Ductility Test Research Articles

Assessing the effectiveness of bio-based oil in rejuvenating aged asphalt: a comprehensive physical, rheological, chemical, and mechanical examination

The utilization of reclaimed asphalt pavement (RAP) in flexible pavement construction and rehabilitation has gained significant traction, driven by the need to conserve limited natural resources. This study explores the effectiveness of bio-based oils derived from harvested crops as rejuvenators in asphalt mixtures containing 50% RAP. Comprehensive assessments were conducted, including penetration, softening point, viscosity and ductility tests, to determine the optimal rejuvenator dosage. Additionally, evaluations of rolling thin film oven (RTFO) aging, retained penetration and ductility, equivalent softening and breaking points, plasticity temperature range, stiffness modulus, complex modulus, and phase angle were performed. Fourier-transform infrared (FTIR) spectroscopy, Marshall immersion, and moisture susceptibility tests further validated the rejuvenator's efficacy in improving asphalt properties. The incorporation of 1.8% bio-oil significantly reduced the viscosity of the mixtures, enhancing workability. The rejuvenator effectively compensated for the loss of light components in aged binders, restoring the maximum and minimum temperature performance to levels comparable to virgin asphalt (VA). Mechanical testing revealed that bio-oil mitigated the aging effects of RAP asphalt, and the rejuvenated mixtures showed considerable improvements over both VA and non-rejuvenated RAP mixtures, where the rejuvenated specimens achieved 90.8 and 89.4% of retained strength index (RSI) values for 24- and 48-h immersion periods, respectively comparing with 88.9 and 86% post-immersion of VA for similar durations. These findings underscore the potential of bio-oil as a sustainable and eco-friendly solution for rejuvenating aged asphalts, paving the way for more sustainable asphalt production practices.

A comparative study into the effect of spent coffee powder and ash on improving the mechanical properties of bitumen

Nowadays, waste and renewable materials are used to modify bitumen and asphalt, reduce costs, decrease the use of natural resources, and maintain ecological balance, and have thus received much attention. This study aimed to improve the rheological properties of bitumen and reduce spent coffee grounds' (SCG) waste by partially replacing it with SCG powder and ash. SCG powder and ash were added in percentages of 0, 1, 3, 5, and 8 wt percent of bitumen to check the properties of control and modified bitumens. Microstructural properties were evaluated by Fourier transform infrared spectroscopy, thermal gravimetric analysis, X-ray fluorescence spectroscopy (XRF), and scanning electron microscopy (SEM). Penetration, softening point, and ductility tests were performed to check the physical properties of bitumens, along with the storage stability test. Rheological tests (viscosity, bending beam rheometer (BBR), dynamic shear rheometer (DSR), multiple stress creep and recovery (MSCR), and linear amplitude sweep (LAS) were also carried out. According to the BBR results, adding SCG powder up to −12 °C and adding SCG ash up to −6 °C increased the resistance to low temperatures. Based on DSR and MSCR results, SCG, either in the form of ash or powder, increased the resistance to rutting, and adding SCG ash improved the high temperature performance of bitumen by 1 grade. At 64 °C, adding 8 % of SCG powder increased the rutting resistance by 43 %, and adding SCG ash raised the rutting resistance by about 113 %. LAS results also showed that SCG ash outperforms SCG powder in fatigue. Although both SCG powder and ash performed well in high, moderate, and low temperatures, SCG powder performed better in cold regions, and SCG ash performed better in regions with temperate and tropical climates.

Effect of high-density-polyethylene (HDPE) and waste tire rubber (WTR) on laboratory performance of styrene butadiene styrene (SBS) modified asphalt

To reduce the cost of SBS modified asphalt, we incorporated waste high-density polyethylene (HDPE) and waste tire rubber (WTR) as partial substitutes for SBS modifier. The performance parameters for HDPE, WTR, and SBS synergistic modified asphalt were designed using the response surface method. Specifically, modified asphalt groups with excellent conventional properties were identified through penetration, softening point, and ductility tests. The high/low-temperature rheological properties and anti-aging properties of the selected modified asphalt were investigated. The modification mechanism of the composite modified asphalt was studied using fluorescence microscopy (FM). Subsequently, a cost analysis of the modified asphalt was conducted. Based on the aforementioned studies, we recommend a composition of 1.5% SBS, 3% HDPE, and 10% WTR, which demonstrated superior performance compared to 4% SBS modified asphalt. Furthermore, the cost of the modified asphalt was found to be 13.3% lower than that of SBS modified asphalt.

Impact of antiaging additives on the conventional properties of bituminous binder

Aging of binders is a complex phenomenon which reduces the longevity of flexible pavements. Aging involves change in physical, chemical, and morphological properties of binder which makes the binder brittle and highly susceptible to fatigue and thermal cracking. Antiaging additives enhance the service life of flexible pavements by reducing the impact of aging on the performance of binders. An iterative approach is essential to identify the optimal dosage of antiaging additive necessary to counteract the aging effects on binder. The present study aims to evaluate the mixing conditions for uniform dispersion of carbon black and hydrated lime within the binder matrix and thereby evaluate the impact of incorporating these antiaging additives on the conventional properties of binder. For this purpose, varying proportions of carbon black and hydrated lime are added to VG 30 binder and is subjected to softening point, ductility, and penetration tests. The optimal dosage of carbon black and hydrated lime is found to be 6 and 12% respectively based on their significant effects on the conventional properties of the binder. An optimal mixing duration of 60 and 75 min ensures uniform dispersion of carbon black and hydrated lime within the binder matrix at a mixing temperature of 120 °C and a speed of 1000 rpm thereby producing a homogenous binder mastic. Incorporation of antiaging additives up to the optimal dosage enhances the softening point whereas decreases the penetration and ductility of binder. The increase in softening point of binder with incorporation of carbon black and hydrated lime signifies enhanced resistance to rutting and permanent deformation of binder, whereas the reduction in ductility and penetration of binder with incorporation of carbon black and hydrated lime signifies the reduced susceptibility of binder to environmental factors such as temperature fluctuations, UV radiation, and oxidation. The surface texture of the additive influences the ability of binder adsorption, which subsequently affects the rheological properties of binder mastics. Significant improvement in conventional properties of binder with incorporation of carbon black and hydrated lime paves a viable and cost-effective solution for engineering application as it has a subsequent effect on the rheological properties of binder.

Effect of nano-modified EVA on the physical and rheological characteristics of SBR modified asphalt binder

The effects of nanoclay-modified ethylene-vinyl acetate (MEVA) on the physical and rheological properties of styrene–butadiene–rubber (SBR)-modified asphalt binder were investigated. MEVA/SBR composite-modified asphalt binders (MESBR) were prepared with 4 % SBR and varying MEVA content. The effect of MEVA on the properties of SBR-modified asphalt binder (SBRMA) was investigated through penetration, softening point, ductility, viscosity, temperature sweep, and frequency sweep tests. Furthermore, multiple stress creep recovery and bending beam rheometer tests were performed to analyse the deformation resistance and low-temperature performance of MESBR. Additionally, the storage stability of MESBR was evaluated through separation tests and fluorescence microscopy. The results indicated that MEVA addition significantly enhanced the physical and rheological properties of SBRMA both before and after ageing. Compared with SBRMA, MESBR exhibited improved deformation and ageing resistance, making it suitable for use under standard traffic loads at temperatures up to 76℃. However, MEVA exhibited a slightly negative impact on the low-temperature performance and storage stability of MESBR. With the addition of 5 % MEVA, MESBR exhibited favourable comprehensive performance and good storage stability.

Characterization of 30/45 asphalt binder modified with kraft lignin in relation to short-term aging

In this study, the addition of lignin granules to the asphalt binder PAC 30/45 and its effects on short-term aging were investigated. Penetration, softening point, and ductility tests were conducted before and after RTFOT (Rolling Thin Film Oven Test). Laboratory results revealed that incorporating lignin into the asphalt binder significantly improved aging resistance compared to the pure binder. This was evidenced by reduced penetration, increased consistency, higher softening point, and satisfactory ductility after aging. Lignin also decreased the binder's sensitivity to temperature variation, indicated by a Thermal Susceptibility Index (TSI) closer to zero. While improvements were not as pronounced as in previous studies with PAC 50/70, adding 3% lignin showed benefits compared to the unmodified binder, whereas 6% lignin made PAC 30/45 more susceptible to oxidation. It is concluded that lignin can enhance the rheological properties of PAC 30/45, increasing its stiffness, durability, and aging resistance. Further exploration of lignin concentrations below 3% and above 6% is recommended to better understand oxidative effects on the 30/45 binder and confirm the benefits of minor additions.

Characterisation Techniques for Bituminous Binder

Bituminous binders, often referred to as asphalt, play a pivotal role in the construction and maintenance of flexible pavements. As the demand for durable and sustainable infrastructure continues to rise, a thorough understanding of the physical and rheological properties of bituminous binders becomes imperative. This manuscript presents a comprehensive review of various mechanical tests used to assess bituminous binder properties, including penetration (Pen), softening point (SP), penetration ratio (PR), penetration index (PI), ductility tests and absolute and kinematic viscosities. These mechanical tests serve as fundamental tools for evaluating binder consistency, hardness, ductility and flow behaviour. SP and Pen measurements are employed to grade bituminous binders based on their response to temperature. Additionally, PR and PI provide valuable insights into binder performance under varying environmental conditions. Ductility tests offer critical information about a binder’s ability to elongate without breaking, a crucial factor in withstanding the stresses imposed by traffic. In parallel, the manuscript underscores the significance of understanding the rheological properties of bituminous binders. Dynamic shear rheometry (DSR) is introduced as a method for characterising complex modulus (G*), fail temperature and phase angle (δ) behaviour under different temperature and loading conditions. These tests are well established in the USA based on Strategic Highway Research Program (SHRP) specifications. Their relevance in the Indian context is discussed, with recent inclusion of rheological parameters in the Bureau of Indian Standards (BIS) specification. The manuscript highlights the role of instrumental analysis techniques, including Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) and scanning electron microscopy (SEM), in uncovering the molecular and microstructural aspects of bituminous binders. FTIR aids in identifying functional groups within the binder, elucidating chemical composition and aging effects, while NMR provides insights into molecular mobility and heterogeneity. SEM is instrumental in revealing the binder’s microstructure and its interaction with aggregates. In conclusion, this manuscript offers a comprehensive analysis of both mechanical and rheological testing, emphasising their significance in evaluating bituminous binder properties. It also stresses the growing importance of instrumental analysis techniques, particularly for chemically modified bitumen. The primary aim is to provide a valuable resource for researchers, engineers and practitioners in the field of civil engineering and infrastructure development.

The Effect of the Temperature–Humidity Coupling Cycle on the Performance of Styrene Butadiene Styrene Polymer-Modified Asphalt Mastic

To study the variation laws and effects of asphalt mastic under the cooperative interaction of different temperatures and humidities, cyclic conditions for different temperature ranges were set to conduct indoor experimental simulations of thermal–humidity coupling cycles. Firstly, the macroscopic performance changes in styrene butadiene styrene polymer (SBS)-modified asphalt mastic were evaluated by the penetration test, softening point test, ductility test, Brookfield rotational viscosity test, and double-edge notched tensile (DENT) test; then, the mechanism of performance changes was explored from the perspective of chemical composition by combining this with Fourier transform infrared spectroscopy (FTIR). The research results show that with the increase in thermal–humidity coupling cycles, SBS-modified asphalt mastic exhibited aging phenomena such as hardening and embrittlement, and its macroscopic performance deteriorated; under the same test conditions, the interval with a higher temperature difference had a greater impact on the performance of the mastic; the sulfoxide index (IS=O) of SBS-modified asphalt mastic increases after thermal–humidity coupling cycles, while the isoprene index (IB) decreases.

Experimental Investigation on Ductility in Fly Ash Aggregate Concrete

Aggregate in concrete is structural filler, which occupies the most of the volume of the concrete The composition, shape and size of the aggregate have significant impact on the workability, durability, strength, weight and shrinkage of the concrete. In recent period some of the aggregates are chemically active and also that certain aggregates exhibit chemical bond at the interface of aggregate and paste. Aggregate occupy 60-80% of the volume of concrete is considerable. The utilization of fly ash in concrete as partial replacement of cement is gaining immense importance today, mainly on account of the improvement in the long term durability of concrete combined with ecological benefits. Three grades of ordinary Portland cement (OPC) are 33,43 and 53 as classified by Bureau of Indian Standard (BIS) are commonly used in construction industry. The main variable investigated in this study is variation of fly ash dosage in 10%, 20%, 30% and 40%. The compressive strength, durability and shrinkage of concrete were mainly studied. The fly ash is collected in Mettur Thermal Power Plant. Then the cement and fly ash proportions of 12.5:87.5, 15:85 and 17.5:82.5 will be adopted to get fly ash aggregates. The particle size distribution, specific gravity, bulk density, impact test on aggregate will be conducted. For the plain concrete and fly ash aggregate concrete of beams (Plain concrete and RCC beams), cubes and cylinders will be cast. All the specimens will be cured in a curing tank. The Ductility test and compressive strength test will be conducted on these plain and fly ash aggregate concrete specimens.

Feasibility Analysis of Resource Application of Dry Flue Gas Desulfurization Ash in Asphalt Pavement Materials

To verify the feasibility of applying dry flue gas desulfurization ash (DFGDA) to asphalt pavement materials, the asphalt mastic (filler and asphalt composition) prepared by adding different proportions of DFGDA and LSP (limestone powder) into 70# matrix asphalt was studied experimentally. The asphalt mastics were subjected to the penetration test, the softening point test, and the ductility test. Moreover, the rheological properties of asphalt mastic were evaluated with dynamic shear rheometer (DSR) tests and bending beam rheometer (BBR) tests. An interaction ability index C-value based on the Palierne model was proposed to evaluate the interaction ability between DFGDA and asphalt. The influence of DFGDA asphalt on the interaction ability of matrix asphalt was observed and evaluated using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results showed that with the increasing proportion of DFGDA, the penetration of asphalt mastic gradually decreased, the softening point increased, and the ductility slightly decreased. At the same temperature, the dynamic shear modulus G* of the asphalt mortar significantly increased with increasing DFGDA content. The incorporation of DFGDA negatively affected the low-temperature plastic deformation resistance of asphalt, but the impact was weakened with the growing DFGDA amount and the powder mastic ratio. The combination mode of DFGDA and matrix asphalt depends on the physical blending, and their interaction ability mainly depends on the miscibility between DFGDA and matrix asphalt. In conclusion, DFGDA can be utilized as a novel filler in asphalt pavement materials.

Effect of Cr on the Hot Ductility of Austenitic Fe-Mn-Al-C Lightweight Steel

In this study, a hot ductility test was performed for Fe-30Mn-10.5Al-0.9C-Cr austenitic lightweight steels. The test was carried out through a commercial Gleeble simulator at a heating rate of 350 °C/sec and cooling rate of 50 °C/sec, with a stroke rate of 50 mm/sec. Microstructural analysis for understanding the hot ductility behavior was conducted through optical and scanning electron microscopy. The lightweight steels exhibited similar hot ductility behavior in accordance with temperature despite the addition of Cr. The experimental results indicated that the κ-carbide precipitation had an insignificant influence on the hot ductility test. However, ductility at low temperature was induced by slip mechanism, while dynamic recrystallization had significant influence at high temperatures during the on-heating thermal cycle. In the on-cooling thermal cycle, the melted and re-solidified grain boundaries decreased the overall ductility, exhibiting the same tendency as that observed in the on-heating test.

Use of Waste Rubber Material as Crumb on Road Construction

Abstract: The growth rate of vehicles is the backbone of economic development of any country. India is the second fast growing automobile industry in the world. In today’s era, solid waste management is the thrust area. On the other side, the traffic intensity is also increasing. As a result, amount of waste tyres is also increasing. The increasing consumption of waste tire has generated many problems such as increasing landfill space, environmental pollution and causing health hazards. Parallel to this is the increasing of roads construction because of heavy traffic on roads. This study reviews to the use of crumb rubber (waste tires in powder form) in bitumen using the wet process. The study focuses on the crumb rubber as a replacement to the total weight of bitumen. The design or life span for all highways and urban roads is 10 – 20 years. Unfortunately, damages or distresses on pavements are still occurring before reaching the maximum period of the designed road serviceability. Among the major influencing factor that is contributing to this distress is the repeated heavy traffic loading on the road surfaces. Moreover, the use of waste crumb rubber in road construction as a pavement surface has a better skid resistance, fatigue crack resistance and increased rut resistance. The review includes physical tests that are used to determine the physical properties of bitumen and modified crumb rubber mix. The physical tests involve penetration test, softening point test, and ductility test. The expectations from the study are to develop bitumen with waste crumb rubber that would minimize the costs of bitumen and providing better physical properties compared to the convention bitumen based on the tests that was conducted.

A Comparative Evaluation of The Mechanical Properties of PET and Polystyrene Modified Asphaltic Concrete Containing Rice Husk Ash Filler.

The study evaluated and compared the influence of bitumen modification for sustainable as- phalt using waste plastic (Polyethylene Terephthalate, PET) and waste Polystyrene (PS) at 5–50% modification levels. Rice husk ash (RHA) and desilted sand were used as filler and fine aggregate with crushed granite as coarse aggregate. Tests conducted include; penetration, viscosity, flash point, fire point, specific gravity, ductility and marshal stability test on asphalt. For PET modi- fied-binder a decrease in penetration and ductility was observed while the specific gravity, vis- cosity, flash and fire points of the binder increased. For the PS modified-binder, the penetration, ductility, viscosity and specific gravity decreased with an increase in PS while the flash and fire point increased. Marshall Stability results showed an optimal of 20% PET modification was ade- quate for medium traffic surfaing with stability, flow, density, air void, void in mineral aggregates (VMA), and Void filled with binder (VFB) of 4875N, 3.53 mm, 2.460 g/cm3, 3.30%, 18.20%, and 81.87% respectively. For 10% PS modification content, the stability, flow, density, air void, void in mineral aggregates (VMA), and Void filled with binder (VFB) were found to be 6825N, 3.33 mm, 2.362 g/cm3, 4.52%, 18.21%, and 75.18% respectively which was found to be adequate for heavy traffic surfacing. Hence, it was concluded that the investigated waste plastics could be used in Asphalt pavement courses. If applied, these results could provide low-cost materials for paving roads while also reducing waste-related pollution and environmental issues.

Multiscale optimization on polymer-based rejuvenators for the efficient recycling of aged high-viscosity modified asphalt: Molecular dynamics simulation and experimental analysis

With the depletion of fossil fuels, the advancement of efficient pavement recycling technology has garnered widespread attention, which contributes to the promotion of sustainable economic and environmental development. The polymers in polymer-based composite rejuvenators (PBCRs) are the key to restoring the performance of aged high-viscosity modified asphalt (HVMA). To optimize the polymers in PBCRs, this study investigates the rejuvenation effect and interface diffusion mechanism of various PBCRs using molecular dynamics simulation and experimental analysis. First, four PBCRs with different polymer components were designed, and their impact on the performance of weather-aged HVMA were examined using the rheological test, low-temperature force ductility test, crack resistance test, and aging resistance test. Subsequently, the rejuvenation effects of four PBCRs were ranked using the comprehensive performance radar chart. Finally, molecular models and layer models of weather-aged HVMA and four PBCRs were constructed, and the diffusion fusion process and interaction mechanism were analyzed using the molecular dynamics simulation. The findings indicate that PBCRs can rebuild the polymer network structure, partially restore the rheology, elastic recovery, and low-temperature ductility of aged HVMA. Additionally, PBCRs significantly reduce the crack potential of aged HVMA and ensure satisfactory aging resistance. Molecular dynamics simulation shows that due to the differences in their molecular structures, the diffusion ability of PBCRs is ranked as follows: crumb rubber rejuvenator (CR + R) > SBR rejuvenator (SBR + R) > SBS rejuvenator (SBS + R) > HVM rejuvenator (HVM + R). In summary, SBS + R proves most effective in regulating asphalt components and rebuilding the polymer network structure, but its interfacial diffusion ability is inferior to CR + R and SBR + R. CR + R has the highest diffusion coefficient, but its rejuvenation effect is not ideal. HVM + R is slightly less effective at rejuvenation than SBS + R, but has the worst diffusion capacity. The rejuvenation effect and diffusion ability of SBR + R are both not ideal. This study has significant implications for optimizing the polymers in PBCRs and promoting the efficient rejuvenation and eco-friendly sustainable development of HVMA.

Bio-Modified Bitumen: A Comparative Analysis of Algae Influence on Characteristic Properties

The main aim of this study was to identify and evaluate the characteristic properties of bitumen modified with algae. Two types of algae, each with distinct gradation and origin, were employed for this investigation. For each type of algae (noted as chlorella and microchlorella), three blends were created with varying algae contents (5%, 10%, and 15% by weight of bitumen), utilizing a 70/100 reference bitumen as the virgin material and a basis for comparison. The properties of the blends were investigated using the Penetration, Softening Point, Elastic Recovery, Force Ductility, Dynamic Viscosity, and Storage Stability tests, both before and after short-term ageing (TFOT). The test results were then used to calculate the Activation Energy (Ea), Viscosity-Temperature Susceptibility (VTS) Index, and Mixing Temperature (Tmixing), along with their respective Pearson Correlation Coefficient (PCC) and R2 and p-values. The main finding of the study was that the addition of a low algae content of 5% caused a change in the classification of the unaged bitumen from 70/100 to 50/70 according to EN 12591 and thus hardened the reference bitumen. Additionally, a strong linear statistical correlation was observed between Ea and the VTS index, suggesting that these values should be considered when characterizing the temperature susceptibility of algae-modified bitumen.

Performance evaluation of asphalt binders incorporating surface-modified diatomite and bio-oil: A value-added utilization of natural resource

To study the effect of surface-modified diatomite (SMD) on bio-asphalt performance, the asphalt binders incorporating SMD and bio-oil (SMDB) was prepared with different dosages. The high-temperature characteristics of SMDB were assessed by consistency test, viscosity test, and dynamic shear rheometer (DSR). Meanwhile, the low-temperature characteristics of SMDB were evaluated by bending beam rheometer (BBR) and ductility test. The compatibility of SMDB was assessed by a storage stability test and a Fluorescence microscope (FM). The adhesion and chemical composition of SMDB were analyzed using the sessile drop method and Fourier transform infrared (FTIR) spectroscopy, respectively. Finally, the moisture stability and high-temperature properties of the SMDB mixture were studied using the tensile strength ratio (TSR) test and wheel track test, respectively. The preliminary results of this work show that the addition of SMD increases the viscosity, softening point, fatigue index, and rutting factor of asphalt and reduces the penetration. It is found that SMD improves the anti-aging performance, adhesion performance, and high-temperature stability of SMDB. Although SMD has a negative effect on the low-temperature properties and fatigue resistance of asphalt, the characteristics of SMDB at low temperatures are still superior to those of virgin asphalt. SMD at low content had little effect on the fatigue resistance of the bio-asphalt. Moreover, it is found that SMD is better than the original diatomite in enhancing bio-asphalt properties more significantly. In addition, the blending among SMD, asphalt matrix, and bio-oil is the physical modification, and the mixture has excellent storage stability. Finally, the mixture property testing results indicate that SMD improves the rutting and moisture resistance of the SMDB mixture.

Effect of Bacillus Subtilis Bacteria on The Mechanical Properties of Corroded Self-Healing Concrete

Reinforced concrete has a weakness for corrosion which can cause the concrete to crack and the concrete structure to fail. To overcome this problem, a self-healing concrete method is needed that can close cracks and inhibit the rate of natural corrosion. Bacillus subtilis as a self-healing agent in concrete has been proven to be able to increase the compressive strength and flexural strength of concrete. The method used in this research is to add bacterial hydrogel encapsulation to concrete with a variation of 0%; 0.1%; 0.6%; and 1.5% by weight of sand. The test object is a reinforced concrete beams and cylindrical concrete with compressive design strength of 30 MPa. The concrete specimens will go through a series of tests, such as corrosion acceleration tests using DC power supply, self-healing tests by visual observation, flexural strength, ductility, stiffness, and compressive strength tests using Universal Testing Machine (UTM). From the test results, it was found that the addition of 0.1% bacterial encapsulation variation was the optimum value for increasing the mechanical properties of self-healing concrete and reduce the corrosion rate on self-healing concrete.

Investigation on One-Component Waterborne Epoxy Emulsified Asphalt (OWEEA) Used as Bonding Material

Due to the issue of weakened adhesion between ultra-thin surface overlays, higher demands have been placed on bonding layer materials in practical engineering. This study proposed a method for preparing a one-component waterborne epoxy resin-modified emulsified asphalt (OWEEA) and explored the impact of different ratios on its performance. The basic physical and mechanical properties of the OWEEA, as well as its rheological characteristics, were investigated through penetration tests, softening point tests, ductility tests, tensile tests, and dynamic shear rheological tests. Pull-out tests and shear tests considering different substrates were used to evaluate the interfacial bonding performance of the OWEEA as a bonding layer material, and comparative analysis was conducted with conventional waterborne epoxy resin-modified emulsified asphalt. Based on microscopic testing and analysis, the laws of physical and chemical changes and secondary curing characteristics of the one-component waterborne epoxy emulsion (OWE) during the modification of emulsified asphalt were elucidated. The results indicated that the OWE prepared in this study significantly enhanced the tensile strength and bonding properties of emulsified asphalt. The results showed that the tensile strength, bonding strength, and shear strength of the OWEEA increased from 0.15 MPa, 0.36 MPa, and 0.35 MPa to 0.55 MPa, 1.29 MPa, and 2.01 MPa, respectively. The modification effect of the OWEEA surpassed that of conventional waterborne epoxy emulsion, albeit with a certain reduction in elongation at break, reduced from 1551% to 98%. Furthermore, the OWEEA showed a distinct secondary curing phenomenon. The results of the SEM tests showed that high temperatures accelerated the formation of the crosslinked network structure of OWE, promoting its integration with emulsified asphalt and resulting in a more uniform and dense structure, significantly enhancing bonding strength in a short period. In the actual road construction process, laying hot-mix asphalt mixtures on the bonding layer can further enhance its curing effect and improve its bonding performance.

Effect of nano-TiO2 on physical and rheological properties of asphalt cement

Abstract In recent years, nano-modified asphalt has gained significant attraction from researchers in the design of asphalt pavement fields. The recently discovered Titanium dioxide nanoparticles (TiO2) are among the most exciting and promising nanomaterials. This study examines the effect of 1, 3, 5, and 7% of nano-TiO2 by weight of asphalt on some of its rheological and hardened properties. The experimental study included physical and rheological properties. The asphalt penetration, softening point, ductility, and rotational viscometer tests indicate that 5% nano-TiO2 is the ideal amount to be added to bitumen as a modifier. The study of the rotating viscosity test showed that the addition of nano-TiO2 helped to increase viscosity and lessen bituminous sensitivity. Rutting factor in terms of G*/sin δ indicated the addition of 3 to 7% of nano-TiO2 increased the rutting resistance of asphalt against higher temperatures and promoted performance grade by about one grade at 3% and two grades at a range of 5–7% this suggests that nano-TiO2 increased the stiffness of the asphalt and leading to enhance the rutting performance of asphalt. While fatigue parameter, G*.sin δ shows that as nanocontent increases, higher stiffness at 5 and 7% of TiO2 content leads to an increase in complex modulus and a decrease in fatigue parameter. Higher creep stiffness and higher m-values were noted at low temperatures as nano increases in asphalt binder, increasing stiffness and decreasing the m-value at −6 and 12°C. As a result, using 5% nano-TiO2 will improve asphalt’s physical properties and enhance asphalt anit-rutting and fatigue resistance.

Optimization design of fiber rubber asphalt gravel sealing layer based on fatigue crack resistance test.

Crack is one of the main diseases of pavement structure. In order to improve the anti-reflective crack ability of pavement, fiber rubber gravel sealing layer is proposed as the stress absorbing layer. In view of the shortcoming that Mcleod design method can not be associated with road performance, a sealing layer optimization design method based on fatigue crack test is proposed. Firstly, the reinforcement effect of fiber on rubber asphalt was studied through force ductility testing. Secondly, the optimum dosage of fiber, asphalt and gravel was optimized through fatigue cracking resistance test. Finally, the cracking resistance of fiber rubber gravel seal was verified through fracture energy test. The results show that fibers can significantly increase the maximum tensile force and strain yield energy of rubber asphalt, and basalt fiber has the best reinforcement effect. The most obvious effect on cracking resistance performance in the sealing layer is the amount of fiber, followed by the amount of asphalt, and finally the amount of gravel. The optimized material combination with the best crack resistance is 120g/m2 fiber, 14kg/m2 gravel and 2.4kg/m2 rubber asphalt, and the fatigue resistance times can reach 19532 times. The fracture energy of the composite pavement treated by the optimized sealing layer is nearly double that of the non-treated pavement structure, and it has a good anti-crack effect.