Performance Intermediate Temperature Research Articles

Performance-based laboratory evaluation of asphaltic mixture containing asphalt binder-Carbon Nano Tube composite

ABSTRACT This research work aimed to evaluate the effect of CNT on the performance of asphaltic mixture. CNT-asphalt binder composite was initially prepared at different CNT dosages (0%, 0.4%, 0.75%, 1.5%, and 2.25% by the weight of asphalt binder). The effect of CNT on the workability of asphaltic mixture was evaluated with the help of compaction data. The change in compaction densification index indicated that such an addition will have a negative impact on the workability of asphaltic mixture. Similarly, the strain response and flow number obtained from the dynamic creep test at 50°C indicated that the addition of CNT will help in improving the rutting performance. Likewise, the variation of Tensile Strength Ratio (TSR) value indicated that the moisture damage resistivity potential of asphaltic mixture can be improved with the addition of CNT. Finally, intermediate temperature performance was evaluated using indirect tensile fatigue and indirect tensile test-based cracking tolerance index. The variation of different parameters from the above approaches indicated that CNT can help in improving the intermediate temperature performance of asphaltic mixture.

Component analysis of bio-asphalt binder using crumb rubber modifier and guayule resin as an innovative asphalt replacer

This research seeks to interpret the component analysis of an innovative bio-asphalt binder using guayule resin at high concentrations and crumb rubber modifier (CRM). Such asphalt modification aims to minimize the dependency on base asphalt and provide new solutions concerning sustainable, flexible pavement industry. Guayule resin is a promising bioresource for asphalt replacement. The provided interpretation could help in understanding the asphalt-rubber-guayule interaction mechanism. Fourier transform infrared spectroscopy (FTIR), supported by thermo-gravimetric analysis (TGA), was used to investigate the component analyses of guayule resin composition, asphalt-guayule interaction, and asphalt-rubber-guayule interaction, followed by oxidative aging behavior. Additionally, the rheological properties at high and intermediate temperatures were provided to link the microscale properties with the final product performance. The study clarified the distinct carbon and hydrogen compositional elements of guayule resin. Asphalt and guayule resin had similarities in component composition and rheological behavior with temperature susceptibility. Asphalt-guayule interaction yielded a physical blending, with no chemical reaction. Rubber seems to dissolve in both asphalt-rubber and asphalt-rubber-guayule interactions evenly. Devulcanization occurred, resulting in a partial migration of CRM polymeric components to the liquid binder. This was reflected in the enhanced performance of asphalt-rubber-guayule blends at high temperatures. However, due to the strong oxidation bonding chains attributed to guayule resin, the oxidative aging negatively affected the guayule-based binder performance reflected on the intermediate temperature performance. The mix performance was initiated with the guayule-based binder's successful performance against rutting susceptibility, comparative to the base asphalt.

Investigation of the performance properties of asphalt binders and mixtures modified by Crumb Rubber and Gilsonite

The mechanical performance properties of asphalt binders and mixtures can be enhanced by utilizing several modifiers, including Crumb Rubber (CR) and gilsonite. The current study evaluated the effects of CR and gilsonite additive on the rheological behavior of gilsonite and CR/gilsonite composite modified binders and Stone Matrix Asphalt (SMA) mixtures. In this research, to modify original binder, gilsonite (0%, 10%, 20%, 30% and 40% by weight of binder), and CR (5%, 10%, 15%, and 20% by weight of binder) were used. The modified binders were subjected to rotational viscosity (RV), dynamic shear rheometer (DSR), multiple stress creep recovery (MSCR), and linear amplitude sweep (LAS) tests. Also, the gilsonite and CR/gilsonite modified mixtures were subjected to four-point beam fatigue (FPBF), resilient modulus (Mr), indirect tensile strength (ITS), dynamic creep, and wheel track tests. The results revealed that the utilization of gilsonite reduced the low temperature cracking resistance of binders while adding CR to gilsonite modified binders, the low-temperature cracking of modified binders enhances. According to the results, utilization of gilsonite causes a decrease in the resistance of binders against fatigue cracking, while adding CR to gilsonite modified binders, the fatigue life of binders increases. Results revealed that both gilsonite and CR enhance the elasticity and recovery properties of binders, and consequently, the strength of binders versus permanent deformation improves. Mixture test results revealed that using gilsonite and CR increases the Mr, permanent deformation resistance, tensile strength, fracture energy, and intermediate temperature performance of specimens. It can be concluded from the results that CR has a positive impact on enhancing the gilsonite modified binders and mixtures performance.

Effects of anti-striping agents on performance of binder and stone matrix asphalt (SMA) mixtures containing polyphosphoric acid/styrene-butadiene rubber composite polymer blends and warm mixture additives

This work evaluated the effect of Anti-Stripping Agents (ASAs) on performance behavior of bitumen and high and intermediate temperature performance of SMA mixtures modified by Poly Phosphoric Acid (PPA), Warm Mix Asphalt (WMA) and Styrene-Butadiene Rubber (SBR) additive. Through this paper, the AC-60/70 and AC-85/100 penetration grade bitumens were used as base bitumen. Moreover, three liquid ASAs (ASA (1), ASA (2), ASA (3)), PPA (1% by weight of bitumen), SBR (2% by weight of binder), and two types of warm mix additives (3% Sasobit and 0.3% Zycotherm) were used as a mixture modifier. For evaluating the performance behavior of bitumen, the rotational viscosity, Dynamic Shear Rheometer, and Bending Beam Rheometer, Multiple Stress Creep Recovery (MSCR), and linear Amplitude Sweep (LAS) tests were implemented. Moreover, Resilient Modulus (Mr), Indirect Tensile Strength (ITS), dynamic creep, wheel track, and Four-Point Beam Fatigue (FPB) tests were performed to investigate the performance of mixture samples. Based on the outcomes of the MSCR test, the utilization of SBR/PPA additive and ASAs decreased the Jnr value. Among modified binders, the binders modified by ASA (2) have the lowest Jnr value followed by binders modified by ASA (1) and ASA (3). According to the outcomes of LAS test, the utilization of ASAs leads to increase in the fatigue life of the original binder. According to the outcomes, the utilization of WMA additives and ASAs caused the Mr, ITS, rutting resistance, and fatigue life to increase. Among ASAs, the ASA (2) has the greatest influence on enhancing the performance of mixtures. Based on results, Sasobit additive has a better effect than Zycotherm on enhancing the properties of samples.

Feasibility of using Mastic for Performance Grading in Place of Extraction using SPS10 Mixtures

Because of the increased use of reclaimed asphalt pavement, reclaimed asphalt shingles, rejuvenators, and other additives, performance of asphalt mixtures can no longer be guaranteed by controlling properties of the binder. To determine the effect of additives on asphalt performance, the current procedure is to extract the binder from the mixture using solvents and recover the binder by removing the solvent. This is a two-step procedure, which can be time consuming and costly and which requires chemicals considered hazardous unless used with special care. Another issue is the quality of the extracted binder, as the process of dissolving the binder and recovering it from chemicals may affect the properties of the extracted binder. In this study, we suggest the use of mastic separated from the mixture, in place of extraction. The fine portion of the mixture (particles less than 0.25 mm) is physically separated from the mixture without use of solvents. This material is called composite mastic since it includes effects from all additives on the binder. The process of preparing composite mastic is significantly faster and less costly than extracting the binder. The separated mastic is tested following the Unified Performance Tests by incremental Method (UPTiM) using a dynamic shear rheometer to determine the high-, low-, and intermediate-temperature performance grades, similar to those of asphalt binder. This study shows strong correlations between properties of composite mastic, extracted asphalt, and asphalt mixture. Therefore, testing mastic could be a reliable alternative to testing extracted binder and compacted mixture.

Effect of Recycled Asphalt Pavement Binder on Rheology of Crumb Rubber–Modified Binder—An Experimental, Analytical, and Analogical Study

Abstract The popularity of recycled asphalt pavement (RAP) is on the rise because of the benefits of sustainability. In an unavoidable scenario wherein crumb rubber–modified binder (CRMB) is adopted as a base binder in RAP mixes, the binder from RAP will blend with CRMB, thereby influencing its rheology and performance at high, intermediate, and low temperature. Hence, in this study, binder extracted from two RAP sources (RAP X and RAP Y) was blended with CRMB at varying proportions of 15, 25, and 40 % by weight. Isochronal temperature sweeps, isothermal frequency sweeps, and bending beam rheometer tests were conducted on the prepared blends. Thereafter, analytical and analogical studies were performed using master curve construction, 2S2P1D, and Huet modelling. The results indicated that RAP from different sources affects the high-, intermediate-, and low-temperature performance of CRMB. Different RAPs were observed to have contrasting effects on high-temperature performance grading. Intermediate-temperature performance based on cross-over temperature (TCROSS-OVER) indicated a compromise because of the inclusion of RAPs. An evaluation of the differences among critical temperatures at low temperature (ΔTc) indicated the degradation of low-temperature performance. Such changes in high-, intermediate-, and low-temperature performances were validated by complex modulus (G*), stiffness (S(t)), and stress relaxation (E(t)) master curves. Finally, the 2S2P1D and Huet model were observed to depict reasonably good fits for the prepared blends. This study concludes that RAPs from different sources have contrasting impact on CRMB and may adversely impact the intermediate- and low-temperature performance.

Investigating the effects of nano Al2O3 on high and intermediate temperature performance properties of asphalt binder

The present study explores the use of nano Al2O3 as a potential asphalt binder modifier. The study investigates the effects of different concentrations (0%,0.5%,1% and 2% by weight of the asphalt binder) of nano Al2O3 on various properties of the asphalt binders. XRD analysis is used to study the amorphous/crystalline nature of the base asphalt binder and nano Al2O3 modified asphalt binder. The influence of different temperatures and strain rates on the viscosity of the asphalt binder is evaluated. It was seen that the asphalt binder showed a shift from Newtonian behaviour to non-Newtonian behaviour upon the addition of nano Al2O3. The rutting evaluation of the asphalt binders was carried out by utilising different approaches like Superpave rutting parameter, multiple stress creep and recovery test, zero shear viscosity, and creep test. Furthermore, intermediate-temperature performance and aging resistivity of the modified asphalt binders was also evaluated. Results showed that the addition of nano Al2O3 enhances the stiffness of the asphalt binder and improves its recovery abilities. The modified asphalt binder was found to perform well under varying stresses and sustained loading and hence showed improved permanent deformation characteristics. Fatigue performance was evaluated utilising Superpave fatigue parameter and time sweep tests, and the nano Al2O3 modified asphalt binders showed improved fatigue life. The addition of nano Al2O3 also leads to an improvement in the aging resistance of the asphalt binder. The study shows an overall improvement in high temperature, intermediate temperature, and aging resistance of the asphalt binders using nano Al2O3 as an asphalt binder modifier.

Investigating the Influence of Replacing Two Biomass Ashes with Conventional Filler on High and Intermediate Temperature Performance of Mastic and Mixture

Abstract The aim of this research was to evaluate the rheological properties of mastics and performance of mixtures consisting of two biomass ashes named as coal waste ash (CWA) and rice husk ash (RHA) used as a replacement of limestone filler at different concentrations. The high and intermediate temperature behavior of binders was evaluated through multiple stress creep recovery (MSCR) and linear amplitude sweep (LAS) tests. Moreover, Marshall stability, resilient modulus, dynamic creep, moisture susceptibility, wheel track, indirect tensile strength, and four-point beam fatigue tests were implemented to investigate the mechanical performance of mixtures. Based on MSCR test results utilization of RHA led to improve the rutting resistance of binders, while CWA decreases the rutting resistance of binders. LAS test results indicated that addition of RHA to original binder increase the fatigue life of binder, while CWA decreases the fatigue behavior of mastics. Based on the results, the addition of styrene-butadiene-styrene (SBS) increases the fatigue life of mastics. Results revealed that the addition of RHA improves the Marshall stability, resilient modulus, rutting properties, moisture resistance, and tensile strength of asphalt mixtures, while CWA has negative impact. In general, the obtained results from this study indicated that reuse of RHA and CWA waste materials in the northern part of Iran, where there are lots of RHA and CWA materials, especially RHA, in pavement engineering, has two main effects. First, environmental problems are reduced. Second, the performance properties of mixtures are enhanced.

High-Temperature Performance of Recycled Low-Density Polyethylene-Modified Asphalt Binder Reinforced with Thermally Treated Polyacrylonitrile Fiber

Global shift toward green construction has resulted in an increased focus on the use of recycled plastic waste for asphalt binder modification. However, there are some performance issues still associated with the recycled plastic-modified binder. In this study, the viscoelastic behavior of recycled low-density polyethylene (LDPE)-modified asphalt binder reinforced with thermally treated polyacrylonitrile (PAN) fiber was investigated. The duration of the fiber thermal treatment was optimized at 220 °C, based on asphalt viscoelastic performance, SEM image analysis of fiber surface morphology, and fiber molecular structural change via X-ray diffraction technique. Two sets of PAN fiber-reinforced LDPE asphalts were studied: the thermally treated fiber-reinforced LDPE-modified asphalt and untreated fiber-reinforced LDPE-modified binders. Enhanced and exposed fiber surface, in addition to a molecular structural shift toward aromatic form, improves compatibility between the thermally treated PAN fiber and the base asphalt binder. This results in an improved high- and intermediate-temperature performance of the LDPE-modified asphalt binder reinforced with thermally treated fiber, relative to the LDPE-modified asphalt reinforced with untreated fiber.

Effect of recycled asphalt binder on high and intermediate temperature performance of polymer modified asphalt binder

The present study aimed at investigating the effect of Recycled Asphalt Pavement (RAP) binder on high and intermediate temperature performance of Polymer Modified Binders (PMB) through advance laboratory characterization techniques. Different RAP binder proportions (0%, 15%, 25% and 40% by the weight of PMB) were initially blended with PMB. Different characterization techniques such as Superpave rutting parameter (G*/Sinδ), Shenoy parameter, Multiple Stress Creep Recovery (MSCR) and Zero Shear Viscosity (ZSV) tests were used for evaluating high temperature performance. Based on the different rheological parameters, improvement in rutting performance was observed with the addition of RAP binder. Likewise, intermediate temperature performance was evaluated using Linear Amplitude Sweep (LAS), Double Edge Notch Tension (DENT) and Elastic Recovery (ER) test. The improvement in high temperature performance and degradation in intermediate temperature performance shows that care must be taken while selecting the appropriate amount of RAP based on prevalent failure type in the field.

Use of nanomaterial for asphalt binder and mixtures: a comprehensive review on development, prospect, and challenges

This article aimed at providing comprehensive information on the use of nanomaterial in asphalt binder and mixes based on an exhaustive review of the literature. The complete literature review can broadly be perceived into three different segments. The first segment of this review discusses (a) the need of nanomaterial, and (b) different types of nanomaterials with their respective characteristics. The second segment of this review work discusses about the various functional aspects which have been reported to have an important role on or before construction of asphaltic layer, i.e. (a) mixing of nanomaterials with asphalt binder, (b) nanomaterial dispersion into asphalt binder matrix, and (c) high-temperature storage stability of binary composite (asphalt binder and nanomaterial) and triple composite (asphalt binder, polymer additive and nanomaterial) under high-temperature condition. Among different types of mixing approach, use of a high shear mixer and ultra-sonication individually or in combination has been reported in the literature for an efficient way for dispersion of nanomaterial in an asphalt binder matrix. To evaluate mixing of nanomaterial in asphalt binder matrix, different microscopic approach such as X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM) has been recommended in the literature. The third segment emphasises on the effect of nanomaterial addition on performance-based parameters for (a) aging resistivity potential, (b) moisture damage resistivity potential, (c) intermediate, (d) high, and (e) low-temperature performance. The review of the literature showed that the addition of nanomaterial to asphalt binder not only improves the aging resistivity potential of asphalt binder but also improves the moisture damage resistivity potential, high, and intermediate temperature performance of asphalt binder and mixes. However, the mixed response was observed from the review of literature for the corresponding effect of nanomaterial on low-temperature performance parameters.

Efecto de los polímeros sobre las propiedades reológicas de los betunes céreos

The definition of bitumen wax has been formulated to facilitate the distinction between harmful wax and less harmful or non-harmful. Since exact behaviour of waxes within bitumens is not completely determined and the absence of cooperative study related to modification of bitumens involving different amounts of waxes, the values found in the study are thought to be useful in determining which content of wax and type of polymer would be better for the needs of petroleum refineries in different countries. The scope of this study is to minimize the negative effects of waxes within bitumens obtained from different sources. For this purpose, modified bitumen samples were prepared by using different types of polymers such as elastomers, plastomers and polyethylene groups. Following the determination of the contents of wax by Differential Scanning Calorimetry and TS EN 12606-1, rheological properties of waxy bitumens and polymer modified bitumens (PMB) were evaluated using dynamic shear rheometer tests. The intermediate temperature performance levels of PMB were also determined by fatigue parameters. Besides, rutting performance of PMB was evaluated using Zero Shear Viscosity and Multiple Stress Creep Recovery tests.

Evaluation of intermediate temperature cracking performance of warm mix additive modified asphalt binders

In the present study, intermediate temperature cracking performance of different types of asphalt binders containing warm mix asphalt (WMA) additives was evaluated using three test methods namely, Superpave fatigue parameter, linear amplitude sweep (LAS) and double edge notch test (DENT). The Superpave fatigue, LAS, and DENT tests are based on dissipated energy, viscoelastic continuum damage (VECD) and work of fracture approaches, respectively, and thus each of the tests may result into different performance ranking of asphalt binders. The outcome of the Superpave fatigue, LAS and DENT tests are G∗sinδ, number of cycles to fatigue failure (Nf), and critical tip opening displacement (CTOD) based on which cracking potential of asphalt binder can be assessed. An asphalt binder having a low Superpave parameter, high Nf and high CTOD values are expected to have better intermediate temperatures cracking performance. The present study selected three control binders namely virgin (AC), styrene-butadienestyrene (SBS) and crumb rubber modified (CRM) binders were modified using three WMA additives namely Fischer-tropsch (FT) wax based, chemical surfactant (CS) based and water based (WB). Control binders were modified with 2%, 6% and 2% (by weight of asphalt binder) of FT, WB and CS, respectively, using a mixer. The results showed that, based on G∗sinδ and CTOD parameters, CS modification reduced stiffness (reduced G∗sinδ) and improved ductile performance (increased CTOD) of control binders. However, WB and FT modification increased stiffness and degraded the ductile performance of control binders, except for SBS with 6%WB binder which showed higher CTOD than control SBS binder. On the other hand, considering performance based on Nf parameter, WMA additive modification improved fatigue life of control binders, except for SBS with 2%CS binder which showed lower Nf as compared to control SBS binder. Control binders with and without WMA additives were ranked based on G∗sinδ, Nf and CTOD parameters. AC and CRM binder with and without WMA additives followed similar performance ranking based on G∗sinδ and CTOD parameters. It is difficult to conclude over the best suitability of intermediate temperature performance parameter as mentioned tests involve different loading conditions and analysis approaches. Hence, further investigation on asphalt mixes is necessary to identify the best suited intermediate temperature performance parameter of asphalt binders, and its possible correlation with mix performance.

Improving intermediate temperature performance of Ni-YSZ cermet anodes for solid oxide fuel cells by liquid infiltration of nickel nanoparticles

Liquid infiltration of NiO followed by reduction to form Ni nanoparticle catalysts in solid oxide fuel cell (SOFC) can produce a high density of electrochemical reaction sites. In recent years, electrode architectures utilizing porous oxide substrates with ionic conductivity or mixed ionic-electronic conductivity and connected networks of nickel produced by liquid infiltration have become a popular approach to improve SOFC anode catalytic performance, especially for operating temperatures less than 800 °C. However, infiltrated nickel structures suffer from poor durability, demonstrating significant loss in performance during the first 100 h of use. In contrast, traditional Ni-yttria stabilized zirconia (Ni-YSZ) cermet SOFC anodes exhibit long-term performance stability. However, Ni-YSZ cermet anodes have micron sized structures, and consequently have a significantly lower density of electrochemical reaction site density than infiltrated nickel structures, which have dimensions of around 100 nm. In this study, the performance impact of liquid phase infiltration of nickel nanoparticles into Ni-YSZ cermet anode supported SOFCs is studied by measuring the electrochemical behavior of infiltrated cells at 800 °C, 700 °C, and 600 °C, and comparing them to the performance of an uninfiltrated cell. Durability of the nanoparticles after electrochemical testing is also assessed using a method for quantifying particle statistics from fracture cross sections.

Laboratory performance of Recycled Asphalt Mixes containing wax and chemical based Warm Mix Additives using Semi Circular Bending and Tensile Strength Ratio tests

Durability and sustainability are two major requirements of the asphaltic pavement structure. Durability aspect may involve performance parameters such as fracture property, moisture sensitivity etc., whereas, sustainability aspect may involve utilization of Recycled Asphalt Pavement (RAP) and Warm Mix Additive (WMA) in the conventional asphaltic mixture. Though improvement in high temperature performance may be expected with the addition of RAP due to its stiffer nature, it may degrade intermediate temperature performance. Additionally, RAP utilization may also increase the mixing and compaction temperature during the construction phase. Therefore, researchers have recommended using different WMA additives to decrease production temperature of mixes containing RAP. Though the use of WMA additives with RAP may decrease mixing and compaction temperature, their effects on various performance parameters of the asphaltic mixture must be evaluated. Sufficient research works have been reported on the performance of RAP and WMA mixes at high temperature, however, so far, limited work is available on understanding effects of RAP and WMA additives on fatigue and moisture sensitivity of asphalt mixture. Therefore, the present research work aimed at evaluating intermediate temperature fracture properties and moisture sensitivity of asphaltic mixture containing RAP and WMA. Five different RAP contents (0%, 10%, 20%, 30%, and 40%), two different types of WMA additives (2% wax based “Sasobit” and 0.5% chemical based “Evotherm”) and one without WMA additive (Control mixture) were considered. Fracture properties of different asphaltic mixture combinations were evaluated using Semi Circular Bending (SCB) test. Improvement in fracture property of Control mixture was observed with increase in RAP content, however, the addition of wax based and chemical based WMA additives showed an overall reduction in fractured resistance. Further, the asphaltic mixture containing wax based WMA additive showed better fracture performance compared to the corresponding mixture containing chemical based WMA additive. Similarly, moisture sensitivity of asphaltic mixtures was evaluated using Tensile Strength Ratio (TSR) approach. Addition of both WMA additives resulted in lowered Indirect Tensile Strength (ITS) under dry as well as wet condition. Though the addition of WMA additive showed a negative impact on moisture sensitivity, all mixture considered in the present research work passed the minimum TSR requirement. Therefore, wax and chemical based WMA additive may deem acceptable from moisture sensitivity point of view.

High- and Intermediate-Temperature Performance of Asphalt Binder Containing Carbon Nanotube Using Different Rheological Approaches

AbstractThe present research work was undertaken to evaluate the rutting performance of carbon nanotube (CNT)–modified asphalt binders. Additionally, intermediate-temperature performance, aging res...

Mechanism of low- and intermediate-temperature performance improvement of reclaimed oil-modified asphalt

To better understand oil modifiers’ effects on the performance of asphalt binders at low and intermediate temperatures and the mechanisms of the modification, laboratory tests including mechanical property tests and microscopy tests are performed. It is found that oil modifiers can improve the performance of asphalt binders at low and intermediate temperatures significantly. By comparing the absorption peaks of oil modifiers, neat binder and oil-modified asphalt, it is found that the oil modification of asphalt is mainly by physical modification. In addition, a new partition method using gel permeation chromatography spectrum is recommended to investigate the modification mechanism of oil-modified asphalts. With this new method, it is found that the large molecular size (LMS) content correlates well with low-temperature performance; parameter B calculated from fatigue equation correlates well with the content of medium molecular size (MMS), and fatigue life also has a relatively good relationship with LMS. Overall, it is shown that oil modifiers improve the performance of binders at low and intermediate temperatures by decreasing the LMS and MMS of contents.

Investigation of rutting, fracture and thermal cracking behavior of asphalt mastic containing basalt and hydrated lime fillers

The present study was undertaken to evaluate rutting, fracture and thermal cracking resistance behavior of asphalt mastic containing inert and active fillers. A control neat binder (AC-30) along with basalt (B) as an inert filler and hydrated lime (HL) as active filler were selected in this study. The asphalt mastics were prepared for different percentages of HL (5, 10, 15 and 20%) filler, in such a way that Filler to Binder (F/B) ratio becomes 0.8. A total of five combinations of asphalt mastic were prepared such as: AC-30+80% B+0% HL, AC-30+75% B+5%HL, AC-30+70% B+10%HL, AC-30+65% B+15%HL, and AC-30+60% B+20%HL. The rutting, fracture and thermal cracking resistance of asphalt mastics was evaluated using Superpave rutting factor parameter, Double Edge Notched Tension (DENT) and Bending Beam Rheometer (BBR), respectively. Influence of HL on the performance of neat asphalt mastic was observed to be predominant in high-temperature range as obtained from the G∗/Sinδ value. The aging resistivity of asphalt mastic increased with the inclusion of HL, indicating a better rutting performance of asphalt mastic. The intermediate-temperature performance of asphalt mastic with HL was found to be higher compared to neat asphalt mastic from Critical Tip Opening Displacement (CTOD) results, implying better resistance to fracture. The addition of HL increased the low-temperature performance of asphalt mastic obtained from S(t) and m(t) values with S(t) and E(t) master curve, indicating enhanced resistance to thermal cracking. The combined effect of B and HL filler on the G∗/Sinδ, CTOD, S(t), m(t) and E(t) parameters are presented in this study. In addition, ranking of asphalt mastics based on various parameters (i.e. CTOD and m(t)) is discussed in this paper.

High and intermediate temperature performance evaluation of crumb rubber modified binders with RAP

Abstract The present study was undertaken to evaluate high and intermediate temperature performance of a crumb rubber modified binder (CRMB60) blended with different percentages (i.e., 0%, 15%, 25% and 40%) of binder extracted from reclaimed asphalt pavement (RAP). The Brookfield viscosity, Superpave high performance grade (PG), and complex modulus were measured for CRMB60 blended with RAP. The rutting and fatigue resistances of CRMB60 with and without RAP were evaluated using multiple stress creep and recovery (MSCR) and linear amplitude sweep (LAS) tests, respectively. The results showed that addition of RAP improves temperature susceptibility of CRMB60. The Superpave high PG of CRMB60 binder bumped by one PG interval (i.e., PG88–PG94) with addition of 15% and 25%RAP. However, further increase in RAP (40%RAP) did not alter PG, which is contrary to what have been reported in literature. The MSCR test showed that non-recoverable creep compliance ( J nr ) of CRMB60 decreased with an addition of RAP up to 25%, indicating the improved rutting resistance of CRMB60. However, J nr of CRMB60 increased with addition of higher percentage of RAP (i.e., 40%), showing poor rutting resistance compared to control CRMB60. The LAS test showed that fatigue damage resistance of CRMB60 with 15% and 25% RAP was less compared to control CRMB60. Overall the present work showed the addition of RAP increased rutting resistance, however, deteriorated fatigue performance of CRMB60. The higher percentage of RAP showed a different trend than expected, which might be due to reduced concentration of rubber particles or depolymerization of rubber particles after addition of high content of RAP.

Communication—Improving Intermediate-Temperature Performance of a Screen-Printed LSCF Cathode with Infiltrated LSCF Nanoparticles

The present study investigates the mass loading effect of an infiltrated La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) nanoparticles (NPs) catalyst on the area-specific polarization resistance (Rp) of a screen-printed porous LSCF cathode for solid oxide fuel cells. The results show that Rp of the LSCF-NPs decorated LSCF cathode can be substantially reduced by as much as 89.3% after a single-step impregnation of 1.5 M nitrate solution containing La:Sr:Co:Fe = 0.6:0.4:0.2:0.8 with a mass loading of 3 wt%.