Asphalt Materials Research Articles

Study of the effect of adding a blend of (ethylene vinyl acetate: styrene butadiene rubber) on the rheological properties of asphaltic materials

Study of the effect of adding a blend of (ethylene vinyl acetate: styrene butadiene rubber) on the rheological properties of asphaltic materials

Homogenization of the elastic-viscoplastic damage behavior of asphalt mixtures based on the mesomechanical Mori–Tanaka method

To improve the efficiency and accuracy in characterizing the nonlinear behavior of multi-phased asphalt mixtures and to further facilitate asphalt pavement design based on the nonlinear properties, this study proposes a homogenized method for the elastic-viscoplastic-damage constitutive model. The Drucker–Prager-type yield surfaces and non-association flow rule were employed to describe the viscoplastic strain of asphalt materials. The continuum damage mechanics (CDM) were incorporated to characterize the evolutions of internal micro-cracks or micro-voids in structures. The mesomechanical Mori–Tanaka (MT) method was used to yield the homogenized nonlinear strain components within multi-phase structures. The proposed constitutive model was then implemented in finite element (FE) simulations based on a self-developed subroutine. Several case studies were conducted, in which composite structures with one inclusion were simulated under constant stress and strain loading rate. Amongst the composite structures, the inclusions with various volume contents and shapes were taken into account. In addition, the influence of air voids in structures was considered by defining the zero stiffness for inclusions. The results indicated that the nonlinear behavior of composite with single aggregate or air void can be effectively represented using the proposed method. Furthermore, by coupling the homogenized nonlinear constitutive relation into the locally homogenous model from previous work, not only was the viscoplastic-damage behavior of the composite with multiple inclusions effectively demonstrated by the definition of the nonlinear material, but the internal heterogeneous feature was also precisely represented by the local cells. Therefore, the proposed homogenized method can effectively predict the viscoplastic and damage behavior of asphalt mixtures with various inclusions by simply specifying the parameters in the FE simulations.

Performance of Asphaltic Concrete Incorporating Fly Ash under Low Temperature

One of the most common asphalt concrete pavement distresses is low temperature cracking, also known as thermal cracking. Characterizations of low temperature cracking and formulation for pavement design have taken a lot of effort. Asphalt binder has viscoelastic behaviour, so asphalt mixture behaviour changes as the temperature changes. At high and low temperatures, the asphalt binder shows viscoelastic plastic behaviour and elastic behaviour. Low temperature cracks that grow day by day due to the movement of vehicles are the most significant pavement cracks caused by cold climates. It needs early and premature repairs to build and expand low temperature cracks. The aim of this research is to perform Low Temperature Cracking analysis of asphalt materials (laboratory and analytical assessment), in light of the latest update of binder cracking temperature. The role of basic material properties in low-temperature cracking was studied in this work. As a result, statistical analysis in the cohesive failure condition revealed that the asphalt mixture aggregate's free energy was ineffective in this cohesion failure. Fly ash had been used in the other type of asphalt mixture. It was proven that the addition of fly ash as an additive can improves the low temperature resistance of the asphalt mix. The binder with 60/70 penetration grade was used. The different amount of fly ash (0%, 1%, 3% and 5%) was added to the asphalt mixture. Marshall Stability and flow, resilient modulus and dynamic creep were carried out to investigate the mechanisms of cracking at low temperature. From the results obtained, there are significant effect comes from the addition of the fly ash. The result show that the addition of 5% fly ash produce the best outcomes for the density, stability, stiffness, resilient modulus and dynamic creep. Thus, it can conclude that the existence of fly ash in the mixture is able to enhance the mechanical performance of the AC14 dense-graded asphalt.

Black Space Rheological Assessment of Asphalt Material Behavior

Abstract Black Space diagrams representing rheological data of asphalt materials in the form of complex modulus (|G*| or |E*|) versus phase angle (δ) have been successfully used for interpretation of material behavior and performance. Previous studies have used Black Space for identification of testing geometry compliance errors when testing over multiple temperatures and loading times (frequencies), screening of the “thermo-rheological simplicity” of various binders and mixtures, and detailed evaluation of the performance balance in term of “stiffness” versus “relaxation” needs. This paper provides an overview of how Black Space can be further used to provide a greater understanding of the concepts of damage and healing and cracking susceptibility and fracture, and to also quantify the complex rheological response of alternative binders. In terms of the damage assessment, cyclic loading tests were analyzed using Black Space to identify additional physical phenomena such as nonlinearity, self-heating, and thixotropy. The cracking analysis has included thermal, fatigue, and durability cracking as well as the use of Black Space to access the performance of asphalt mixtures subjected to aging as well as rejuvenation and materials with recycled asphalt. Concepts such as the Glover-Rowe parameter that are based around Black Space and linked to other forms of rheological indices such as the low-temperature stiffness and relaxation rate parameters are introduced. The results in the paper show that Black Space provides a critical means of rheological characterization to investigate and evaluate the properties and performance of both binders and mixtures. This is particularly relevant at a time when there is a concerted move within the asphalt paving industry toward more sustainable solutions and increased demand for reuse and recycling of materials in asphalt mixtures.

Impacts of recycled binder availability on volumetric mixture design and performance

ABSTRACT The use of reclaimed asphalt pavement (RAP) and recycled asphalt shingles (RAS) in asphalt mixtures is a routine process. Recycled binder availability reflects the proportion of the total recycled binder in a given recycled asphalt material (RAM) that is available to blend with the virgin binder. Studies show that agglomerations of adhered RAM particles preclude complete availability. However, the Superpave volumetric mixture design methods adopted by the majority of state agencies assume complete availability. This study makes use of a sieve analysis method and tracer-based microscopy analysis to quantify recycled binder availability. Revisions to asphalt mix design procedures to account for partial availability are proposed, including consideration of the unavailable binder as part of the bulk aggregate volume and the use of the RAM gradation (i.e. black curve) rather than the recovered aggregate gradation (i.e. white curve) to design the mixture’s aggregate structure. Three high RAM content ‘control’ mixtures that were originally designed under the assumption of complete recycled binder availability are redesigned according to the proposed approach. The redesigned mixtures had notably higher virgin binder content than the control mixtures. The redesigned mixtures also had significantly better cracking resistance than the control mixtures while still meeting permanent deformation requirements.

Comparative Evaluation of Aging Effect Difference between Aging Patterns for Asphalt Binder and Mixture

Abstract Aging simulation methods for asphalt materials can be generally classified into two types: for asphalt binder and for asphalt mixture. Nevertheless, there exists the aging effect difference between aging patterns for asphalt binder and mixture due to differences in aging experimental conditions. The comparison of the aging effect difference between aging patterns for asphalt binder and mixture contributes to building the relationship and thus achieving a conversion of asphalt aging degree between its binder and mixture aging patterns. In this research, aging effect differences between aging patterns for binder and mixture were investigated in terms of short-term aging, long-term aging, and ultraviolet radiation (UV) aging. The binders were collected before and after different aging patterns and then characterized by physical, rheological, and chemical tests. The results indicate that the aging effect difference between thin film oven test and short-term oven aging test is slight, whereas the aging effect of pressure aging vessel test significantly outweighs the effects of long-term aging patterns with loose or compacted specimens. As for photo oxidation aging, the aging effect ranking from the highest to the lowest is UV aging with loose specimen, UV aging for binder, and UV aging with compacted specimen. In addition, regardless of long-term or UV aging pattern for mixture, the aging degree of binder in loose specimen is more serious than that in compacted specimen.

Asphalt VOCs reduction of zeolite synthesized from solid wastes of red mud and steel slag

Asphalt material releases VOCs (Volatile Organic Compounds) during its paving and service periods. Therefore, it is an urgent need to conduct research on VOCs reduction in asphalt materials. This research reused red mud and steel slag to synthesize zeolite for asphalt VOCs reduction purpose. Two-step hydrothermal method was used and the optimized synthesis conditions were studied. The performance of asphalt VOCs reduction resulted from the optimized zeolite was also discussed. Research results indicated that zeolite Y with a specific surface area in 685 m2/g and pore volume in 0.07 cm3/g can be obtained by reusing red mud and steel slag. The pore size of the optimized zeolite is mainly concentrated between 2 and 6 nm. Moreover, addition of optimized zeolite significantly reduces the volume of asphalt VOCs by more than 45%. The incorporation of 5% zeolite performs best in adsorption experiments with the absorption capacity in 60%.

MIXTURE DESIGN AND TEST PARAMETER EFFECT ON FRACTURE PERFORMANCE OF ASPHALT: A REVIEW

Fracture energy is critical for crack evaluation and asphalt mixture design. Thus, the fracture mechanics of asphalt materials should be further investigated. Fracture energy is significantly correlated with factors related to mixture design and testing parameters, as shown in prior studies. Mixture design factors include aggregate gradation and asphalt modification, and test parameters include testing temperature and loading rate. In this systematic review, related studies on the effect of these parameters on the fracture energy of asphalt mixtures are discussed from the perspective of fracture mechanics. Strong relationships between asphalt mixtures’ testing parameters and fracture energy are found in the literature. Moreover, selecting an appropriate loading rate and testing temperature related to the in-service conditions is crucial in evaluating the fracture energy of asphalt mixtures. Good understanding of these relationships can aid in eliminating the fluctuation in the fracture energy results determined in the laboratory. In turn, asphalt’s resistance against cracking can be characterised further.

Dampak Penambahan Campuran Aspal Penetrasi 60/70 Sebanyak 3% pada 1 Lapisan dan 3 Lapisan Struktur Balas

The addition of asphalt material is expected to increase service life and minimize maintenance costs from conventional ballast structures. The purpose of this study was to determine the weight of test material + asphalt 3%, compressive strength, vertical deformation, elastic modulus, abrasion value and damage to the test specimen after loading. The method used was the compressive test method while for the test object used consists of dirty ballast, clean ballast, dirty ballast + 3% asph alt 1 layer, dirty ballast + 3% asphalt 3 layers, clean ballast + 3% asphalt 1 layer, clean ballast + 3% asphalt 3 layers. The test objects were modeled with a cube measuring 0.4 x 0.3 x 0.2 m. The test results show that the addition of asphalt can increase the deformation value and can reduce the modulus of elasticity. However the presence of asphalt as a binding material can minimize the valueof abrasion and damage to the reciprocating constituent material.

Erratum to “Performance Evaluation of Bioengineered Recycled Asphalt Materials”

Erratum to “Performance Evaluation of Bioengineered Recycled Asphalt Materials”

Characterizing the fatigue resistance of multiple modified asphalts using time sweep test, LAS test and elastic recovery test

The fatigue cracking due to the repeated traffic loading is one of the main distresses that reduces the performance and service life of the asphalt pavements. The asphalt phase of asphalt mixture is the most critical for resisting fatigue damage, and thus it must be carefully evaluated for fatigue performance. Previous studies mainly focused on a limited range of asphalt materials while the applications of multiple new kinds of modified asphalts have surged in recent years. This study aimed to evaluate the fatigue resistance of 7 representative modified asphalts, including the linear SBS polymer modified asphalt, crumb rubber modified asphalt, terminal blend (TB) rubberized asphalt, EVA modified asphalt, Rock asphalt modified asphalt and bio oil modified asphalt. Three tests (times sweep test, LAS test and Elastic recovery test) and four different failure criterions are evaluated. Results suggested that elastomeric modified asphalts show the best fatigue performance, followed by non-elastomeric modified asphalts and plain asphalt. Elastomeric modified asphalts appear to show better fatigue resistance at higher strain level conditions. Also, the fatigue life of LAS test shows a good correlation with the elastic recovery, and the correlation improves with increasing strain levels. This suggests that elastic recovery could be a promising indicator for asphalt/mixture fatigue life characterization.

Assessments of moisture damage resistance of asphalt concrete mixtures and asphalt mastic with various mineral fillers

Resistance to moisture damage is crucial for asphalt concrete. Fine-particle mineral fillers have been used to leverage such resistance. This study examines the effects of different types of mineral fillers on the rheology and resistance to moisture damage of asphalt binders and asphalt concrete mixtures. These mineral fillers, namely baghouse dust, lime kiln dust, and hydrated lime, were targeted in this study. These fillers were added to two types of asphalt binders during the initial stage to examine their effects on the rheology of the binders with dynamic shear modulus tests. The effects of the fillers on affinity were evaluated through rolling bottle tests. It was found that mineral fillers can stiffen asphalt binder/mastic, thus providing a higher dynamic shear modulus and better affinity and moisture resistance in terms of a higher percentage of asphalt binder coverage. The properties of asphalt materials were influenced more by filler type than binder type. Hydrated lime provided superior results compared to the others. Consequently, the hydrated lime was used to examine the moisture resistance in the mixture scale in the final stage. It was found that the stiffening behavior can be attributed to the moisture resistance properties in the binder/mastic scale.

Analysis of mixed stiffness modulus of different asphalt levels for AC–BC pavement layer with pertamina 60/70 asphalt and 60/70 esso asphalt material

Asphalt/bitumen is a brownies black material, is viscous so it will soften and melt when it gets enough heating. In general, asphalt is obtained from petroleum refining. Pavement construction in Indonesia, both road rehabilitation project, maintenance and construction of roads, generally. Pertamina 60/70 asphalt is used as a binder for the asphalt mixture. Apart from pertamina asphalt, there are several types of asphalt that ore often used in projects in Indonesia, one of which is esso 60/70 asphalt.Esso asphalt is a type of asphalt produced from foreign companies outside of Indonesia, so it is necessary to do a comparative research test on the Marshall Properties and the stiffness modulus of asphalt. The research was conducted to analyze the stress-strain relationship which show the stiffness and strength of the asphalt material by experimenting with several test objects using the Marshall tool. If the value of the stiffness modulus decreases, asphalt aging will occur which causes the pavement to crack easily when receiving heavy loads. The stiffness modulus analysis of the asphalt mixture is an analytic procedure for planning and evaluating the performance of asphalt mixture. Asphalt mixture is a material that is not perfectly elastic, so the use of the term modulus of elasticity (E) is not suitable, instead the term mixed stiffness modulus is used. The data needed is the value of the stiffness of the asphalt content mixture which was tested by the laboratory to obtain the stiffness modulus and asphalt content characteristic.

GPR application for the characterization of sinkholes in Teresina, Brazil

The town of Teresina, in the state of Piauí, Brazil, presents a history of land sinking processes. Two sinking events deserve to be highlighted, the first occurred in 1999 at Simplício Mendes Street and the other occurred on July 31, 2008, at Francisco Mendes Street. To identify possible shallow caves and associated structures, the Geological Survey of Brazil/CPRM developed a Ground Penetrating Radar (GPR) study to verify the occurrence of reflection patterns characteristic of these dissolution structures. In the field, the team conducted GPR sections along streets with a history of collapse. The GPR results obtained with shielded antennas of 200 MHz allowed the identification of old areas of collapse of the terrain, to a maximum depth of 3 m. In addition, the results obtained by this study show the potential of applying the GPR method in the characterization of the subsoil of paved streets, making it possible to identify various layers: asphalt, actual pavement, subgrade pavement, soil, saprolite, and mixed material. The high clay content of the subsoil does not allow the GPR to investigate further depths in the research area. The interpretation of aero-magnetometric data shows that the occurrence of sinkholes is associated with magnetic lineaments mainly in the NW–SE direction and enhances the understanding of the structural framework of the study area.

Rheological behaviors of asphalt binders reinforced by various fibers

Incorporating different fibers contributes to improving the properties of asphalt materials. In this study, chopped basalt fibers (CBFs), flocculent basalt fibers (FBFs), lignin fibers (LFs), and polyester fibers (PFs) were mixed into SBS modified asphalt at four contents (1%, 2%, 3%, and 4% by weight of SBS modified asphalt) to prepare fiber-reinforced asphalt (FRA) samples for dynamic shear rheology (DSR) tests, including temperature sweep, multiple stress creep recovery (MSCR), and linear amplitude sweep (LAS) tests. The microscopic characteristics of the incorporated fibers and those of the remnants of FRAs after screening out the fibers were also determined using scanning electron microscopy (SEM) and attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR). The results demonstrated that the rheological behavior of FRA varied significantly with the type of fiber incorporated. Generally, the deformation recovery ability and anti-fatigue ability of SBS modified asphalt were improved by adding different fibers. With an increase in the fiber content, fiber network structures were gradually formed in the bundle fibers, including CBFs- and PFs-reinforced asphalt, resulting in an increase in the viscosity and high-temperature stability of FRA. Comparatively, flocculent fibers such as LFs and FBFs presented better improvements in terms of the elasticity, deformation recovery, and fatigue life (Nf) of FRA. The approximate characteristic peaks and values indicate that no chemical reactions were found between the fibers and the SBS modified asphalt. Property analysis revealed that the recommended content was 2%, 3%, 4%, and 4% for CBFs, PFs, LFs, and FBFs, respectively.

Stiffness and fatigue evaluation in cyclic tests with rest periods for asphalt mixtures with or without fly ash

Fatigue of asphalt materials is evaluated in the laboratory by continuous cyclic loading tests, whereas in the field loading is intermittent. Due to such distinction in the nature of loading and possible differences in material behaviour, further study of the effect of rest periods (RPs) on stiffness and fatigue life is of paramount importance. This paper aimed to investigate the effects of rest periods (RPs) on the fatigue life and on the stiffness evolution of asphalt mixtures, including the use of fly ash. The materials used in this research are: three asphalt binders; two granitic aggregate sources from different quarries; fly ash from a thermal power plant. Stiffness and fatigue tests were performed using a servo-hydraulic press. Stiffness characterisation was performed using complex modulus tests at five different temperatures and six different frequencies. Fatigue tests were performed at 19 °C, considering different maximum strain amplitudes in the specimen. Tests with recovery time (5 RPs of 4 h each) were performed. Complex modulus during all fatigue tests was tracked using small, short-period loadings (compared to fatigue loading) during rest. The results show that after significant stiffness decrease during loading, there is a great (about 90% of the total decrease) stiffness recovery during the 4 h RPs, but this recovery is not associated with an increase in the number of cycles to failure in tests with rest. This indicates other phenomena, probably reversible, are responsible for part of the stiffness change during loading.

Zinc Slag as a Partial or Total Replacement for Mineral Filler in Warm Mix Asphalt and Its Effects on Self-Healing Capacity and Performance Characteristics.

Utilizing the self-healing properties of asphalt materials is a way to improve the service life of asphalt pavements. Enhanced self-healing capabilities can be achieved through mixture modification. Using waste or by-product materials to modify asphalt mixtures can provide further environmental benefits. However, with a given mixture modification method, the resulting materials should be adequately vetted to ensure that enhanced self-healing capability is not attained at the expense of the mixture’s overall performance. This research aims to investigate the feasibility of using zinc slag filler to enhance the self-healing properties of warm mix asphalt (WMA) and evaluates the rutting susceptibility and moisture-resistance of the slag-modified mixtures. To this end, zinc slag filler was used to replace a portion of the mineral filler at different replacement rates in WMA mixtures. Self-healing capabilities of the resulting mixtures were studied under microwave induction heating. The influence of zinc slag modification on asphalt mixture’s characteristics and conventional performance indicators were evaluated by the Texas boiling test, the three-point bending test, and the Kim test (a deformation test). Also, the adhesion between bitumen and aggregate was evaluated using the broken sample from the three-point bending test and digital image analysis. The results of self-healing tests demonstrated that the heat generation capability of the specimens increased with filler replacement rate, such that the specimens with 100% of the mineral filler replaced with slag showed the highest heating performance. Zinc slag filler showed the potential to improve the moisture resistance of WMA by enhancing aggregate–bitumen adhesion and thus reducing stripping. The slag-modified WMA samples exhibited better tensile strength ratio (TSR) and deformation resistance than their non-modified equivalents.

Effects of Low-Temperature Construction Additives (LCAs) on the Performance of Asphalt Mixtures.

Green production of asphalt materials is very important to promote energy savings and emission reduction during the construction and maintenance of asphalt pavement. A low-temperature construction additive (LCA) made from the waste plastic and waste rubber is proposed, which belongs to a class of environmentally friendly additives for asphalt mixtures. Marshall stability was tested to evaluate the mechanical performance of LCA-modified asphalt mixtures (LCA-AMs). In order to determine the best preparation parameters of LCA-AMs, the influence of the content and LCA addition method on the strength of LCA-AMs was studied. In addition, the impact of epoxy resin (ER) on the mixtures’ performances was evaluated. The results show that the LCA can significantly reduce the formation temperature of asphalt mixtures, and the resulting asphalt mixtures have good workability in a lower temperature range (90–110 °C). The ER should be added to the LCA-AMs after 4 h of curing. All the volumetric properties satisfy the technical requirements. The low-temperature crack resistance and fatigue resistance of LCA-AMs were obviously improved with appropriate dosages of ER, which can effectively improve the mechanical performance of the asphalt mixtures. The ER can significantly increase the rutting resistance and water sensitivity of LCA-AMs, therefore making it feasible to improve the mixture performance by the enhancement provided by a low dosage of ER.

Crack resistance of fiber‐reinforced asphalt mixtures: Effect of test specimen and test condition

AbstractThe effect of some important testing conditions including test specimen (SCB and ENDB), fracture mode (I and II), loading rate (0.5, 1.0, and 5.0 mm/min), and temperature (−5°C, −15°C, and −25°C) is evaluated on fracture toughness of asphalt material containing different percentages of fibers (0%, 0.025%, 0.05%, and 0.1% of unit weight). The experimental and numerical results show that the addition of 0.025%, 0.05%, and 0.1% of the polyolefin–aramid fiber in asphalt mixture increases the fracture toughness of the control mixture by about 8%, 17%, and 23% in pure mode I and 7%, 16%, and 24% in pure mode II, respectively; which are among the most promising enhancements compared to other fibers. Results also reveal that fracture toughness at mode I obtained from the SCB and ENDB specimens is similar. However, the mode II fracture toughness obtained from the ENDB specimen is about 12% higher than the corresponding value obtained from the SCB specimen.

Value-Added Use of Waste PET in Rubberized Asphalt Materials for Sustainable Pavement

Waste poly(ethylene terephthalate) (PET) drinking bottles and end-of-life scrap rubber tires are common municipal solid wastes discarded and produced every day, which are usually disposed of in landfills and stockpiles, occupying a great quantity of land and causing serious environmental issues. This study aims to first turn waste PET into two value-added derived additives under the chemical treatment of two amines, namely triethylenetetramine (TETA) and ethanolamine (EA), respectively, and then adopt them in association with crumb rubber (CR) to modify virgin bitumen for preparing various rubberized asphalt mixtures. Subsequently, the high- and low-temperature properties of the rubberized binder modified by PET additives (PET-TETA and PET-EA) were comparatively characterized through dynamic shear rheometer (DSR) and bending beam rheometer (BBR) tests, while the rutting resistance, fatigue resistance, and dynamic modulus of the further fabricated mixtures were evaluated and validated through mixture tests. The results obtained indicate that 2 wt.% PET-TETA and PET-EA contribute to increase the rutting failure temperature of asphalt rubber from 82.2 °C to 85.5 °C and 84.2 °C, respectively, retaining the high grade of PG 82; the low-temperature grade of asphalt rubber slightly decreased from PG-28 to PG-22 as the additive was added; the rut depth slightly changed from 3.10 mm to nearly 3.70 mm; and PET-TETA exhibits the potential to be capable of extending the fatigue life of asphalt rubber in contrast with PET-EA at different stress levels within 450 kPa. Based on the findings of this study, the developed recycling approach is considered to be applicable to not only alleviate the environmental concerns caused by the landfills and stockpiles of those wastes but also make them valuable for building more durable pavement.