Aged asphalt binder in reclaimed asphalt pavement (RAP) or recycled asphalt shingles (RAS) blends only partially with the virgin binder. To better understand this state of blending, the asphalt mixtures in this study were designed, mixed, and compacted using different RAP and RAS contents. The asphalt binders were extracted and recovered from RAP and RAS and then blended with different proportions

There are various forms of damage caused by the insufficient shear stress of the bonding coat, if not handled properly, it will lead to serious early damage of the pavement structure. In order to improve the shear resistance of traditional bonding coat, a new pavement method for steel deck is proposed. According to the different particle size and content of crushed stone, 9 kinds of mix proportion

Recently studies reveal that the viscoelasticity of the asphalt layer, the transverse isotropy of each structure layer and the foundation condition of the pavement structure are important factors when analysing the data from falling weight deflectors. However, these factors have not been considered in present analytical solutions simultaneously. To fill this gap, the wave propagation approach was extended

ABSTRACT This research evaluated the effect of different moisture conditions on the ductility, geotechnical and microstructural characteristics of the improved clayey subgrade with various lime contents and geogrid layers. The results of more than 120 tests showed that the combined application of lime and geogrid to the clayey subgrade significantly enhanced the ductility and geotechnical characteristics

In this study, fracture energy and fracture toughness are used to investigate the fracture behaviour of Asphalt Concrete Composites (ACC) in pure mode I and III using Edge Notch Disc Bend (ENDB) geometry at temperatures of −18°C and +25°C. Also, polyester fibre (PE) and calcium lignosulfonate (CL) additives were used separately and simultaneously to improve the performance of ACC's fracture. In order

Stone Mastic Asphalt (SMA) has been broadly used on heavily trafficked roads and motorways in the UK due to its known stability and durability. In this study, several sets of SMA mixtures were produced using different rubberised bitumens, including a Fischer–Tropsch wax pre-treated rubberised bitumen. Properties associated with rutting were evaluated using both linear and nonlinear viscoelastic analyses

Four different subgrade treatment plans are used in the reinforcement treatment tests of soft rock subgrade. When using unscreened gravel and geocell to treat the soft rock subgrade, the average penetration of the reinforcement layer of the subgrade is decreased by 25%, the converted CBR is increased by 46%, and the dynamic deformation modulus is increased by 27%. The soil pressure is attenuated by

This paper investigated the deformation behaviour of K-consolidated sand–clay mixtures through cyclic triaxial (CT) and hollow cylinder (CHC) tests. The sand–clay mixtures contained 0%, 5%, 10% and 20% clay by weight and were prepared at a relative density of 75%. Clay inclusion caused an increase in the permanent axial strain of mixtures (0.075% to 5% in CT and 0.186% to 5% in CHC), while a relatively

This study aimed to evaluate the effects of nano silica (NS) particles on the high-temperature rheological properties of tyre pyrolysis oil (TPO)-modified bitumen. Physical tests, short-term aging, temperature sweep test and multiple stress creep recovery (MSCR) test were conducted to evaluate the effects of NS on the high-temperature rheological performance. Results indicate that the inclusion of

Pervious concrete is a construction material widely used in pervious pavements. Pozzolanic materials replacing partially Portland cement can improve mechanical and hydraulic issues associated with the use of pervious concrete. This paper reports the use of wastes from the sugar cane industry (sugar cane bagasse ash and sugar cane straw ash) and their influence on the mechanical and hydraulic properties

The present work was undertaken to establish the possible threshold values for Surface Free Energy (SFE) and Binder Bond Strength (BBS) methods for screening asphalt-aggregate systems to ensure excellent moisture damage resistance. A total of sixteen combinations of asphalt-aggregate systems consisted of warm mix additives (WMA) and recycled asphalt pavement (RAP) and WMA-RAP combinations. In addition

In this study, dynamic moduli of asphalt mixtures under uniaxial compression (UC), indirect tension (IDT) and four-point bending (4PB) loading modes were tested and incorporated in the MEPDG procedure to predict the pavement responses. The field responses from a full-scale asphalt pavement were used to evaluate the prediction accuracies of three types of moduli. It was found that the current MEPDG

Conventional algorithms are not sensitive to small objects like pavement cracks. We developed a pavement crack detection method based on a convolutional neural network (CNN) with multiple feature layers. The model extracts multi-scale features to increase the accuracy of pavement crack recognition. After hyperparameters tuning, the model accuracy reached 98.217%, and the detection rate reached 96.6

Geopolymer concrete is gaining a lot of attention among researchers across the globe due to its potential contribution to sustainability. Several studies have considered the use of geopolymer concrete for structural elements, but limited attempts have been made on its application in rigid pavements. The current paper investigates the mechanical and durability properties of pavement quality geopolymer

The application of paving fabric along with a fresh asphalt overlay has proved its effectiveness in terms of delaying the propagation of reflective cracks. Nevertheless, this application requires an in-depth knowledge of its mechanical performance under cyclic loading during the design life. In this context, rutting resistance and fatigue failure are commonly employed as major performance criteria

The performance of demolition waste infiledl geocell in subgrade was studied using laboratory flexure testing and subgrade rutting analysis using KENPAVE software. The results obtained were compared with other infill materials: soil and sand. Flexural behaviour was determined using four-point bending tests, with results in terms of modulus improvement factor (MIF). Elastic modulus from the bending

The transformation in axle loads of vehicles along with environmental factors requires stiff base layer for concrete pavement and one such stiff layer is dry lean concrete (DLC). The DLC would have variable stiffness as a result of the construction practices. The present study focuses on understanding the influence of DLC stiffness on the tensile stresses in plain cement concrete (PCC) slab using Finite

Subgrade soil is sometimes modified with lime to improve strength. In this study, lime modified soil (LMS) specimens are subjected to freezing–thawing cycles, the mechanical properties and microstructure of the specimens are investigated by resilient modulus test and scanning electron microscope test. The variation in pore microstructure is investigated by image analysis. The results indicate that

Currently, there does not exist any established test method to evaluate the long-term performance of a porous asphalt pavement against clogging, with or without maintenance cleaning. This study proposes a laboratory test method to bridge this gap. The test method consisted of three main procedures: (i) A procedure to introduce clogging materials into a test specimen, (ii) a procedure to measure the

This study looks into the use of waste clay bricks, in roller-compacted concrete pavement (RCCP). To this end, waste were used in RCCP (at 0% to 100%) as a substitute for sand. Silica fume (SF) was also used to enhance the mechanical properties of the concrete. Mix designs containing 5% to 15% of SF were firstly prepared to determine the optimal amount of SF in the RCCP. Then, SF were used in bricks’

Previous studies have centred on the long-term permanent deformation behaviour of soil under traffic loading while neglecting the dynamic parameters as it is affected by cycle number. In this study, forty tri-axial dynamic tests were conducted to assess the effects of cycle number, confining pressure, and dynamic stress on the dynamic modulus and damping ratio of compacted loess. Empirical models of

This study evaluate the effect of multiple freeze–thaw (F-T) cycles on the mineralogical and mechanical behaviour of cement-stabilised sand samples with 0, 10, and 20% silt. The results showed that in 28-day samples, the replacement of cement with zeolite enhanced unconfined compressive strength (UCS) and California bearing ratio (CBR). The maximum strength was obtained in samples containing 45% zeolite

(2021). Editorial. Road Materials and Pavement Design: Vol. 22, EATA2021 – Vienna, pp. S1-S1.

Moisture sorption can significantly influence hydrothermal ageing and alter the chemical and rheological properties of bituminous mastics. Mineral filler particles are added to bituminous binders to form mastics with increased stiffness. The addition of fillers can considerably change the moisture sorption and the physico-chemical properties of binders by surface interactions and physical presence

ABSTRACT The paper investigates the effects of ageing on the linear and nonlinear viscoelastic properties of bituminous binders for paving applications. Four neat binders were analysed in their unaged state and after long-term ageing, which was simulated in the laboratory with the Rolling Thin Film Oven (RTFO) and the Pressure Ageing Vessel (PAV). Amplitude sweep tests and frequency sweep tests were

Bitumen aging has long been recognised as one of the primary factors that affect pavement’s durability. The amount of rheology-based indexes proposed to track the evolution of bitumen aging level underlines their potential for this purpose. Among these phase angle is a powerful tool since it is highly sensitive to changes that occur in bitumen. Hence, this work aims to estimate the aging level of 23

In pavement engineering, the use of warm mix asphalt (WMA) technologies can ensure important environmental and technical benefits. However, several uncertainties about WMA still exist, such as long-term field performance and full compatibility with reclaimed asphalt pavement (RAP) or polymer modified bitumen (PMB). In this regard, a full-scale trial section (including three test fields with warm recycled

Incorporating reclaimed asphalt (RA) in surface layer mixtures is still limited due to performance concerns, and it becomes even more challenging when combining aged polymer-modified bitumen (PMB) with virgin PMB. This study aims to evaluate, from a binder perspective, the feasibility of incorporating reclaimed polymer-modified binder (RPMB) in new surface layer mixtures. To address this challenge

The use of recycled polymers as bitumen modifiers contributes to extending their application at a competitive cost being also a more sustainable solution. However, despite several studies proving their benefits in asphalt mixtures, their use is not yet widespread. Hence, this research explored the long-term performance of bituminous materials made with two of the most common recycled polymers (household

Extrinsic self-healing of bituminous materials using encapsulated rejuvenators is a hot topic within road materials. Based on a circular economy vision for more sustainable and resilient asphalt pavements, this study explores for the first time the use of pyrolytic oil from waste tyres as a promising encapsulated rejuvenator to promote the extrinsic self-healing in bituminous materials. Pyrolytic oil-in-water

Asphalt binder ageing alters its chemical and physical properties in a manner to make it brittle and more susceptible to thermal and fatigue cracking. The ageing rate of asphalt binders depends on a combination of different factors related to their chemical composition, environmental conditions and mix design. In order to prevent ageing, anti-ageing additives are used. The selection of the optimal

There is still no consensus on the most appropriate compaction method for the assessment of cold recycled asphalt mixtures (CRAMs). A limited number of studies sought to identify the effects of different compaction methods on the CRAMs mechanical properties. Effects of CRAMs compaction method (Proctor, Marshall, Gyratory and Vibratory) were evaluated in terms of physical properties, mechanical tests

Since the adoption of the Performance Grading criteria, researchers and agencies have dedicated efforts toward supplementing the existing parameters with better indicators of asphalt binder cracking susceptibility. This study seeks to evaluate the relationship between ΔTc and the Glover-Rowe parameter, two such parameters. This study contains three parts: (i) a fundamental examination of the relationship

The first objective of this study is to highlight the effect of the rejuvenator on the linear viscoelastic (LVE) properties of various blends of a fresh 50/70 binder and a reclaimed asphalt pavement (RAP) binder, with a rejuvenator (a mixture of vegetal oils). A total of 17 binders (including pure fresh and RAP binders) produced as blends of two base binders and a rejuvenator in various proportions

In recent years, over-stabilized polymer-modified bitumen emulsions have been widely used to improve the mechanical properties of cold bituminous mixtures. However, the effect of the polymer modification process on the emulsion performance have not been investigated. The present paper deals with the analysis of the binders recovered from a reference unmodified bitumen emulsion and two polymer-modified

The performance of cold bitumen emulsion (CBE) mixtures is strongly linked to an optimised design of the binder blends and mastics. Types and dosages of bitumen, mineral additions and the workability must be characterised and optimised. This study aims at providing an approach for the fundamental characterisation of CBE materials using rotational viscometry. Firstly, a procedure for measuring the viscosity

Crumb rubber modified bitumen (CRMB) can be regarded as a binary composite system in which swollen rubber particles are embedded in the bitumen matrix. The current study aims to further improve the prediction accuracy of micromechanical models for CRMB by considering the interparticle interactions. To accomplish this goal, two different strategies were used. Firstly, the (n+1)-phase model was applied

The paper briefly discusses traditional asphalt pavements designing methods of designing of asphalt pavements developed in the second half of the 20th century. In comparison, it presents the assumptions and derivations of a modern method based on the simplified viscoelastic continuum damage (S-VECD) model together with its necessary input data. In the second part of the article, structures for two

Chemical composition influences inter-molecular interaction and structuring within bitumen. Additionally, microstructural properties affect physical properties like viscosity and more complex rheological properties like thixotropy. Thixotropy is a reversible phenomenon that is caused by the breakdown of microstructures as a result of deformations from the applied stress. In this study, a manifestation

The use of modifiers for bituminous binders has become common practice to enhance the performances of asphalt materials. As a result, the binder becomes more complex, with various phase morphologies. Conventional testing methods may not always be suitable. As example, the European standardisation committee is looking at different ways to characterise Polymer modified Bitumen. The RILEM Technical Committee

The broad characterisation with many techniques of the chemical / rheological properties of bitumen is rather challenging and complex, even more as these properties change during ageing and by using additives. Therefore, it would be highly desirable to reduce the analytical effort by using chemometrics to predict these properties. Here, we present a chemometrical study based on mid-infrared (MIR) and

Mastic and mortar are two bituminous composites which play a fundamental role in defining bituminous mixes’ properties. Therefore, the main purpose of this paper is to study the behaviour of these materials according to time and frequency with three different approaches: Experimental, analytical, and numerical. To characterise bitumen, mastic, and mortar, a Dynamic Oscillatory Test was carried out

This paper employs the linear viscoelastic parameter G′/tanδ as the quantitative criterion for identifying a common relationship with the Ring and Ball softening point of both unmodified and polymer-modified bitumen (PMB). Temperature sweep was conducted at 10 rad/s with dynamic shear rheometer to determine the complex shear modulus G* and phase angle δ of bitumen. The parameter G′/tanδ could be obtained

A laboratory study was done on three bitumen of penetration grade 50/70 from three sources and three corresponding mastics made using these three base bitumen and one filler – Limestone. The tests were all done using the Dynamic Shear Rheometer (DSR), including frequency sweeps for rheology, single stress creep recovery test (SSCR) for permanent deformation behaviour, Dresden cryogenic test (DDCT)

Asphalt mastic is known to play an important role when determining the fatigue performance of asphalt mixture. Time sweep test using a Dynamic Shear Rheometer can be used. However, a long testing time is a major disadvantage, and no guidelines for testing asphalt mastic are available. Therefore, this study presents an Accelerated Dynamic Shear Rheometer Fatigue Test (ADFT) for fatigue testing of asphalt

Asphalt mastic, the combination of fine-grained mineral particles and asphalt binder, plays a significant role on the performance of Hot Mix Asphalt mixtures. A clear understanding of the effects of both filler and asphalt binder, and their interaction, on the properties of HMAs is critical to ensure a proper mix design and pavement performance. Several researchers have studied the response of the

Viscoelastic characterisation of asphalt mixtures is an important component for modelling and performance prediction of flexible pavements. In this study, using spherical indentation testing for measuring the viscoelastic properties of asphalt is explored. Indentation testing may provide an interesting alternative to existing experimental techniques, as it is capable of characterising small material

The aim of this paper is to show the complexity of studying air void topology by giving an in-depth literature review. Factors defining air void structure are presented and relationships and correlations are highlighted. The hydraulic conductivity of asphalt is then put in context of air void analyses. A new approach to distinguish constrictions in the air void matrix is introduced. The bigger air

Regular and long-term infrastructures monitoring is fundamental for asset management, as it provides information on the actual mechanical conditions and triggers maintenance actions. Several tools are currently used for this purpose, such as embedded sensing devices, deflection measurements and visual inspections. In this paper, we analyse data from a full-scale experiment performed on the accelerated

The degree of adherence between two bituminous layers can be assessed from shear tests carried out at constant displacement speed, which allow the shear strength and stiffness of the interface to be obtained, being usual to specify a minimum strength. But stronger bonds will be more stressed, which could negatively affect their fatigue behaviour. In this work, the shear fatigue behaviour of two interfaces

Compaction of asphalt mixtures is a critical component of the construction process of asphalt pavements. The quality of compaction has a significant consequence for the durability of asphalt pavements. Compaction of asphalt mixtures is a complex physical process, which has not been fully understood. In this study, we investigate the physical mechanisms of compaction, based on which we propose a new

The interlocking of aggregate is critical during compaction. Nevertheless, few mix design specifications include any specific requirements for locking points, mainly because it is difficult to determine when interlocking happens during compaction precisely. This study's objectives were to validate the locking point concept by applying performance tests and evaluating aggregate interlocking influence

The linear viscoelastic (LVE) characterisation of asphalt mixtures in time domain is generally performed at temperature lower than 30°C to prevent the effect of permanent deformation. Although LVE properties in frequency and time domain can be mathematically interconverted, the determination of relaxation modulus and creep compliance through experiment is also necessary. This paper presents a method

ABSTRACT The classical modelling of fatigue tests carried out in the laboratory on asphalt concrete consists in predicting the decrease in the overall complex stiffness modulus. However, this approach is limited because reversible phenomena, called biasing effects (nonlinearity, self-heating and thixotropy), develop in parallel with damage. The VENoL (T,ω,ε0) model is already able to reproduce tests

In order to explore the potentials of a foam-based warm-mix asphalt(WMA) technology for the production of EME2 mixtures, an extenstive laboratory study was carried out. In this study EME2 mixtures incoporating 0% and 30% reclaimed asphalt (RA) were produced at 120°C using WMA technology. As control mixtures, hot-mix variants of these mixtures were also produced at 180°C. The performances of these mixtures

Longer Heavier Vehicles provide an improvement in energy efficiency and environmental performance compared to traditional Heavy-Duty Vehicles. In Sweden, the maximum permissible vehicle gross weight has been increased from ∼64 to ∼74 tonnes without increasing the axle load limits. The consequence of this is investigated in this study. Response from two instrumented thin flexible pavements subjected

This paper presents an Acoustic Emission characterisation of the damage behaviour of asphalt concrete subjected to bending fatigue loading. An experimental campaign is carried out on an old asphalt concrete extracted from an in-service highway pavement, built-in 2001. Tests were performed in strain-controlled mode with an amplitude of 175 µstrain, a frequency of 25 Hz, and at 10°C. Failure criteria

Compared to typical asphalt mixtures, poroelastic mixtures are characterised by high porosity and high flexibility, which are desirable for traffic noise reduction. However, the same properties increase the risk of debonding from the lower layer, which is a significant source of premature damage. The study investigates which of the factors – tack coat agent, type and texture of the lower layer – have

This study investigated the engineering, economic, and environmental feasibility of asphalt mixes containing brick dust (BD), recycled concrete aggregate dust (CD), limestone slurry dust (LD), rice straw ash (RSA), glass powder (GP), carbide lime (CL), and copper tailing (CT). The performance of asphalt mixes containing various wastes was evaluated against rutting, cracking and moisture sensitivity

New regulations on bitumen fumes and aerosols, along with increasing traffic and climatic loads on highways, demand innovative construction materials. In this investigation, a novel isocyanate-based bitumen additive was used to pave 0.5 km of an asphalt binder layer with 50% reclaimed asphalt at 20-30°C below hot mix asphalt (HMA) temperatures, in Germany. During construction, bitumen fumes and aerosols