Cutback Asphalt Research Articles

Evaluation of Using Vacuum Oven for Residue Recovery of Asphalt Emulsion and Cutback Asphalt for Routine Screening

Evaluation of Using Vacuum Oven for Residue Recovery of Asphalt Emulsion and Cutback Asphalt for Routine Screening

Evaluation of Bonding Adhesion Strength and Failure Modes of Different Types of Cutback Asphalts

Evaluation of Bonding Adhesion Strength and Failure Modes of Different Types of Cutback Asphalts

Assessing bio-oil cutback asphalt for prime coat on semi-rigid base asphalt pavement: Lab experiment & indoor test section application

To analyze the potential utilization of bio-oil cutback asphalt (BCA) as an innovative permeable material, this study comprehensively evaluated the road performance of BCA. Infrared spectroscopy and fluorescence microscopy were employed to characterize the components' interaction mechanisms and storage stability within the BCA. The research also involved assessments of interlayer strength, unconfined compressive strength, and dynamic water scouring trials of the base layer. Subsequently, a comprehensive assessment of the road performance of BCA was carried out in conjunction with its application on the indoor test section. The microscopic test results revealed that bio-oil and the penetrant primarily enhanced the asphalt's flow and penetration properties through physical blending. Even after 28 days of storage, no phase separation occurred among the constituents in the BCA. Compared to conventional prime coat materials, the specimens treated with BCA demonstrated notably higher interlayer pull-off and shear strengths at the optimal sprinkling volume. Furthermore, applying BCA to the cement-treated base improved its early strength and erosion resistance. As a result, BCA plays a crucial role in enhancing the structural integrity of asphalt pavements with semi-rigid base layers.

Anthropogenic Secondary Organic Aerosol and Ozone Production from Asphalt-Related Emissions.

Liquid asphalt is a petroleum-derived substance commonly used in construction activities. Recent work has identified lower volatility, reactive organic carbon from asphalt as an overlooked source of secondary organic aerosol (SOA) precursor emissions. Here, we leverage potential emission estimates and usage data to construct a bottom-up inventory of asphalt-related emissions in the United States. In 2018, we estimate that hot-mix, warm-mix, emulsified, cutback, and roofing asphalt generated ~380 Gg (317 Gg - 447 Gg) of organic compound emissions. The impacts of these emissions on anthropogenic SOA and ozone throughout the contiguous United States are estimated using photochemical modeling. In several major cities, asphalt-related emissions can increase modeled summertime SOA, on average, by 0.1 - 0.2 μg m-3 (2-4% of SOA) and may reach up to 0.5 μg m-3 at noontime on select days. The influence of asphalt-related emissions on modeled ozone are generally small (~0.1 ppb). We estimate that asphalt paving-related emissions are half of what they were nearly 50 years ago, largely due to the concerted efforts to reduce emissions from cutback asphalts. If on-road mobile emissions continue their multidecadal decline, contributions of urban SOA from evaporative and non-road mobile sources will continue to grow in relative importance.

Enhancing Shear Strength of Bonding Materials Used for Asphalt Concrete and Composite Pavement Layers

A tack coat is a thin cut-back cement or asphalt emulsion coating applied on an existing non-absorbent pavement. A good bonding between the asphalt and concrete is necessary to provide sufficient structural strength. Poor adhesion will result in shear failure. The shear test is one of the basic tests to determine bond strength. This study aims to quantify the best shear resistance obtained using three types of cut-back asphalts (RC70, RC800 modified with polymer 4.5% and MC70), PG (76-10) modified asphalt cement with polymer 4.5%, Sikadur®-31 CF usage at elevated temperatures between +25°C and +45°C and Nitomortar TC2000 epoxy from Fosrok company. All are applied on concrete surfaces with an application rate of 0.5kg/m2 except for Nitomortar, which depends on layer thickness ranges between (1-2.5) mm instead of the application rate. A special attachment and loading mechanism were designed to facilitate the measurement of the asphalt-to-concrete contact shear strength in Al-Ahmad Lab-Baghdad. Vertical shear force is applied to a multiple-layer sample with a 0.25 kN/sec rate until the failure occurs at the interface. The final result of this test is stated in terms of the maximal force or power needed to break the bond. The average shear strength of tack coat materials is (0.049, 0.0455, 0.0085, 0.677, 1.088, 1.361) MPa Respectively. It concluded that Fosrok epoxy has the maximum shear strength. Also, adding polymer to asphalt increased the viscosity. All materials used enhanced the shear strength of bonding materials used for asphalt concrete and composite pavement layers

Evaluation of Bonding Interior Layer Failure Strength Modes in the Composite Pavement

A tack coat is a minimal coating of asphalt cement, cut-back asphalt, or asphalt emulsion to an existing pavement surface between layers to guarantee proper bonding between the two layers and longitudinal and transverse Joints. Numerous researchers have assessed interlayer adhesion employing failure-mode behavior tests, such as pull-off, direct shear, and torsion testing. This study aims to quantify the best tensile resistance obtained using PG (76-10) modified asphalt cement with polymer 4.5%, Sikadur®-31 CF (S.E) usage at elevated temperatures between +25 °C and +45 °C, an epoxy-resin-based adhesive, and repair mortar with specific fillers. And Nitomortar TC2000 epoxy (F.E) resin-based sealing compound from Fosrok Company. All are applied on concrete surfaces at a rate of 0.5 kg/m2 except for Nitomortar, which depends on layer thickness ranges between (1-2.5) mm instead of the application rate. The Proceq DYNA Z16 pull–off tester is used to measure the tensile strength at a rate of 2lb/s. It is found that the average tensile strength of the tack coat materials is (0.607, 1.481, 2.622) MPa, respectively. It concluded that (F.E) epoxy has the maximum tensile strength. Also, adding polymer to asphalt increased adhesiveness. Failure strength modes of interior bonding varied between cohesive failure adhesive, adhesive failure, and cohesive failure in the concrete substrate.

Laboratory investigation on performance of waste-oil cutback asphalt as prime coat on cement stabilized macadam base

The commonly used prime coat materials have shortages such as insufficient interlayer bonding performance, high cost, and serious environmental pollution. To solve the above problems, this study attempts to take waste-oil as the diluent and blend it with asphalt to prepare a new prime coat material: waste-oil cutback asphalt. And the feasibility of this prime coat material is studied on semi-rigid base. Through penetration test, direct shear test, and pull-out test, the optimum blending proportions and construction conditions of the waste-oil cutback asphalt are determined, and the feasibility of the waste-oil cutback asphalt was evaluated by comparing it with kerosene cutback asphalt and PC-2 emulsified asphalt. The results illustrate that the mass ratio of waste-oil to asphalt is 1:1, and the content of penetrant is 10 % of the asphalt mass (47.6 % waste-oil, 47.6 % asphalt, 4.8 % penetrant in the percentage of 100 %) can be used as the optimum blending proportion of waste-oil cutback asphalt. The average penetration depth of waste-oil cutback asphalt is 5.4 mm, which meet the standard requirements. The direct shear strength is 0.292 MPa, which is 23.7 % and 86.0 % higher than that of PC-2 emulsified asphalt and kerosene cutback asphalt. And the pull-out strength is 0.235Mpa, which is 11.4 % and 92.6 % higher than that of theirs. The optimum construction condition is 1.1 L/m2, and the best construction time is 1 day after the construction of the base course. It indicated the interlayer bonding performance of waste-oil cutback asphalt is significantly improved than traditional prime coat materials. Thus, the waste-oil cutback asphalt can be used as a new type of environmentally friendly and high-performance prime coat material on cement stabilized macadam base.

Enhancing Reol ogical Properties of liquid Asphalt

The purpose of this study is to improve the specifications of cut back asphalt (S125) in orderto use in the treatment of holes, potholes and cracks of roads. Different methods were carried outto enhance physical and mechanical properties and to get better construction behavior. Thesetreatments are:-First: The vacuum distillation of S125 cut back asphalt was employed to remove oil, vacuumgas oil and vacuum residue as a rapid curing. FTIR spectra of the four fractions of S125 wererecorded. It was observed a low penetration and high softening point for the vacuum residue.Second: extraction method using ethanol as a solvent was employed to extract light componentthat could be in the S125 cut back asphalt. The results indicated that the softening point washighly increased and the penetration as well as ductility was decreased to minimized level.Third: Some Polymers were used as cross linking agent such as melamine and phenolformaldehyde resins.Fourth: The unsaturated monomers were polymerized free radically to increase thesolidification of S125.Fifth: The hydrated white cement was used as additive to the S125 cutback asphalt at differentratios to improve the properties. This method was observed as a suitable and economic method,and easy employed compared to others and the best rheological behaviors were given in thismethod. Also the vacuum distillation method gave high improvements in rheological propertiesfor asphalt residue.

Assessing the Moisture and Aging Susceptibility of Cold Mix Asphalt Concrete

Laboratory experience in Iraq with cold asphalt concrete mixtures is very limited. The design and use of cold mixed asphalt concrete had no technical requirements. In this study, two asphalt concrete mixtures used for the base course were prepared in the laboratory using conventional cold-mixing techniques to test cold asphalt mixture (CAM) against aging and moisture susceptibility. Cold asphalt mixtures specimens have been prepared in the lab with cutback and emulsion binders, different fillers, and curing times. Based on the Marshal test result, the cutback proportion was selected with the filler, also based on the Marshal test emulsion. The first mixture was medium setting cationic emulsion (MSCE) as a binder, hydrated lime, and ordinary portland cement as a filler (7.95% MSCE + 2%HL + 3% OPC). The second mixture used was medium curing cutback (MC-250) as a binder and ordinary portland cement as a filler (5.18% MC 250 + 5% OPC). The indirect tensile strength (ITS) of the samples was measured at 25 ° C. It was found that the cold mix with the MSCE binder had a high ITS value relative to the cold mix with the cutback asphalt binder (MC-250). The dry mixture of MSCE ITS was approximately 3.77 times the dry mixture of MC-250. The MSCE wet mix was about 4.2 times the wet MC-250 mix. Tensile strength ratio result (TSR %) for the MSCE binder mix and the cutback MC-250 binder mix showed that the MSCE mix has a reasonable moisture resistance (77% ) compared to the MC-250 mix (69.2 %). The aging test and aging ratio result showed that asphalt binder oxidation has a significant effect on age-related pavement degradation as it changes the time-temperature relationship depending on the viscoelastic properties of the asphalt binder. The result clearly showed that the MSCE binder mix had a high resistance to aging (440 Kpa) compared to the cutback (MC-250) binder mix (110 Kpa). In contrast, the MSCE aging ratio (90 %) was higher than the MC-250 ratio (85 %).

Effect of the Solvents Content on the Mechanical Response and Compactability of Asphalt Mixtures Fabricated Using Castilla’s Paving-Heavy Crude Oils

The paving-heavy crude oils (PHCO) are natural cut-back asphalts composed by a high content of asphalt cement and a portion of solvents. These materials have been used in Colombia since the 90’s to improve low volume traffic roads. The existence of solvents in the PHCO allows mixing it with the aggregates in cold conditions. Then, before compaction, these asphalt mixtures require a curing process (i.e., process of partial loss of solvents from the PHCO) to ensure its proper performance. However, at present there is no consensus on the loss of solvents to specify for the curing process of mixtures fabricated with PHCO. Given this situation, this study assesses the effect of the partial content of solvents on both the mechanical response and compactability of asphalt mixtures produced using PHCO from the Castilla’s oil field (CA); a material extensively used in the East region of Colombia. The study included conducting and analyzing conventional characterization tests of the mixture constituent materials, surface free energy testing on both mastics and the aggregate, mix design, and characterization of both mechanical response and compactability of the mixtures fabricated using the CA and a control asphalt. Corresponding results led to identify and quantify a progressive improvement in both the adhesion quality of the mastic-aggregate interfaces and the mechanical response of the asphalt mixture as a function of the reduction of the solvents. These results suggest the convenience of compacting the asphalt mixtures fabricated using the CA after allowing a loss of 50% of the solvents obtained from the CA via atmospheric distillation at 360°C.

Material Properties of Porous Asphalt Pavement Cold Patch Mixtures with Different Solvents

This laboratory study investigated the performance of open-gradation cold patch asphalt mixtures using two new solvents, mineral spirit and isoamyl acetate, for patching potholes in porous pavements. Mineral spirit and isoamyl acetate were used as the solvents to produce the cutback asphalt. The test results showed that the mineral spirit and isoamyl acetate cold mixes had greater initial and cured strengths, cohesiveness values, anticracking performances, and rutting resistance than did diesel cold mix; in addition, the mineral spirit and isoamyl acetate cold mixes had lower moisture susceptibility than did the diesel cold mix. The improved coating, mixing, and curing of the new cutback cold mixes were due primarily to the better solubility of the two new solvents with asphalt and their high evaporation rates. For a 100-kg mixture, using the mineral spirit and isoamyl acetate cutback mixes costs $2 and $3 more, respectively, than using the diesel cutback mix. Considering the cost and toxicity level, the mineral spirit cutback cold mix had better overall performance and ecoefficiency.

Development of a Turpentine Cutback Asphalt Mixture for Porous Pavement Pothole Repair

AbstractPothole repair for porous pavements requires the patching mixture to have sufficient connected air voids, high strength, low moisture susceptibility, and high abrasion resistance. In this s...

Microcapsule and polymer reinforcement techniques developed asphalt for use of pothole repairs in winter and rainy seasons

This paper proposes a new Polymer Modified Asphalt (PMA) for cold mixtures used to patch potholes in the adverse weather conditions of low temperature and rain. The new PMA is based on the microcapsules and polymer reinforcement techniques. Test results of the PMA binder found that the PMA improved the performance of the asphalt in low temperature and improved the adhesion of the cold mixtures by importing corresponding foundational groups. For example, the conjugated olefinic bond was used in the microcapsule formation and polybutadiene was used to improve the performance in low temperature as compared with the matrix asphalt and terpene resin cutback asphalt (TRCA). The modifier and adhesive stored in the microcapsules were distributed evenly in the asphalt. Test results of the cold mixtures verified that the PMA mixtures had a better performance than the TRCA mixtures, involving cohesion, stability and freeze-thaw resistance. Field surveys taken over 12 months indicated that the pothole patches filled with the PMA patching materials met the requirement for ride-ability and traffic safety standards. Therefore, it is concluded that the PMA is an adequate asphalt binder for pothole repairs in cold temperature and wet conditions.

Moisture Damage of Warm Mix Asphalt Concrete

Implementation of Warm Mix Asphalt concrete (WMA) is getting global acceptance due to the restrictions for protecting the environment and the requirements to reduce fuel consumption. In this investigation, two WMA mixtures have been prepared in the laboratory using medium curing cutback (MC-30) and Cationic emulsion asphalt. Hot Mix Asphalt (HMA) was also prepared for comparison. The cylinder specimens (63.5mm) in height and (101.6mm) in diameter were constructed from the mixtures and subjected to indirect tensile strength test to determine the Tensile Strength Ratio (TSR). The cylinder specimens of (101.6mm) in height and (101.6mm) in diameter were also constructed from those mixtures and subjected to static compressive strength test to determine the Index of Retained Strength (IRS). It was concluded that the WMA are more prone to moisture damage than HMA, the TSR are (92 and 86) % for (emulsion and cutback) WMA respectively, both are lower than of HMA by (2.13 and 8.51) % respectively. As the asphalt content increases, the TSR also increases and reached to peak value of Optimum Asphalt Content (OAC) then decreases. The WMA has less IRS than HMA, the IRS are 70% and 78% for the WMA-emulsified asphalt and HMA respectively.

New polyurethane modified coating for maintenance of asphalt pavement potholes in winter-rainy condition

Potholes are common distresses on poor quality or heavily trafficked asphalt pavements. Timely and durable maintenance is required to reduce the impacts on traffic, especially in winter and rainy conditions. Conventional coating materials for repair either require complex preparation or are of poor durability. This paper introduces a new polyurethane modified coating material to be used in pothole repairs, and compares it with the other two coating materials which are widely used in pothole maintenance, i.e., emulsified asphalt and cutback asphalt. Laboratory tests concerning workability, bonding performance and durability, and field surveys of three pothole patches installed in different environments were conducted. The results showed that the curing time and workability performance of the polyurethane modified coating were stronger than that of the control materials in low temperatures. Shear strength and pullout strength were greater at different test temperatures and moisture levels. The use of the polyurethane modified coating enhanced the ability of pothole patches to resist freezing-thawing cycles, dishing and shoving, when compared with the emulsified asphalt and cutback asphalt. The polyurethane modified coating had good pavement performance in field as well. Therefore, it is concluded that the polyurethane modified coating is a suitable choice for timely asphalt pavement potholes maintenance in cold and wet conditions.

Calidad de adhesión y propiedades reológicas de asfaltos residuales, no modificados y nano-modificados, obtenidos de crudos pesados de pavimentación

Los crudos pesados de pavimentación (CPP) constituyen asfaltos líquidos naturales que pueden ser empleados en soluciones de pavimentación no convencionales para vías de tránsito bajo y medio por su menor costo en comparación con el de cementos asfálticos convencionales (i.e., producidos mediante refinación de crudos de petróleo). A pesar de su potencial, la caracterización y el uso de CPP en pavimentación vial son aún limitados. Este estudio evalúa la calidad de la adhesión y las propiedades reológicas de asfaltos residuales (AR), no modificados y nano-modificados, obtenidos de CPP. Los resultados sugieren que los AR ofrecen menor rigidez y desarrollan interfases asfalto-agregado con menor calidad de adhesión que las generadas por el asfalto convencional de control. En general, el nano-modificador redujo la rigidez de los AR, y aunque mejoró la adhesión en seco, no redujo la susceptibilidad al daño por humedad en las interfases asfalto-agregado. Se sugiere investigación futura que valide los resultados a través de la evaluación de mezclas asfálticas.

Deformation and Resilient Behavior of Hot and Warm Mix Asphalt Concrete

Development of hazardous gases emissions through the production and construction of Hot Mix Asphalt (HMA) have encouraged the transition to Warm Mix Asphalt (WMA) which is considered as one of the best choices of sustainable materials in asphalt pavement. The temperature reduction in the mixing, handling, and compaction of the mix gets in saving energy, cutting emissions and significant cuts in construction costs. In this investigation, two WMA mixtures have been prepared in the laboratory using medium curing cutback (MC-30) and cationic emulsion asphalt. HMA mixture was also prepared for comparison. Marshall size Specimens of (101.6 mm) in diameter and (63.5 mm) in height were constructed from these mixtures and subjected to repeated Indirect Tensile Strength test (ITS) to determine the effect of asphalt type and content on deformation and resilient behavior of asphalt mixture. Another group of cylindrical specimens of (101.6 mm) diameter and (101.6 mm) in height have been constructed from these mixtures and subjected to repeated compressive stresses test to determine the rutting resistance of asphalt mixture. Test results were analyzed and compared. It was concluded that, the permanent deformations for cutback and emulsion treated WMA was higher than that of HMA by (50 and 35) % respectively. The Resilient Modulus (Mr) at 25 ⁰C under repeated (ITS) for cutback and emulsion treated WMA was lower than that of HMA by (39.95 and 27.94) % respectively. On the other hand, the (Mr) for cutback and emulsion treated WMA was higher than that of HMA by (43.75 and 5.47) % respectively under repeated compression load at stress level 0.138 (MPa).

Reduction of moisture susceptibility of cold asphalt mixture with Portland cement and bentonite nanoclay additives

This laboratory study investigated the effect of reducing moisture susceptibility of cutback asphalt mixture by adding Portland cement and bentonite, a nanoclay capable of absorbing water and sealing cracks through swelling. The initial strength, moisture susceptibility involving both soaking and freeze-thaw cycling, and cracking resistance at low temperature, were investigated. Test results showed that adding cement and nanoclay significantly improved the initial strength and cracking resistance, and reduced moisture susceptibility. The 20% cement content group generally had the best overall performance. The Marshall stability and indirect tensile strength were improved even after 24 h soaking or freeze-thaw cycling for the 20% cement content group, indicating the potential hydration of cement. For longer soaking time, higher cement content is associated with higher strength, which also indicated the hydration of added cement. Excessive cement caused thinner asphalt film and therefore the improvement of strength was relatively lower and the cracking resistance at low temperature was compromised. The scanning electron microscope (SEM) images showed after freeze-thaw cycling, the mixture surface changed from a smooth surface with a few wrinkles on edge of small particles to a rougher surface with gel structure. When the asphalt film was damaged during the freeze-thaw cycling, the infiltrated water reacted with encountered cement and bentonite cluster and the CSH cement hydration product was formed, sealing cracks or air voids and compensating the strength loss.

Improvement of Gypseous Soil Using Cutback Asphalt

Gypseous soils are widely distributed and especially in Iraq where arid area of hot climatic is present. These soils are considered as problematic soils; therefore this work attends to improve the geotechnical properties of such soil and reduce the dangers of collapse due to wetting process. In this research, undisturbed soil sample of 30 % gypsum content from Karbala city is used. The Single Oedometer collapse test is used in order to investigate the collapse characteristics of natural soil and after treatment with 3%, 6%, 9%, 12% and 15% of Cutback Asphalt. Moreover, two selected additive percentages (9% and 12%) are used to evaluate the suitability of using the Cutback Asphalt for improvement of the bearing capacity of gypseous soils. A steel model box is used for this purpose, the treatment depth is equal to one and twice the footing width. The tests results showed that the total settlement of 25 mm of treated soil with (MC-30) material can be achieved at vertical stress lower than that value required for natural soil. Also, thickness of treated layer with (MC-30) material below the proposed foundation has a significant effect on the value of bearing capacity of the soil. The rate of salt dissolved (C.V) is extremely decreased especially at all percentages of Cutback Asphalt. The best bearing improvement ratio is found at 9% asphalt and at a depth equal to foundation width. However, the Cutback Asphalt can be successfully used by 12% for collapse potential treatment while it is not suitable for improvement of the bearing capacity of gypseous soils.

Investigation of the interface bonding between concrete slab and asphalt overlay

Interface bonding between the cement slab and asphalt overlay is a significant point affecting mechanical behaviour and service life of the pavement. Many factors may influence the interfacial adhesive capacity, including asphalt mixture type, tack coat type and dosage, surface texture on layer below, temperature and moisture conditions. The aim of this study is to determine the most influential factors at the interlayer and evaluate their significant levels. An apparatus is designed to apply the direct shear test with normal load. Specimen is prepared by drilling cores from asphalt overlay over cement concrete pavement, which is constructed in laboratory. Six parameters with three values are examined by orthogonal test. Effects of these factors on interlayer performance are validated by boxplot. The test results conclude that surface texture on cement slab has the most significant influence on interlayer shear strength, and tack coat type, moisture and temperature come next. Rough surface texture like tining helps increase layers’ bonding. Cutback asphalt is not suitable as tack coat binder compared to emulsified asphalt. In addition, low temperature and dry condition can also improve interlayer shear performance.