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This paper evaluates the strength performance of hot mix asphalt produced with High Density Polyethylene (HDPE)-modified bitumen and Reclaimed Asphalt Pavement (RAP) which is partially replacing virgin aggregates. Asphalt Institute blending chart was used to determine the quantity of Reclaimed Asphalt Pavement (RAP) incorporated into the mixture. Thermo-gravimetric Analysis and Differential Thermal Analysis (TGA/DTA) were used to determine thermal stability of the High Density Polyethylene (HDPE). Fourier Transform Infrared (FTIR) was used for characterization of the HDPE, bitumen and modified bitumen. Physical test conducted on the RAP and virgin aggregates in accordance with American Society of Testing Materials (ASTM) standards revealed that the aggregates are adequate for use in asphalt production. Marshall method of mix design was adopted for the hot mix asphalt production and testing. With respect to the threshold, the results of Marshall stability showed a 6% increase in the strength of the asphaltic mixture modified with 10% High Density Polyethylene (HDPE). Other Marshall properties tested also showed improvements. Scanning Electron Microscopy and Energy Dispersive X-ray Spectrometry (SEM/EDS) were used for micro-structural examination and composing elements analysis of the asphaltic mixture, respectively. Fibermetric analysis was used to explore the fiber content and pores within the mixture. [ABSTRACT FROM AUTHOR]

In recent time, more polyvinyl chloride (PVC) plastic are produced than what is currently being recycled, that contributes to the volume of waste. This occurrence prompted the exploration of polymer modified bitumen (PMB) to address the waste concern and thereby cuts cost in bituminous mix and improves pavement performance. This research evaluated the strength properties of asphalt mixture produced with polyvinyl chloride modified bitumen. Marshall method of mix design was used in the production of hot mix asphalt (HMA). Scanning Electron Microscopy (SEM), Fourier Transform Infra-red (FTIR) and Energy Dispersive X-Ray Spectrometry (EDS), used for microstructural examination and elemental analysis. These materials conform with its physical properties and characteristics. The shredded, grinded plastic revealed high binding properties when blend with bitumen. The percent incorporated was 2 - 10% PVC content and the Optimum Bitumen Content obtained was 10%, at 9.57kN for stability. The modified bitumen for penetration recorded at 68mm, which conformed with 60/70 grade bitumen, softening point recorded at 52oC, ductility was recorded at 107cm, specific gravity at 1.02, flash and fire point at 294oC and 306oC, solubility at 97% respectively. The properties were satisfactorily for grade 60/70 bitumen at 4% PVC by weight and be used as bitumen modifier for heavy traffic condition. Polyvinyl Chloride modified at 8 - 10%, be used at cold climates, while 2, 4, 6% PVC modified be used in warm regions. Therefore, the experiment proved these materials with characteristics, stability and stiffness be used for pavement constructions.

Different types of additives are used in asphalt modification to enhance several properties within the asphalt pavement. In various cases, modification is needed by using multiple additives, which is called composite modification. In this study, glass fibre and nano clay were used to modify the asphalt pavement. The amount of these two additives, together with the optimum bitumen content, was determined by the response surface methodology (RSM). Central composite method (CCD) was used for determining the optimum amount of independent variables (nano clay, glass fibre, bitumen content), by evaluating the dependent variables. Marshall mixture design criteria and minimum bitumen content, were the optimal conditions. As a result, the mixture containing 0.2% glass fibre, 3.693% nano clay and 4.096% bitumen content, was predicted to give the most desirable characteristics. Additionally, verification tests were conducted to evaluate the adequacy of the predicted model. The results were within the 95% confidence intervals for all response variables, which demonstrates the validity of the model obtained in the study. Consequently, CCD can be used to obtain design optimisation of asphalt modification with less mixture production for experimental stages. This is a substantial advantage, which supports human safety and environment- friendly practices. [ABSTRACT FROM AUTHOR]

Sb2O3 nanoparticle was selected as it is expected to reduce the aging effect on bitumen, and is a novel material hasn’t studied yet in the literature. Bitumen was modified by antimony trioxide (Sb2O3) nano particle. The rutting performance of Sb2O3 modified bitumen and the performance of Hot Mix Asphalt (HMA) was investigated. Multiple stress creep recovery (MSCR) test was performed. HMA mixtures were tested using the Indirect Tensile Strength (IDT) test. HMA mixtures were aged in the oven for short and long-term aging before conducting Hamburg Wheel Tracking (HWT) test to determine the rutting performance of the HMA mixtures. After aging, Sb2O3 modified bitumen becomes more resistive according to the results of both the bitumen and HMA tests. As a result, three percent Sb2O3 modified bitumen had better performance similar Jnr and R%. The best rutting performance was determined for 3% Sb2O3 modified bitumen with 4.3 mm rut depth.

It is imperative to develop a means of utilizing municipal solid waste incinerator ash (MSWIA) for a proper environmental protection. Hence, this research is to evaluate the influence of municipal solid waste incinerator ash (MSWIA) as a substitute for fine aggregate in hot-mix asphalt concrete. The physical properties and chemical oxide composition tests were carried on MSWI ash with the view of evaluating its suitability for used as fine aggregate. Marshall mix design method was adopted for sample preparation. Preliminary samples were prepared to determine the optimum bitumen content (OBC). The OBC was determined as 5.5% and was used for the preparation of samples with varying proportion of MSWIA (10%, 20%, 30% and 40 by total weight of the fine aggregate). The samples were subjected to mechanical and volumetric evaluations, which include stability, flow, bulk specific gravity, void in mineral Aggregate (VMA) void filled with bitumen (VFB) and Voids in the mix (VIM). The results revealed that the flow, void in mix (VIM), void in mineral aggregate (VMA) increased, while bulk specific density (BSD) and void filled with bitumen (VFB) became less as the percentage of MSWI ash raised. However, the use MSWI ash in the preparation of hot mix asphalt as a substitute for fine aggregate should not be beyond 20 % MSWIA. Moreover, the results fulfilled the Standard Specification and requirements specified by Nigerian Standard Specification for Roads and Bridges.

By modifying the conventional and mechanical properties of bitumen and asphalt mixtures with recycled additives such as Recycled Glass Powder (RGP) as well as new additives such as Carbon Nanotubes (CNTs), in addition to improving the properties of bitumen and asphalt mixtures, it can also be environmentally friendly. For the first time, this article evaluated the rheological and mechanical properties of bitumen and Hot Mix Asphalt (HMA) with CNTs and RGP. For this purpose, a total of 17 types of asphalt mixes were made. CNTs and RGP were added to bitumen with aggregate at different percentages. Finally, an economic analysis was conducted for a 3-Line road. The results of the rheological properties of bitumen showed that adding additives reduced the thermal susceptibility of bitumen. Also, the results of the Marshall Test showed that the stability of samples containing RGP and CNTs increased due to the more effective presence of CNTs compared to the presence of RGP. Moreover, it was found that the Marshall ratio of the modified samples increased. Economically, the addition of RGP and CNTs led to an uneconomical design. Finally and considering all aspects, C1G25 asphalt mix is recommended due to technical-economical properties. [ABSTRACT FROM AUTHOR]

Sb 2 O 3 nanoparticle was selected as it is expected to reduce the aging effect on bitumen, and is a novel material hasn't studied yet in the literature. Bitumen was modified by antimony trioxide (Sb 2 O 3) nano particle. The rutting performance of Sb 2 O 3 modified bitumen and the performance of Hot Mix Asphalt (HMA) was investigated. Multiple stress creep recovery (MSCR) test was performed. HMA mixtures were tested using the Indirect Tensile Strength (IDT) test. HMA mixtures were aged in the oven for short and long-term aging before conducting Hamburg Wheel Tracking (HWT) test to determine the rutting performance of the HMA mixtures. After aging, Sb 2 O 3 modified bitumen becomes more resistive according to the results of both the bitumen and HMA tests. As a result, three percent Sb 2 O 3 modified bitumen had better performance similar Jnr and R%. The best rutting performance was determined for 3% Sb 2 O 3 modified bitumen with 4.3 mm rut depth. [ABSTRACT FROM AUTHOR]

Overwhelming increase in plastic waste since recent years became series ecological issue for both developed and developing countries. Compromising the large plastic waste potential in Ethiopia and poor pavement performance in the roads due to severe weather and high traffic loads, it is viewed to use this in-hand resource as asphalt modifier to urge sustainability, enhance the stability of asphalt mix and reduce the amount of bitumen used. The study aimed at investigating the effect of using waste LDPE plastic as a modifier of virgin bitumen. This study also tries to amplify the advantage of using wet blending method over dry. Four modified bitumen mixes prepared with 4, 6, 8 and 10% waste LDPE plastic content by the weight of optimum bitumen content (OBC) at different mixing temperatures (160, 170, and 180 °C) and different mixing times (1, 1.5 and 2 hours) to evaluate penetration point, softening point and ductility. 170 °C mixing temperature and 1.5 hour mixing time results, homogeneous mix between bitumen and waste LDPE plastic materials compared to other mixing temperatures and mixing times. Marshall Test Method was used to determine the optimum bitumen content and to evaluate the marshal properties of the plastic modified asphalt mix. The OBC of non-modified marshal sample was found to be 5.16% by weight of the total aggregate while the optimum waste LDPE modified bitumen content was found to be 6.5% by weight of the OBC. Asphalt mix modified with 6.5% of waste LDPE plastic content has 33.67% higher stability value compared to the non-modified asphalt mix.

There is a huge demand of aggregates for the construction of roads and concrete constructions in Pakistan. The construction of roads for high-speed traffic and heavy axle loads put enormous pressure on road materials. Many public sectors as well as private organizations are carrying out a wide range of research projects on the environmental, feasibility, and economic performance of using industrial waste products in the construction of roads. This study is attempted to fulfill the needs of society in the safe and economical disposal of waste material. This research aims to explore the potential use of copper slag (CS) as a replacement of fine aggregate and filler material. Comparison of conventional HMA samples and HMA samples having some percentage of copper slag as a replacement of fine aggregates. First, test aggregates and bitumen with 0% copper slag to determine their mechanical properties. Make samples and add bitumen percentage (3.5%, 4%, 4.5%, 5%, and 5.5%). Copper slag was added with 5%, 10%, 15%, 20%, 25%, 30%, 35%, and 40% by weight. In the end, the tests were performed on the Marshal Apparatus. The experimental results showed that the addition of 20% of copper slag as fine aggregates has maximum Marshall Stability, a higher flow rate, maximum VFB and specific gravity slightly increases as compare to conventional HMA. Therefore, the strength is maximum by the addition of 20% copper slag, so we can use it in heavy traffic lanes and runways. Copper slag is economical as compared to other fine aggregates, so it should be implemented in Pakistan. Sufficient research has been conducted in Pakistan since it’s not being implemented frequently. Therefore, we have some solid reasons, conclusion and recommendations in this research.

Aggregates are the principal material in pavement construction. Conventional road aggregates in India are natural aggregates obtained by crushing rocks. The physical properties of coarse aggregate are more significant in new generation bituminous mixtures. Aggregate characteristics such as particle size, shape, and texture influence the performance and serviceability of hot mix asphalt pavement. The shape of aggregate particle has significant influence on performance of the Bitumen pavement. Particle shape can be described as cubical, blade, disk and rod .The strength serviceability requirements of Bitumen mixes such as stability, flow, voids in mineral aggregate (VMA), voids filled with bitumen (VFB) and air voids are highly depend on the physical properties of aggregate. Dense bituminous macadam (DBM) mixes were analyzed with different proportions (10%, 20%, 30%, 40%, 50%) of different shape of aggregates were studied. Mixes with cubical and rod shape aggregates has been showed good results on stability. The parameters such as air voids and voids in mineral aggregate increases with increase in proportion of blade type of aggregates in DBM mixes. The particle index value of coarse aggregate significantly affected the engineering properties of Hot mix asphalt (HMA) mix. The particle shape determined how aggregate packed into a dense configuration and also determined the internal resistance of a mix. Mixes prepared by replacing 20% aggregates shown higher stability values. Cubical particles exhibit interlock and internal friction, and hence results in greater mechanical stability than the blade, rod, and disk shape aggregates. Particle shape parameter values obtained were higher for cubical shape aggregates and lower for blade shape aggregates. [ABSTRACT FROM AUTHOR]

The predicted performance and service life of the pavement depend largely on the properties of bitumen used in the mixtures. The most important feature of bitumen, which has profound effect on the performance of the road is durability. The durability of bitumen is expressed as the resistance to aging. In this study, the bituminous mixture aging was performed instead of bitumen aging in order to represent the aging in the field in the best possible way. The aim of this paper is to evaluate different proposed laboratory aging methods (NCHRP 09-52, NCHRP 09-54 and RILEM) in relation with the current Standard AASHTO R30 (Standard Practice For Mixture Conditioning of Hot Mix Asphalt standard) and to make comparison with the samples performance taken from the field in terms of Indirect Tensile Strength (ITS). The level of aging has also been compared with the samples taken from recently constructed pavement surface and from the five years old pavement surface. Results depicted that, laboratory aging methods revealed the field aging properties on the unaged bitumen. Based on the results, 2 hours forced draft oven aging at 135°C is recommended as short term aging condition because, 2 hours or 4 hours short term forced draft oven aging did not yield significant variation in terms of ITS values. Additionally, 120 hours (5 days) oven aging of compacted samples at 85°C can be recommended as long term aging condition. [ABSTRACT FROM AUTHOR]

This work evaluate the influence of waste pure water sachet (WPS) as a modifier in Hot Mix Asphalt (HMA). The properties of the constituent materials were determined. Modified HMA samples were prepared at varying concentration of 2, 4, 6, 8 and 10% WPS content by weight of the Optimum Binder Content (OBC). The properties of the modified HMA were determined using Marshall Method of mix design. The properties of the constituent materials showed that they are suitable for HMA production. The modified bitumen showed an increase in softening point (61 - 73.5%), flash point (258 - 282°C), fire point (289 - 311°C) and ductility (92.67 - 118.67cm) as the WPS content increases from 2% to 10% while decrease in penetration (62.33 - 56.5mm) as WPS content increases from 2% to 6%. Stability and Bulk density increases from 4.64kN to 8.84kN and 2.21g/cm³ to 2.34g/cm³ respectively while flow, voids in mineral aggregates (VMA) and Air voids decreases from 3.6 to 2.98mm, 23.85 to 20.16% and 19.73 to 13.97% respectively as the WPS content was increased from 2 to 8%. An optimum polyethylene from WPS modifier content of 8% by weight of the OBC is recommended for use in the HMA. [ABSTRACT FROM AUTHOR]

This study evaluate the use of Disposable Food Pack (DFP) as a modifier for bitumen for an improved Hot Mix Asphalt (HMA). The bitumen was modified with 2%, 4%, 6%, 8% and 10% DFP obtained from domestic waste. The penetration, ductility and specific gravity of DFP modified bitumen decreased from 68mm to 59.5mm, 110cm to 101cm and 1.025 to 1.012 respectively with increase in DFP, while softening point increased from 49.5°C to 54.5°C with increase in DFP. The Marshal Stability results revealed that the DFP modified bitumen increased the stability values of the compacted mixes to a maximum of 9.33kN at 8% DFP content. The flow showed decrease from 3.18mm at 2% DFP to 2.94mm at 10% DFP, whereas the density of the compacted mixes increased to a maximum of 2.293g/cm³ with increased modifier. An Optimum DFP Content of 6.7% by weight of the Optimum Bitumen Content (OBC) is recommended. [ABSTRACT FROM AUTHOR]

In this study, four different additives (Styrene–butadiene–styrene (SBS), Trinidad Lake Asphalt (TLA), Iranian Gilsonite (IG) and American Gilsonite (AG)) were used in bitumen modification. The rheological properties of bitumen were improved with the additive usage, and the desired performance grade (PG 70-34) was achieved by using additives in pure bitumen (PG 58-34) at the indicated ratios. Wheel tracking tests and semi-circular bending tests were applied for hot mix asphalt (HMA) samples. The main results showed that all the additives increased resistance to permanent deformation of HMAs, and that TLA was the most effective additive. In addition, it was found from the semi-circular bending tests that deformation values of mixtures prepared with modified bitumens and subjected to long-term ageing decreased. As a result, long-term aged and modified bitumen mixtures exhibited more brittle behaviour. The increase in maximum load values led to an increase in the area under the load-strain curves. Thus, crack propagation resistance of mixtures prepared with modified binders was increased. [ABSTRACT FROM AUTHOR]

The use of molasses as a replacement for bitumen could benefit the pavement industry by improving the performance of the pavement or by lowering its cost. An experimental investigation was carried out to investigate the effect of molasses with different moisture contents on the property of hot-mix asphalt (HMA). Bitumen binders (BB) containing 5%, 10%, 15%, and 20% molasses were investigated as molasses modified binders (MMB). Molasses with 24.9% and 5.02% by weight of water were used to investigate the effect of moisture on the MMBs. In addition to the conventional binder tests, additional tests such as the Fourier transform infrared (FTIR) test, amplitude and frequency sweep test, performance grade (PG) test, and multiple stress creep recovery (MSCR) test were performed. The results indicated that most of the properties of the MMBs improved with the reduction in the moisture content of molasses but worsened with the percentage replacement of molasses. The IR spectra show that the carbonyl index decreased with an increasing amount of molasses. The control grade PG58 was improved to PG64 and PG70 when the base binder was modified with molasses and aged with rolling thin film oven (RTFO) consecutively. At a temperature of 58 °C, non-recoverable creep compliance of 3.2 kPa (Jnr3.2kPa) was decreased for each MMB, which leads to improved rutting potential. At a temperature of 64 °C, the Jnr value was decreased only for the MMB containing 5% molasses, and then gradually increased for the remaining MMBs. Generally, the study revealed that low moisture content molasses could be used as a partial replacement for bitumen to enhance the rheological properties of the bitumen. [ABSTRACT FROM AUTHOR]

Storage of various products obtained from wastes or leaving these to the nature lead to many difficulties and huge problems such as environmental pollution. Today, some studies are carried out on the recycling of wastes and by-products gained during the manufactory of various products. Wastes can be used to obtain new products or as an additional substance on the existing products. Both recycle of wastes and by- products prevents damage to the environment and reduces the occurrence of related problems to a minimum level by mitigating the usage of very scarcely found natural substances. Thus, it is important that industrial wastes be gained to state economy through being recycled for various uses. In recent years, studies on removal of wastes by recycling on highway layers have been extended. The aim of this study is to introduce the technical advantages of plastic materials known only as a simple waste material and to convert the environmental, economic and technical disadvantages of these materials as waste as an asphalt coating material. In the study, the samples were prepared by mixing bitumen with bituminous waste plastic heat treatment method and prepared samples were subjected to Marshall Strength and Indirect Tensile Strength tests and the results were interpreted. [ABSTRACT FROM AUTHOR]

The present study evaluates the mechanical performance of a Hot Mix Asphalt – Type II (HMA-2) modified with carbon nanotubes and carbon nanofibers (CNTF). CNTF were made by means the Catalytic Vapor Deposition (CVD) technique at 700° C using a Nickel, Copper and Aluminum (NiCuAl) catalyst with a Cu/Ni molar relation of 0,33. In order to properly assess HMA-2 performance, three different mixtures were analyzed: 1) HMA-2 modified with purified CNTF; 2) HMA-2 modified with non-purified CNTF and, 3) a Conventional HMA-2 (control). Samples manufactured in accordance with the Marshall Mix Design were tested in the laboratory to study rutting, resilient modulus (Mr) and fatigue. In addition to the aforementioned dynamic characterization, the effect of CNTF purification on the asphalt mixture’s mechanical properties was analyzed. In short, a comparative study was designed to determine whether or not CNTF should be purified before introduction into the HMA-2. This investigation responds to the growing demand for economical materials capable of withstanding traffic loads while simultaneously enhancing pavement durability and mechanical properties. Although purified CNTF increased HMA-2 stiffness and elastic modulus, non-purified CNTF increased the asphalt mixture’s elastic modulus without considerable increases in stiffness. Thus, the latter modification is deemed to help address fatiguerelated issues and improve the long-term durability of flexible pavements.

Due to the special characteristics of nanoparticles, pavement engineers have used nanoparticles as an additive in asphalt pavement to improve pavement performance. This study focuses on characterizing modified asphalt performance using nanoclay particles compared to the unmodified asphalt binder. For this evaluation, 3% of nanoclay particles were added to a neat binder to prepare the nanomodified binder. Then, the modified and unmodified binders underwent a short- and long-term aging process using the Rolling Thin Film Oven (RTFO) and two cycles of Pressure Aging Vessel (PAV). Finally, the Dynamic Shear Rheometer (DSR), Bending Beam Rheometer (BBR), and Fourier-Transform Infrared Spectroscopy - Attenuated Total Reflection (FTIR-ATR) tests were carried out in each aging step to assess and monitor the rutting, fatigue, low-temperature performance, durability, and chemical changes of binders during the aging process. The results of this study proved the enhanced properties and performances of the nanomodified binder compared to the unmodified binder. These results can pave the path with the use of nanomodified binders in the recycling of aged pavement and construction of roads that experience poor weather conditions and high traffic loads. [ABSTRACT FROM AUTHOR]

In hot mix asphalt concrete, bitumen is used as the adhesive and this material has a significant effect on the performance of mix asphalt. In order to improve the performance of the adhesive (bitumen), modifiers (additives) are used. In this study, gilsonite, as a part of bitumen and modifier, has been studied in order to improve the performance of mix asphalt. In this research, a nominal maximum size of 12.5 mm was chosen for the materials. In the first stage, in order to determine the optimum content for each component, three Marshall samples were produced and underwent Marshall tests. According to the Marshall test results, 5.9% was determined as the optimum bitumen content. In the second stage, samples from the optimum bitumen which were part of the gilsonite bitumen were produced and according to the test results, the sample containing 15% of gilsonite had the best performance. In the third stage, samples containing 0.5% more and 0.5% less amount of bitumen compared to the optimum bitumen content and 0%, 6%, 9%, 12%, 15% and 18% of gilsonite were produced and underwent the traditional Marshall and ultrasonic tests, where it was determined that the best performance belonged to the sample with 6.4% of bitumen and 15% of gilsonite. Also, in order to study the rutting of the mix asphalt containing gilsonite, samples with 0%, 6%, 12% and 18% gilsonite were produced and underwent dynamic creep test. The results showed that samples containing 12% and 18% of gilsonite had the least cumulative permanent strain and the highest stiffness modulus at 37.8°C and 54.4°C, respectively. [ABSTRACT FROM AUTHOR]

The use of molasses as a replacement for bitumen could benefit the pavement industry by improving the performance of the pavement or by lowering its cost. An experimental investigation was carried out to investigate the effect of molasses with different moisture contents on the property of hot-mix asphalt (HMA). Bitumen binders (BB) containing 5%, 10%, 15%, and 20% molasses were investigated as molasses modified binders (MMB). Molasses with 24.9% and 5.02% by weight of water were used to investigate the effect of moisture on the MMBs. In addition to the conventional binder tests, additional tests such as the Fourier transform infrared (FTIR) test, amplitude and frequency sweep test, performance grade (PG) test, and multiple stress creep recovery (MSCR) test were performed. The results indicated that most of the properties of the MMBs improved with the reduction in the moisture content of molasses but worsened with the percentage replacement of molasses. The IR spectra show that the carbonyl index decreased with an increasing amount of molasses. The control grade PG58 was improved to PG64 and PG70 when the base binder was modified with molasses and aged with rolling thin film oven (RTFO) consecutively. At a temperature of 58 °C, non-recoverable creep compliance of 3.2 kPa (Jnr3.2kPa) was decreased for each MMB, which leads to improved rutting potential. At a temperature of 64 °C, the Jnr value was decreased only for the MMB containing 5% molasses, and then gradually increased for the remaining MMBs. Generally, the study revealed that low moisture content molasses could be used as a partial replacement for bitumen to enhance the rheological properties of the bitumen.

This study is an investigation of the rheological properties of bituminous binders and the mechanical properties of hot mix asphalts (HMAs) when a combination of styrene-butadiene-styrene (SBS) and American Gilsonite (AG) is added to bitumen. In this work, HMAs were prepared with two binders containing a single additive (5% SBS and 18% AG) and three binders containing two different additives (4% SBS + 6% AG, 3%SBS + 10%AG, and 2% SBS + 13%AG), which have the same Superpave performance levels. Tests carried out on the mixes demonstrated that the most effective additives relative to Marshall stability, retained Marshall stability, and indirect tensile strength values were 18% AG and 3% SBS + 10% AG; the most effective additives relative to stiffness and fatigue life were 18% AG, 2% SBS + 13%AG, and 3% SBS + 10% AG; and the most effective additives against moisture-induced damage were 5% SBS, 2% SBS + 13%AG, and 3% SBS + 10% AG. A consideration of all of the study's findings indicate that the utilization of a combination of SBS and AG is provides more benefits than utilizations of SBS or AG alone. [ABSTRACT FROM AUTHOR]

In this experiment, at first, waste polyvinyl chloride was used as an additive in an attempt to improve the performance of bitumen and hot mix asphalt (HMA) in order to minimize the amount of rutting. To further these aims, conventional and rheological tests were conducted on bitumen and all HMA specimens were tested by Marshall stability, flow, and repeated load axial tests. After investigating rutting resistance of HMA samples, the results demonstrated that this waste material could improve the rheological properties of bitumen, and the HMA samples, manufactured by this particular type of bitumen, are more resistant to rutting. [ABSTRACT FROM AUTHOR]

The production of modified asphalt mixtures with appropriate performance in high temperature has always been under the attention of researchers. One of these modifiers is Styrene Butadiene Styrene (SBS) polymer. Since the application of SBS polymer in bitumen and asphalt mixture does not have expected performance of field due to phase separation of bitumen and polymer, oxidation, and aging, the present study tries to not only improve the polymer defects, but also analyzes its high-temperature performance by using nano-SiO2and SBS polymer in bitumen modification. According to the study results, adding nano-SiO2and SBS polymer with 3 and 4.5 bitumen weight percent, respectively, to bitumen in asphalt mixture leads to an increase of flow number in dynamic creep test at 50°C for 399 times and at 60°C for 1,015 times compared to unmodified asphalt mix. This, in turn, indicates the considerable improvement of asphalt mixture high-temperature performance. [ABSTRACT FROM AUTHOR]

One of the main reasons of premature damage to the asphalt layers of flexible pavements is the damage caused by moisture which is also called moisture damage or stripping. Stripping is defined as the loss of resistance and strength induced by moisture. Various methods have been used to decrease this type of damage using anti-stripping materials as the most common method. Problems associated with the practical application of anti-stripping materials coating aggregates and adverse effect of using bitumen-modifying additives have motivated us to investigate the effect of using styrene-butadienestyrene nano-composite as a new anti-stripping additive in hot-mix asphalt. In this study, besides applying modified Lottman test as a conventional test for moisture susceptibility, surface free energy methods were also utilized to determine the mechanism by which the considered nanomaterial affected cohesion and adhesion properties of asphalt mix components. Materials used in this study included two types of aggregates with different hydrophilic degrees (limestone and granite aggregates), bitumen with 60–70% penetration grade (PG 64-22), and SBS nano-composite with two different percentages. Results of the modified Lottman test showed that use of nano-composite improved the resistance of the asphalt mix manufactured by two types of aggregates used in this study. Also, the results of measuring surface free energy components of bitumen indicated that use of nano-composite increased the force required for producing the aggregate’s stripping in the bitumen, which further improved the strength of the asphalt mix against moisture damage. [ABSTRACT FROM AUTHOR]

Temperature is the main element in producing asphalt mixture for asphalt pavement. The presence of Evotherm 3G in the asphalt can help to reduce the temperature of asphalt production and hence reduce energy usage. This study presents the bitumen properties with Evotherm 3G and the effect of this additive on asphalt mixture performance in reducing production temperature compared to hot mix asphalt. The bitumen tests were performed on the bitumen penetration grade of 60/70 using the penetration, softening point, and viscosity tests, while the Marshall samples were produced for the asphalt properties evaluation. The results showed that asphalt containing Evotherm 3G produced at a lower compaction temperature has comparable stability and flow to the conventional hot mix asphalt. The viscosity data of the bitumen added with Evotherm 3G does not give a significant difference compared to the penetration value. This justifies the applicability of Evotherm 3G as a surfactant in warm mix asphalt production. • Evotherm 3G reduces the asphalt production temperature. • Evotherm 3G works as a surfactant and does not change the bitumen properties. • WMA with Evotherm 3G has comparable Marshall properties to HMA. [ABSTRACT FROM AUTHOR]

[Display omitted] • EAFS shape properties have an effect on aggregate-bitumen adhesion. • The aggregate-bitumen bond is affected by physical–chemical, morphological and mineralogical properties. • EAFS have a higher affinity with bitumen than granitic and limestone aggregates. • EAF-Slags' complete and partial replacement of natural aggregates has positive effects on the mechanical properties of hot mix asphalt (HMA). • EAFS can improve resistance to moisture damage due to positive aspects of internal factors. Electric arc furnace slag (EAFS) has been proposed as a replacement in hot-mix asphalt. This work compares the physical–chemical-mineralogical and morphological factors involved in the moisture damage of natural aggregates and EAFS. Digital image analysis, aggregate-bitumen affinity based on 3 methods, and evaluation of water sensitivity (by indirect tensile strength ratio ITSR) tests were made. Findings showed that the sample with natural aggregates has an ITSR of 92%, and the samples with EAFS-replacement (coarse fraction) and with total EAFS-replacement exhibit 98% and 100% respectively. Our results suggest that EAFS can improve resistance to moisture damage due to positive aspects of internal factors. [ABSTRACT FROM AUTHOR]

Flexible asphalt pavement construction is an expensive investment. Nowadays, many methods are being investigated to improve the performance of asphalt mixtures. For this reason, bitumen is usually used with modified form in hot mix asphalt (HMA) in practice. The use of recycled waste materials as modifier additives on bitumen could have several economic and environmental benefits. The main aim of this research was to investigate the effect of HDPE (High density Polyethylene) based plastic waste materials on the performance of asphalt mixtures. For this purpose, HDPE based waste materials were added to the bitumen as modifier in to amount of 1%, 2%, 3%, 4%, then asphalt mixtures formed by the modified bitumen were tested for the determine their performances. The performance of specimens was firstly measured by stability, flow values. Then, susceptibility characteristics of the HMA to water damage were determined by using Indirect Tensile Test (ITT) method described in AASHTO T283 with classically compacted specimens. The results showed that, the best performance was obtained with a content 4% in terms of stability values. In addition, all specimens were showed resistance to water damage. [ABSTRACT FROM AUTHOR]

The research aims at evaluating the effect of using recycled coarse concrete aggregates (RCA) on the basic properties of hot mix asphalt made with different grades of bitumen (60/70 and 80/100). First, recycled aggregate properties have been determined and compared to those of normal aggregates. Except for absorption, there were no significant differences between normal aggregates and RCA. Later, recycled aggregates were introduced in asphalt mixes using either 60/70 bitumen or 80/100 bitumen. In these mixes, natural coarse aggregate was partly (0%, 25%, 50% and 75%) or totally (100%) replaced by recycled aggregates. Replacement results show that the use of recycled aggregates increased the optimum bitumen content of the asphalt mixes. Properties and performance of mixes made from both grades of bitumen were compared. Although the increase of RCA percentage decreased the resilient modulus of the asphalt mixes, it increased their skid resistance. However, 60/70 bitumen increased the resilient modulus and skid resistance of the asphalt mixes compared to 80/100 bitumen. Mixes containing RCA show lower water sensitivity (stripping resistance) than RCA-free mixes. However, replacements up to 50% do not violate the 80% tensile strength ratio limit. Although the 50% replacement limit is acceptable, however, the volumetric properties were violated at this replacement ratio. Therefore, for both grades of bitumen, replacements more than 25% should not be used in hot mix asphalt for heavy traffic pavements. [ABSTRACT FROM AUTHOR]

In this study, utility of polyparaphenylene terephtalamide (PT) was investigated in hot mix asphalt as a fiber. For this aim samples were prepared with limestone aggregate at different proportions. Marshall Stability test was applied and optimum bitumen content was determined. In the second stage of the study, new samples were prepared using different polyparaphenylene terephtalamide fiber (PTF) rates of 0.25%, 0.50%, 0.75%, 1.00%, 1.50%, 2.00% based on optimum bitumen content. When examining test results, samples which prepared using 0.25% PTF rate gave highest Marshall Stability result. At the final stage of the study, different bitumen contents (4.15%, 4.65% and 5.15%) were conducted for the best fiber rate (0.25%) and close to this result (0.50% and 0.75%). Thus, the effect of bitumen content on determined fiber rate at the second stage of the study was investigated. Also Indirect Tensile (IDT) Strength Test was performed on hot mix asphalt (HMA) samples preparing at 0.25%, 0.50% and 0.75% fiber rates and moisture sensitivities were determined. All results showed that, the best fiber rate was 0.25% and determined optimum bitumen content remain constant with the fiber additive for the reference samples. Besides, some sample groups which prepared using different PTF rates proved the specification limits and it was said that; PTF can be used in asphalt concrete as a fiber additive. [ABSTRACT FROM AUTHOR]

Several waste and used materials from different sources are generated every day in large quantities. However, these wastes have been found to be useful in the stabilization and/or improvement of construction materials. Amongst these techniques is the use of Bagasse Ash (BA). It is in this light that a laboratory based investigation for the replacement of cement with BA in Hot Mix Asphalt (HMA) was conducted. Tests on the suitability of materials used and their performance in terms of known engineering properties was carried out. Bitumen content of 4.5%, 5.5%, 6.5% and 7.5% was adopted. The focus involves the partial replacement of cement with BA in the following order, 0% (control), 10%, 20%, 30%, 40% and 50%. Seventy-two mix specimens were produced. The results obtained shows that the Cement/BA mixes exhibit satisfactory trend result with an average bitumen content of 5.5%.The results obtained shows that stability increases as BA content decreases, flows at 5.5% bitumen Content was observed to be fairly constant at roughly 2.5mm, the per cent air voids in the mix decreases with increasing bitumen content, the VMA values all fall within specification except for 30% BA replacement, the VMA value was 16% at 5.5% of Bitumen Content. Therefore, the Cement/BA mixes exhibit satisfactory trend results with an average Bitumen content of 5.5%. [ABSTRACT FROM AUTHOR]

Stripping – the most important mode of Hot Mix Asphalt (HMA) failure – is a problematic issue in the pavement performance and its maintenance. Identification and quantification of the pertinent parameters influencing on stripping process is a prerequisite for dealing with it effectively. Previous studies on stripping potential of HMA have focused on this issue based on empirical/semi-empirical models. In the present work Response Surface Methodology (RSM) was used for the study and optimization of pertinent factors, namely bitumen content employed, grading and lime content, in the stripping process of HMA. Tensile Strength Ratio (TSR) was chosen as the response for the evaluation of stripping potential of HMA using a Central Composite Design (CCD). The statistical analyses showed that second order polynomial models can successfully describe the relationship between the response and factors and the maximum Tensile Strength Ratio (TSR) is achieved at 5.73% bitumen content, 1.84% lime content and 65.30% of the materials passing sieve size 4.75 mm. [ABSTRACT FROM AUTHOR]

Metakaolin is one mineral admixture that appears to have significant potential for the production of high strength and high performance concretes. This work investigates the performance of asphalt concrete containing Metakaolin partially replaced with cement. Oxide composition test on Metakaolin, tests on aggregates and cement, bitumen tests (consistency test) were carried out. Several mix containing different percentages of Metakaolin and ordinary Portland Cement was prepared to evaluate its strength using Marshall Stability Method of pavement design. It was found that at varying percentages of bitumen content, the stability, flow, voids in mixed aggregates and void in the mix meets the standard specified with an optimum bitumen content of 5.5%. [ABSTRACT FROM AUTHOR]

Highlights: [•] Steel slag aggregates improved the Marshall stability of hot mix asphalt mixtures. [•] Moisture susceptibility of warm mixtures containing steel slag was improved. [•] Warm mix asphalt mixtures containing steel slag aggregates showed higher resilient modulus. [•] Steel slag aggregates improved resistance to permanent deformation in warm mixtures. [Copyright &y& Elsevier]

Highlights: [•] In this study, the usability of rice husk ash was investigated in hot mix asphalt concrete as mineral filler. [•] Optimum bitumen content was determined as 4.73% for 5.0% limestone mineral filler rate. [•] Best Marshall Stability was obtained from 50% rice husk ash and 50% limestone of filler rate mixtures. [ABSTRACT FROM AUTHOR]

In this study, the aim was to determine the influence of asphaltite addition on the stiffness of the hot mix asphalts as well as on their resistance against fatigue and permanent deformation through cyclic tests. The asphaltite was included as filler into the hot mix asphalt specimens at five different proportions. The cyclic tests were performed on both the short-term aged and the long-term aged specimens. The study demonstrates that the optimal asphaltite content for utilization as filler with respect to volumetric design is 3% by weight. It was inferred from the results of indirect tensile stiffness modulus test that asphaltite increases the stiffness of hot mix asphalts. Similarly, the indirect tensile fatigue tests demonstrate that the use of asphaltite improves the fatigue life of the hot mix asphalts, albeit causing them to exhibit a more brittle behavior. The cyclic creep tests conducted on the specimens point out that the strength against permanent deformation increases by prolonged aging durationş and the mixtures display less elastic behavior with the use of asphaltite. [ABSTRACT FROM AUTHOR]

This study was conducted to evaluate the rutting and moisture damage distresses which are the two major concerns in warm mix asphalt (WMA) performance. Two different methods were used to produce WMA mixes using foam bitumen technology. In the first method, the samples were prepared by transforming total bitumen of the mix into foam bitumen, whereas in the second method, two bitumens (soft and hard), the latter in foaming state, were added to the mix resulting in the same bitumen penetration in the final cured samples. The results of testing indicated that lowering the mixing and compaction temperatures resulted in increased moisture susceptibility and rutting potential of both WMA foam mixes. The Marshall quotient values and wheel tracking test results showed that the rutting potential of the WMA foam mixes were significantly greater than the control hot mix asphalt. The addition of hydrated lime powder was found to be effective in decreasing rutting and moisture susceptibility of the WMA foam mixes. [ABSTRACT FROM AUTHOR]

Road pavements are pivotal to the infrastructure, transportation and ultimate efficiency of both the public and the economy. However, they are undeniably having detrimental effects on an already compromised environment. Consequently, a re-think about road pavement construction materials is of paramount importance. Cold mix asphalt (CMA) is a low carbon manufacturing approach to the production of flexible pavement material that has proved to be very promising, both economically and ecologically. This technology allows the manufacture of mixtures at ambient temperatures without heating huge amounts of aggregates and bitumen, this decreasing CO 2 emissions and saving energy. In spite of these positive impacts, CMA has a high sensitivity to traffic and environmental stresses due to the existence of water within the mixture, this of major concern to the industry. This study aims to review types of CMA and the main developments involved in cold bitumen emulsion mixture (CBEM) technology that can be used without decreasing in-service performance. This review also aims to provide a practical guide for the manufacture of bitumen emulsion and the design procedure of CBEM for the road pavements industry. Finally, it can be suggested that CMA is a crucial technique for pavement construction, as it provides acceptable performance alongside energy-saving and ecological objectives. • CBEMs have several ecological and economic benefits. • Laboratory data show an equal or better performance of CBEM compared to HMA. • The laboratory behaviour investigations on CBEM are not conclusive. • The application of waste materials in CMA improves sustainability. [ABSTRACT FROM AUTHOR]

This study investigated the viability of quantifying the affinity between aggregate and bitumen by means of different imaging techniques. Experiments were arranged in accordance with the rolling-bottle test, as indicated in UNI EN 12697-11, "Test methods for hot bituminous conglomerates—Part 11". Digital image processing (DIP) techniques have only recently been used for such quantification. The data gathered with a multi-sensor optical platform equipped with VIS–NIR and SWIR spectrometers were compared with DIP outcomes. Data were processed using the unsupervised ISODATA and the supervised parallelepiped algorithms. The exposed aggregate index (EAI) and the bitumen index (BIT) were calculated to retrieve the bitumen percentage coverage of different mixtures. The comparison with the results obtained employing the traditional 6, 24, 48 and 72 testing hours reveals the possibility to implement a standardized analysis methodology combining digital and hyperspectral imagery to highlight potential inaccuracies deriving from the visual interpretation. [ABSTRACT FROM AUTHOR]

• Previously used methods for determining DoA, DoAv and DoB are shown. • Investigation methods for determining DoA, DoAv and DoB are classified. • Advantages and disadvantages of the investigation methods and techniques are shown. • The literature review which may help in quantifying DoA, DoAv and DoB is given. The lack of understanding the mechanisms governing the interaction between reclaimed asphalt binder (RAb) 1 1 RAb – Reclaimed Asphalt binder. and recycling agents is one of the technical issues that still need to be resolved when high amount of reclaimed asphalt (RA) 2 2 RA – Reclaimed Asphalt. is used in a new recycled asphalt mixture (RAM). Due to important role of RAb in that interaction and increased used of RA, it becomes necessary to have a way to classify RA, as any other material used in asphalt mixture production. It is very important to determine how much RAb is active by itself (DoA) 3 3 DoA – Degree of binder Activity. , but also to determine how much RAb can be considered available for a mix design of RAM (DoAv) 4 4 DoAv – Degree of binder Availability. when a recycling agent is used. Finally, since that RAM's properties are strongly dependent on the degree of blending between RAb and recycling agent (DoB) 5 5 DoB – Degree of Blending. , it should evaluate to what extent RAb contributes to the final properties of RAM. These blending parameters (DoA, DoAv and DoB) are so crucial that identifying suitable methodologies for their assessment would be extremely important in performing a proper mix design due to dangerous of having a lack of active bitumen in RAM. This paper presents a literature review of methods which have been used for the evaluation and assessment of mentioned parameters, grouped in four macro-areas: mechanical, chemical, visualization and mechanistic approaches. Furthermore, summarized review of used methods was prepared together with their critical review, all with aim to find appropriate methods for determining these parameters. [ABSTRACT FROM AUTHOR]

• 100% recycling of RAP binder using RA was used. • A procedure to select a proper RA type based on RAP binder properties was developed. • Aging rate, rutting, fatigue, low-temperature performance, carbonyl, and sulfoxide functional group of binder were considered. • The FTIR test can be substituted to the rheological tests of asphalt to predict asphalt performance in during its service life. The incorporation of reclaimed asphalt pavement (RAP) in the construction of new asphalt pavement is limited due to issues with the short-term and long-term performance of pavement. To enhance the aged binder properties, recycling agents (RAs) are added to RAP mixtures. There are different RAs available, and they impact the asphalt binder properties differently, resulting in various aging rates of recycled asphalt. Therefore, in this study, the rheological and chemical characteristics of 100% recycled asphalt binder using different RAs were investigated using Dynamic Shear Rheometer (DSR), Bending Beam Rheometer (BBR), and Fourier-Transform Infrared Spectroscopy – Attenuated Total Reflection (FTIR-ATR). The Rolling Thin-Film Oven (RTFO) and Pressure Aging Vessel (PAV) were used to simulate the short-term and long-term aging of asphalt binder, respectively. The long-term aging of the binder was simulated by aging asphalt binder with two PAV cycles. This study aims to identify the proper RA for the recycling of binders according to the aging rate, and the short- and long-term performance of recycled asphalt binder. The results show that the recycled binders with a specific RA that have the minimum initial concentration of sulfoxide and carbonyl could provide better performance in compared to recycled binders with other RAs. This result can be used to predict the long-term performance of recycled asphalt, in addition to identifying the proper RA in the recycling process of asphalt pavement. [ABSTRACT FROM AUTHOR]