing purposes. The binder type was found to influence the ice melting and crack healing rates, such that using a warm-mix asphalt binder resulted in a more efficient heat generation and conduction than using a virgin asphalt binder. While polymer-modification undermined induction-heating, ice-melting, and self-healing performances, SBS-modified asphalt binders exhibited better performance than the other polymer-modified binders.