Weight Of Asphalt Research Articles

THE PHYSICAL AND RHEOLOGICAL CHARACTERISTICS OF MODIFIED ASPHALT BINDER WITH TITANIUM DIOXIDE R15

The objectives of this study include determine the physical and rheological properties of the modified asphalt and also to examine the effectiveness of TiO2 in lowering the viscosity of the asphalt compared to control asphalt. Nano-titanium dioxide R15 of 2%, 4%, 6%, 8% and 10% by weight of asphalt has been incorporated into unaged 80/100 asphalt mix in order to improvise its performance. The asphalt modified and control were examine using penetration test, softening point test, storage stability test, dynamic shear rheometer test (DSR), rotational viscosity (RV) and rolling thin film oven test (RTFO). As a conclusion, the decrease in compaction and mixing temperature of modified asphalt compared to original asphalt shows an improvement in the viscosity of the asphalt. Through DSR, the nano-TiO2 modified asphalt does not degrade the performance grade when compared to control asphalt, where the values of complex modulus, G* does not differ much from each other for each of the concentration. This indicates that the modified asphalt is as competent as the original binder in resisting rutting at high temperature.

RHEOLOGICAL BEHAVIOUR OF COCONUT SHELL POWDER MODIFIED ASPHALT BINDER

The objectives of this study were to determine the blending parameters of coconut shell powder (CSP) modified asphalt binder and to evaluate the rheological properties of CSP modified asphalt binder. CSP of 2%, 4%, 6%, 8% and 10% by weight of asphalt have been incorporated into an unaged 80/100 asphalt mix in order to improve its performance. The influence of the additives on the physical and rheological properties was evaluated with penetration test, softening point, storage stability, dynamic shear rheometer test (DSR), and Field Emission Scanning Electron Microscope (FESEM). The aging of asphalt binders was simulated in a laboratory by using Rotational Thin Film Oven (RTFO). The results showed that the addition of CSP into virgin binder was decreasing the penetration value and increasing the softening point temperature compared to the original binder. On the rheological effect, for unaged modified binder, higher CSP resulted higher G*/sin δ especially at lower temperature compared to the unaged control binder. Besides, for the aged modified binder, stiffness was lower than the control aged binder for all temperature.

Laboratory evaluation of asphalt binder modified with carbon nanotubes for Egyptian climate

This paper mainly aims at investigating the effect of using multi-wall carbon nanotubes (MWCNTs) as an additive on the rheological properties of asphalt. Pristine (P-MWCNTs) were mixed at 120°C with control asphalt at contents of 0.5%, 1.0%, 2.0% and 3.0% by asphalt weight. The empirical and rheological properties (using the Superpave testing) of the control and modified asphalts were evaluated at different aging conditions. The rheological properties of the modified asphalts were found to improve with increasing the percentage of P-MWCNTs. The high failure temperature and rutting resistance of both unaged and rolling thin film oven aged (RTFO) modified asphalts increased with increasing P-MWCNTs percentage and became suitable for the Egyptian climatic conditions as required by the Superpave binder characterization. At a given temperature, the fatigue cracking resistance and low temperature cracking resistance decreased with increasing P-MWCNTs percentage.

Effect of Functionalization and Mixing Process on the Rheological Properties of Asphalt Modified with Carbon Nanotubes

The aim of this paper is to investigate the rheological properties of conventional asphalt modified with Multi- Walled Carbon Nano Tubes (MWCNTs). Pristine MWCNTs were chemically modified using acid functionalization process to introduce carboxylic acid groups onto the surface of MWCNTs. The pristine and functionalized MWCNTs were then characterized by Scanning Electron Microscope (SEM) and electron dispersion X-ray (EDX) analysis. A 3% (by weight of asphalt) of pristine and functionalized MWCNTs were each blended with a base asphalt at 120°C. The properties of the base and modified asphalts were evaluated using softening point, rotational viscometer and dynamic shear rheometer (DSR) for both original and short term aged asphalts using the rolling this film oven (RTFO) test. The results indicated that the use of MWCNTs as a modifier was helpful in improving the conventional and rheological properties of the asphalt. Generally, it was found that the softening point, as well as the rotational viscosity, were increased and the temperature susceptibility was improved. The results showed a remarkable improvement in the binder complex shear modulus, failure temperature, and rutting resistance. The rheological properties of the asphalt modified with pristine MWCNTs were better than the functionalized MWCNTs. Finally, the effect of mixing technique (high shear mixer and a manufactured mechanical mixer) of MWCNTs with asphalt was evaluated. Results showed that both mixers yielded similar properties based on the rotational viscosity testing.

Rheological Properties of Polypropylene Reinforced Asphalt Binder

Polypropylene fibers (PP fibers) were used as additives to prepare fiber-reinforced asphalt binders in this work, with concentrations varying from 0 to 2.5 % in increments of 0.5 % by weight of asphalt. The microstructure of fibers and dispersion of fibers in the asphalt were analyzed via scanning electron microscopy (SEM) using a ZEISS microscope at different magnification rates. Penetration, softening point, dynamic shear rheometer (DSR), and Multiple Stress Creep Recovery (MSCR) tests were conducted to study the rheological properties and the results are compared. With the increase in the dosage of PP fibers, the penetration values were decreased while the softening points increased. Complex shear modulus was increased and phase angles were decreased. The Strategic Highway Research Program (SHRP) rutting parameter G*/Sinδ and the Shenoy’s rutting parameter, G*/(1 − (1/sinδ.tanδ)), were improved with fibers. MSCR results indicate that the non-recoverable creep compliance (Jnr) and percent of recovery (R%) are decreased and increased, respectively, with the addition of fibers. The results indicate that the asphalt with PP fiber reduces thermal sensitivity and increased resistance to permanent deformation at high temperatures. The Shenoy’s rutting parameter has better correlation with non-recoverable creep compliance (Jnr) and it can be considered as a better rutting predictor than G*/Sinδ for fiber modified asphalt binders.

Rheological Evaluation of Asphalt Cements Modified with ASA Polymer and Al2O3 Nanoparticles

This study aims to evaluate and characterize the properties of modified asphalt cements exposed to high temperature. The Acrylate Styrene Acrylonhrtilrei (ASA) polymer and nano aluminum oxide (Al2O3) nanoparticles were added to the base asphalt cement with concentrations of 3, 5 and 7% of the weight of asphalt. The storage stability, viscosity, frequency sweep and MSRC test were considered for evaluation. The results demonstrate that the addition of ASA polymer and Al2O3 nanoparticles content have a great influence on the rheological properties of the asphalt cement at high temperatures. Additionally, it is clear that the storage stability of modified asphalt cements with ASA polymer and Al2O3 nanoparticles has good compatibility among the asphalt cement and the modifiers. Moreover, the complex modulus (G*) improves as the concentration of both modifiers increases. The improvement was 63.70% for 5% ASA polymer, and 71.12% for 5% Al2O3 at 75°C. Moreover, the modified asphalt cements demonstrates great resistance to high temperatures rutting, as the enhancement was up to 80 and 59% for 5% concentration of ASA and Al2O3. The modification of asphalt cements provides increasing the creep recovery up to 69.23 and 62.53%. It was found that the usage of ASA polymer and Al2O3 nanoparticles is able to mitigate asphalt cement problems at high temperatures, and 5% is considered as the optimum content of both modifiers.

Effect of Used Motor Oil on the Macro and Micromechanical Properties of Crumb Rubber Modified Asphalt

The need to be more environmentally conscious has recently shifted toward the forefront of society. With this new focus on environmentally responsible behavior comes the practice of using recycled materials in construction when possible. Used motor oil (UMO) is an example of waste materials that can be utilized in numerous applications to alleviate its environmental disposal burden. In the current work, the effect of UMO on the internal structure of crumb rubber modified asphalt is investigated. This is carried out by employing rheological analysis including dynamic shear rheometer and microindentation testing. Rheological analysis was employed to determine the change in the phase angle (δ) as well as the complex modulus (G*) of the UMO modified asphalts as well as the crumb rubber modified asphalt (CRMA), in addition, temperature sweep viscoelastic analysis was employed to investigate the change in internal structure of the produced modified asphalts. Microindentation analysis was utilized to determine the hardness and elastic modulus of the modified asphalt liquid phase. Microindentation tests served to simulate the effect of UMO on the behavior of the thin asphalt layer over the aggregate which has a thickness measured in microns. Results indicate that the utilization of UMO only as a modifier to asphalt severely deteriorates the macro and micro mechanical properties of the binder. Combining CRM with UMO as modifiers to asphalt had better results. It is suggested to use UMO at a rate of 3%, or less, by asphalt weight.

Use of Ash in Hot Dense Mixtures

Bituminous ash produced by the oil industry is used in landfill in large quantities. Recycling ashes coming from the oil industry can have signifi-cant benefits for the environment and is an attractive option for highway construction because it saves material acquisition and disposal costs. An experimental study was undertaken to investigate the use of these ashes as a replacement for mineral filler in hot-mix asphalt concrete. Physical tests were performed on the bituminous ash to determine its gradation, specific gravity, and chemical composition. Two cases were considered for determining the ash proportion. To evaluate the effect of a reduction in asphalt binder, ash with a maximum particle size of 0.074 mm [i.e., passing the Number (No.) 200 sieve] was used as a replacement for the asphalt cement content at percentages of 0 (i.e., control mix), 5, 10, and 15 by total asphalt weight. Also, ash was used as a replacement of the fine aggregate at percentages of 0, 30, 50, and 70 by total aggregate weight. In both cases, the ash came from thermal desorption in the hydrocarbon processes. Mix design was accomplished according to the Marshall mix design method (ASTM D1559). The results of these studies showed that use of ash passing the No. 4 sieve improved asphalt concrete characteristics while it reduced the use of aggregates when the asphalt proportion was 4.5%. Likewise, use of 0.8% fine ash (i.e., finer than the No. 200 sieve) to reduce the asphalt content in the hot dense mixture also improved the performance of asphalt concrete.

Performance Evaluation of Polymer Modified Asphalt Mixtures

Attention has been increasing towards the use of polymer modified asphalt, because conventional asphalt mixtures cannot resist the high axle loads and tire pressures. Several classes of modified binders have been used in asphalt pavements. The main objective of this research was to evaluate the effect of adding several types of polymers on asphalt cement and asphalt mixtures. Experimental program involved two phases. The first phase was modifying the asphalt using six types of polymers then evaluating the properties of the modified asphalt. The second phase was evaluating the effect of binder modification on Marshall mix design and indirect tensile strength of the asphalt concrete mixtures. It was found that the optimum percentage of PVC, plastic bags and novolac was 4%, and the optimum percentage of HDPE was 5% by weight of asphalt. These percentages caused increase in kinematic viscosity, stability, and indirect tensile strength and caused reduction in penetration.

A STUDY ON MARSHALL PROPERTIES FOR POLYMER MODIFIED BITUMEN IN DIFFFERENT MOLAR RATIOS

Polymer modified asphalt is increasingly used in road surfacing. Unmodified asphalt is sensitive to changes in temperature, it becomes brittle and cracks in cold weather and soften in high temperature, causing rutting and surface deformation. This research aims to prepare hot mix asphalt (HMA) for paving using polymer prepared from stearyl acrylate and methyl methacrylate and styrene in molar ratios: 0.5:0.5:0.2 and 0.5:0.5:0.5, respectively. The solid materials in the mix include normal and highly porous aggregates. 4,6,8% of two polymers by weight of asphalt were used to prepare special binders. The samples were tested for physical, chemical, ageing, SEM and TGA. The results revealed that the prepared hot mix asphalt (HMA) polymer had high performance as compared to ordinary one and the two polymer prepared could be used in road construction.

Effect of Using Polymers on Bituminous Mixtures Characteristics in Egypt

Attention has been increasing towards the use of polymer modified asphalt, because conventional asphalt mixtures cannot resist the high axle loads and tire pressures. Several classes of modified binders have been used in asphalt pavements. The main objective of this research was to evaluate the effect of adding several types of polymers on asphalt cement and asphalt concrete mixtures. Experimental program involved two phases. The first phase was modifying the asphalt using six types of polymers then evaluating the properties of the modified asphalt. The second phase was evaluating the effect of binder modification on Marshall mix design characteristics and indirect tensile strength of the asphalt concrete mixtures. It was found that the optimum percentage of PVC, plastic bags and novolac was 4%, and the optimum percentage of HDPE was 5% by weight of asphalt. These percentages caused increase in kinematic viscosity, stability, and indirect tensile strength and caused reduction in penetration.

Investigation of the rheological modification mechanism of crumb rubber modified asphalt (CRMA) containing TOR additive

Crumb rubber obtained from scrap tires has been incorporated with asphalt binder to improve the performance of asphalt mixtures in the past decades. However, rubber asphalt mixtures demand higher production temperatures than conventional asphalt binders due to the higher viscosity of asphalt rubber binder. The objective of this paper is to evaluate the rheological properties of crumb rubber modified asphalt by adding trans-polyoctenamer rubber (TOR) additives and investigate the modification mechanism between TOR and crumb rubber modified asphalt. In this study, CRMA was prepared by mixing Karamay 70 penetration grade base asphalt at 15%, 20% and 25% crumb rubber proportions by weight of asphalt. TOR, a typical reactive modifier, was added to CRMA at two percentages of 0% and 4.5%, respectively. Several conventional laboratory rheological tests were carried out to evaluate the performance of CRMA with and without TOR additive at different temperatures. Furthermore, in order to investigate the interaction mechanism of TOR and CRMA, a series of advanced tools, including the scanning electron microscopy (SEM) test, differential scanning calorimeter (DSC) test, Fourier transform infrared spectroscopy (FTIR) test were conducted. From the experimental results obtained, it may be concluded that CRMA with adding TOR not only improves the engineering properties of the rubber modified asphalt, but also improves the performance of asphalt rubber. From the microscopic tests, it is concluded that there is a complex chemical reaction between TOR and CRMA, which changes the rheological properties of CRAM and contributes to the storage stability of asphalt binder.

Study on Asphalt Absorption of Steel Slag

Steel slag has been using as a substitution of natural aggregate, such as basalt and limestone, in road construction. But the huge asphalt absorption of slag has been a main obstacle to hinder the utilization of slag. But the detailed study in this area is still less. This paper investigated the asphalt absorption characteristic of steel slag. The results suggest that: the value of asphalt absorption of steel slag (AAOS, the weight of asphalt absorbed by per 100g steel slag) is much higher than the ones of limestone or basalt; AAOS increase slowly with the prolongation of storage time or the increase of storage temperature; the increase of viscosity causes a drastic reduction of asphalt absorption. The results also reveal that with the increase of asphalt content the AAOS value firstly increases and then decreases.

PERFORMANCE ENHANCEMENT OF ASPHALT PAVEMENT

Age hardening of paving grade asphalt is a major factor affecting the durability of bitumen pavement. In this research, 60/70 penetration grade asphalt is modified using Styrene Butadiene Rubber(SBR) in percentages by weight of asphalt ranging from 2 to 6% and 1% by weight of asphalt of an antioxidant namely 4.4. thio bis (6- tertiary butyl – m – cresol (TBMTBP). The antioxidant is used to delay the age hardening . Hot mixes asphalt using the virgin and modified asphalt samples are prepared and evaluated using Marshall test method . Fourier Transform Infra Red (FTIR) is used to analyze all samples of asphaltic materials. The results reveled that, the polymer increased the performance of hot mix and the antioxidant delayed the formation of carbonyl group which is formed as a result of asphalt aging. So, this type of modification is considered as an attractive solution for increasing the performance and the service lifetime of asphalt mix .

Investigation of the Rheological Modification Mechanism of Warm-Mix Additives on Crumb-Rubber-Modified Asphalt

Studies in recent years have proved that warm-mix asphalt (WMA) additives can effectively improve the rheological properties of crumb-rubber-modified asphalt (CRMA) without significantly affecting its engineering properties. However, limited research has been done to investigate the rheological modification mechanism of WMA additives on CRMA. In this study, CRMA was prepared by mixing PG64-22 asphalt with 18% crumb rubber by weight of asphalt. Evotherm-DAT, a typical WMA additive, was added to CRMA at four percentages: 0, 8, 10, and 12%. Various conventional rheological tests were performed to evaluate the performances of the CRMA with and without Evotherm-DAT additives at different temperatures. In addition, a series of unconventional tests; including environmental scanning electron microscopy (ESEM), chemical composition, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and nuclear magnetic resonance (NMR) spectroscopy; were conducted to investigate the interaction mechanism of Evotherm-DAT and CRMA from the viewpoints of thermal effects, microscopic morphology, chemical composition, and molecular structure. This study concluded that there is no complex chemical reaction between Evotherm-DAT and CRMA. However, Evotherm-DAT affects the state of aggregation of the crumb rubber and the intermolecular forces of CRMA, which in turn changes the rheological properties of CRMA.

Pengaruh Penambahan Plastik High Density Polyetilene (HDPE) dalam Campuran Hot Rolled Sheet Wearing Course (HRS-WC) terhadap Parameter Marshall, Kuat Tekan dan Kuat Tarik Belah

In this study, plastics High-Density Polyethylene (HDPE) were used as an additional ingredient of asphalt for HRS-WC mixtures by using a variation of the plastic content of 0%, 2%, 4%, 6% to the asphalt weight. Bitumen content obtained from the optimum bitumen content of 7.5%. The purpose of this research is to examine and to compare the Marshall characteristics, compressive strength and split tensile of HRS-WC mixture. The results showed that the addition of HDPE plastic provide a significant influence on the marshall characteristic, split tensile strength and compressive strength. Asphalt stability with the addition of HDPE by 2%, 4% and 6% compliant with the specifications of marshall stability results respectively amounted to 2589.40 kg, 2257.13 kg and 2385.16 kg.

Effects of Type and Content of Mineral Fillers on the Consistency Properties of Asphalt Mastic

Abstract Although commercial mineral fillers have become mandatory for use in asphalt concrete mixtures by many highway agencies, the consequences of such additives have shown a great effect on the consistency properties of asphalt mastic as compared to the neat asphalt binders. A detailed analysis as to whether neat asphalt binders or asphalt mastic should provide pertinent information for material characterization and construction indices for asphalt mixtures is presented. Laboratory experiments were conducted to investigate the effects of type and content of mineral fillers on the consistency properties of asphalt mastic to the neat asphalt binder designed to meet the JTG F40-2004 specification of China. Three different mineral fillers, namely hydrated lime, pulverized limestone, and Portland cement were separately dry mixed with neat asphalt binder at dust to binder ratios ranging from 0.0 to 1.5 in ratio increments of 0.3 % by weight of asphalt. Analysis of test results shows that asphalt mastic consistency properties are well-defined linear functions of mineral filler content. Hydrated lime mastics showed significant effects on the consistency properties of the neat binder as compared to Portland cement and limestone additives tested at the same mineral filler content. Penetration and ductility of the neat binder showed a linear reduction at increased hydrated lime content estimated at 4.8(0.1 mm) and 8.2 cm per 0.1 % of hydrated lime increment respectively while softening point and apparent viscosity increased at the rate of 4.7°C and 0.1 centipoises per 0.1 % of hydrated lime increment respectively. Asphalt mixtures mixing and compaction temperatures determined from equiviscous lines of 0.17±0.02 Pa·s and 0.280±0.03 Pa·s using hydrated lime mastics show a linear increment of 7.7°C and 7.9°C per 0.1 % increment of hydrated lime respectively.

Laboratory evaluation on the high temperature rheological properties of rubber asphalt: a preliminary study

Crumb rubber is the recycled rubber particle obtained from mechanical shearing or grinding scrap tires into small particle sizes less than 6.3 mm (or approximately 1/4”). The rheological properties of asphalt binder have an important effect on the field performance of asphalt mixtures and the long-term serviceability of asphalt pavement. The objective of this research is to evaluate the high temperature rheological performance of rubber asphalt binder based on the complex shear modulus (|G*|) and the phase angle (δ) values using the dynamic shear rheometer. Five rubber asphalt dosages at 0, 10, 15, 20, and 25% by weight of asphalt (Superpave PG 64-22), respectively, were used to modify asphalt binder; and three rubber particle meshes, 20#, 30#, and 40#, were utilized in this research. The |G*| at various temperatures and frequencies were tested on each sample, including original and short-term aging binder using the rolling thin-film over. The master curves of |G*|/sin(δ) for each type of rubber asphalt was generated to investigate its rheological properties over a broad range of temperatures and frequencies. Based on the testing results, it was found that the addition of crumb rubber significantly increases the |G*| of asphalt binder, which is desirable to potentially improve the anti-rutting performance of asphalt mixtures. It was also found that the addition of 10% mesh crumb rubbers bumps up the high temperature grade of asphalt, from PG64 to PG76 in this case. The master curve using the |G*|/sin(δ) of rubber asphalt shows a substantial improvement in rutting resistant at each testing temperature and loading frequency. However, it was noteworthy that the rutting resistance enhancement of crumb rubber was affected by the percentage of rubber used, the rubber particle size and its aging condition.

Rheological properties of asphalt modified by supramolecular UV resistant material-LDHs

Dynamic rheological properties of asphalt modified by Supramolecular UV resistant material—layered double hydroxides(LDHs) was studied by means of the dynamic shear rheometer (DSR) test. Two typical base asphalts were chosen and modifi ed by 2 different LDHs contents. DSR tests were performed on the original samples, samples after exposed to outdoor and samples after the artifi cial accelerated UV aging tests respectively to analyze the rheological properties. It is found that when the LDHs content is between 3wt% and 5wt% of asphalt weight, the high temperature performance and fatigue resistant property of the modifi ed asphalt become better, the UV aging resistance properties are improved.

An in situ method for translation of acid sludge to modified asphalt paving materials

The acid sludge, which was obtained from the recovery of used oil, was disposed through an in situ mixing with styrene–butadiene–styrene (SBS) modifier during its neutralization reaction to afford an usable road paving material. Different contents of SBS (1.0%, 2.0%, 4.0%, and 6.0% by weight of asphalt) were blended, respectively, with an contrast industrial 70/100 paving grade asphalt and the neutralizing sludge binder. Unmodified (0% SBS), modified sludge asphalt (SBA), and industrial binders (IB) were subjected to the tests of physicochemical, tensile, toughness, and storage-stability. The analyses of test results show that the tensile and toughness properties of SBS modified sludge asphalt are much improved, and its storage-stability is better than conventional SBS modified industrial binders. The results revealed that SBA is a stable binder for containing calcium sulphate interacted with SBS, and it can be confidently used as paving materials, hence a promising disposal method for acid sludge of used oil.