Adhesion Of Asphalt Research Articles

Atomic force microscope study of the aging/rejuvenating effect on asphalt morphology and adhesion performance

Asphalt aging is one of the most severe threats to the asphalt pavement durability and rejuvenation with cooking oil can help to resolve this issue. Currently, the influence of aging/rejuvenation on the bonding performance of asphalt binder has not been fully understood. This study aims to unveil the influence of aging/rejuvenation on the adhesion performance under both micro and macro scale tests. Three type asphalt binders were examined in this study, including the original, aged and rejuvenated samples. The atomic force microscope (AFM) was first applied to examine the surface morphology and adhesion performance of the three type asphalt samples. It is found that the aging effect can increase the adhesion between asphalt binder and silica particles and the adhesion force can be further enhanced through rejuvenation. Then the three-point bending was further conducted to examine adhesion performance at the macroscale, and the obtained results are in accordance with those obtained at the microscale. However, the slant shear test indicated the shear bond strength can be reduced due to the rejuvenation with vegetable oil, which can be generated due to the lubrication effect of the oil. The results in this study can help to better understand the influence of aging and rejuvenation on the bond performance between asphalt binder and mineral aggregate.

Impacts of high modulus agent and anti-rutting agent on performances of airfield asphalt pavement

Polymer modifiers have been widely used in asphalt binders to improve the high temperature performances and rutting resistances in airfield pavement. The objective of this study was to investigate the high and low temperature performances of three polymers and styrene–butadienestyrene (SBS) modified binders before and after a short-term aging procedure, and the performances of their corresponding mixtures. A series of tests were performed to determine the effects of polymers on the binders and mixtures, such as rheological properties of the modified binders and engineering performances of mixtures at high and low temperatures. The test results show that, compared with the SBS modified binders, the polymer modifiers remarkably influenced on the virgin binders, and the high temperature performance of virgin binders with a high polymer modifiers content is similar to that of the SBS modified binders, but both SBS and polymers have negative impacts on low temperature performance. In terms of asphalt mixture, the polymer can enhance the adhesion of asphalt to improve the rutting resistance, and has appreciable effect on dynamic stability and moisture stability, but only the SBS modified asphalt mixtures with polymers have better pavement performance, the polymer modified virgin asphalt mixtures are still not applicable to the airfield pavement.

Sustainable utilization of lime kiln dust as active filler in hot mix asphalt with moisture damage resistance

The Australian flexible road pavement network is experiencing a considerable degree of reveling and stripping damage in association with moisture. The next generation of hot mix asphalt (HMA) mixtures in Australia needs to have excellent engineering properties as well as higher resistance to moisture damage. Hydrated lime (HL) with a relatively high content of active lime is used in HMA mixtures to improve engineering properties, and particularly to enhance the resistance of HMA mixture to moisture. HL is currently considered a superior mineral filler to crushed rock baghouse dust but it is commercially produced and relatively expensive. Lime kiln dust (LKD) is an industrial by-product which has hydrated lime HMA filler-like properties with similar fineness and a relatively high content of active lime. The lime components in LKD assists in promoting resistance to the stripping common in siliceous acidic aggregates. This project aims to determine an optimum proportion of LKD in an LKD-asphalt binder mixture, based on the properties of viscoelasticity and aggregate adhesion. Dynamic shear rheometer testing and rolling bottle tests were used to evaluate the properties of the LKD-asphalt binder mixtures with varying LKD content. The test results indicated that a 50% LKD content in the LKD-HMA binder mixture provided superior viscoelasticity properties., an acceptable adhesion of asphalt to aggregates was also observed. Last but not the least, a ‘cradle to gate’ life cycle assessment was carried out to capture the benefits of the use of LKD by-product. This showed that GHG emissions and embodied energy demand could potentially be reduced by 18.5% and 2.4%, respectively if a 50% LKD asphalt binder by mass mixture was used in the LKD-HMA mix.

Evaluation Method of Resistance to Water Damage for Foamed Warm-Mixed Asphalt Mixture Based on Surface Free Energy Theory

Abstract Weak adhesion between asphalt and aggregates is the main cause of moisture-induced damage for asphalt pavement, especially for foamed warm-mixed asphalt pavement, because of low mix temperatures and residual moisture left behind by the microscopic foaming process. In order to improve the road performance of foamed warm-mixed asphalt mixture, the law of moisture evaporation of foamed asphalt was discussed through laboratory foaming test in this article. The surface free energy of foamed asphalt in different foaming stages and two kinds of aggregates were obtained by measuring contact angle via the sessile drop method. The work of cohesion and adhesion between asphalt and aggregates and the work of stripping were calculated through using their surface free energy parameters. On this basis, the energy ratio (ER) is proposed as an indicator to evaluate the anti-water damage property of foamed warm-mixed asphalt mixture, and the ER is obtained by calculating the ratio of work of adhesion and the work of stripping. This method can be used as the reference for the evaluation of asphalt adhesion. The results may show that the resistance to moisture-induced damage of asphalt is improved after foaming process.

Anti-asphalt properties of PPS/PTFE composite coatings at high temperature

ABSTRACTDuring the process of preparing coal tar pitch and petroleum asphalt, it is technically difficult to remove adhered asphalt through heating, chemical solvents, mechanical methods, etc. In this paper, polyphenylene sulphide/polytetrafluoroethylene (PPS/PTFE) composite coatings were fabricated on stainless steel specimens to study the adhesion of asphalt. Specimens were immersed in hot asphalt and taken out to calculate the coverage area, which was set as the standard for measuring the anti-asphalt properties. Moreover, the surfaces of the PPS/PTFE composite coatings were investigated by means of scanning electron microscopy (SEM), Fourier transform-infrared spectroscopy (FT-IR) and energy-dispersive system (EDS). As the FT-IR and EDS results reveal, the PPS generated a severely oxidative reaction, and the PTFE macromolecule chain shifted gradually from the coating's interior to the surface. The PPS/40%PTFE coating exhibited the most adequate performance, which showed the best anti-asphalt behaviour, high temperature performance and strong adherence behaviours.

Atomistic modelling of moisture sensitivity: a damage mechanisms study of asphalt concrete interfaces

Moisture-induced damage mechanisms are characterised by adhesive bond strength reduction at the aggregate–asphalt interfaces. This research examined the physicochemical phenomena that occur at the asphalt–aggregate interfaces, as well as the nanoscale effect of water molecules on the asphalt–aggregate bond using atomistic simulations. The moisture sensitivity behaviour of model asphalt, water molecules, and mineral aggregates of various components was evaluated. Steered molecular dynamics was used to study the interfacial atomic separation under dry and wet conditions. The effect of water on the bond strength between asphalt and aggregate was described through surface free energy studies. It was found that the adhesion and stripping behaviours between asphalt and aggregate were more strongly influenced by the aggregate chemistry and properties than those of the asphalt. The adhesion of different asphalt–aggregate pairs and their susceptibility to water were also validated by available experimental results and pavement engineering observations. This work provides an insight into the orientation and interaction of asphalt molecules in the wet interfaces.

Evaluation of Adhesion Properties of Modified Asphalt Binders with Use of Binder Bond Strength Test

Moisture damage is a prominent problem of asphalt pavements. The bond strength between asphalt and aggregates is a crucial factor that influences the capability of asphalt to resist moisture-induced damage. In this study, a binder bond strength (BBS) test was conducted to evaluate the effects of various modifiers and additives of different amounts on bond strength between asphalt and aggregates. Furthermore, the influence of styrene–butadiene–styrene (SBS) on adhesion behavior of asphalt binder was investigated through a gel permeation chromatography (GPC) test. Finally, the results of the BBS test were compared with the findings obtained from a Hamburg wheel-tracking device (HWTD) test, which reflected the moisture sensitivity of mixtures under wet conditions. Results indicated that gilsonite, high-density polyethylene, and polyphosphoric acid improved the bond strength of the base asphalt; SBS had no positive effects on asphalt adhesion properties; and SBS at a low amount reduced the bond strength. Ethylene bis-stearamide wax, crumb rubber, terminal blend (TB) rubber powder, and compound modifier TB rubber powder plus SBS decreased the bond strength. The GPC test results showed that SBS possibly did not actively contribute to the formation of bond strength between asphalt and aggregates. Test data for BBS and HWTD tests under wet conditions confirmed that there was no discernible correlation between these two tests when adhesion properties of modified asphalts were evaluated. However, the results of the BBS test were in accordance with those of the HWTD test when the adhesion of asphalt with different amounts of the same modifier and the mixture resistance to water damage were evaluated.

Evaluating the effect of asphalt binder modification using nanomaterials on the moisture damage of hot mix asphalt

One of the most common damages in asphalt mixtures is due to the destructive effects of moisture on the cohesion of asphalt binder and adhesion of asphalt binder–aggregate which is called moisture damage. There are several different approaches for improving adhesion and reducing moisture sensitivity in asphalt mixtures. One convenient approach is modifying the asphalt binder with a suitable agent. In this research, the effects of two types of nanomaterials in two different percentages (nano AL2O3 and Fe2O3), two types of aggregates (granite and quartzite), and one base asphalt binder were evaluated. To assess the effect of nanomaterials, the tensile strength ratio (in 1, 3, and 5 freeze–thaw cycles) and surface free energy (SFE) tests have been used. Mechanical test results used in this study show that using nanomaterials significantly improves the moisture strength of samples made with the modified asphalt binder in comparison with the control samples. Results of SFE theory show that the nanomaterials increase the cohesion free energy of the asphalt binder that decreases the probability of the occurrence of cohesion failure in the mastic. Also, nanomaterials decrease the acid component and increase the base component of SFE of the asphalt binder which increase its adhesion with the aggregates used in this study with acid properties. Measurement results of debonding energy of the asphalt binder–aggregate in wet conditions show that asphalt binder modification with nanomaterials decreases the absolute value of the debonding energy and, therefore, the moisture damage susceptibility decreased.

Adhesive properties of asphalts and aggregates in tropical climates

In Central and South America, pavement deterioration due to moisture is high. The deterioration is directly related to the compatibility between the asphalt and aggregates, as well as the cohesiveness of the asphalt matrix. The affinity between these materials affects how well the bond will behave in the presence of water, and therefore the susceptibility of the asphalt mixture to moisture in the long term. It is well accepted that traditional tests for assessing moisture damage are not necessarily representative of high moisture conditions, such as those present in Colombia and Costa Rica. Therefore, it is imperative that methods to quantify the actual moisture susceptibility of hot-mix asphalt be adopted and implemented in local specifications. In order to characterise the true adhesion properties of regional materials, both physicochemical and mechanical analysis has been implemented to determine the moisture susceptibility of different binder–aggregate combinations typically used in Costa Rica and Colombia. The effect of antistrip additives on the water resistance of such combinations was also evaluated. The asphalt bond strength test was applied to mechanically determine the adhesive and cohesive strength of the binder–aggregate pairs. In addition, the measurement of physicochemical properties such as surface free energies of aggregates and binders allowed the determination of work of adhesion, cohesion and debonding of asphalt from the aggregate surface in the presence of water. A correlation between the physicochemical and the mechanical properties was found for most of the cases.

Utilization of gneiss coarse aggregate and steel slag fine aggregate in asphalt mixture

Natural resource shortage and environmental pollution issue have promoted the recycling of inferior natural resources and solid wastes in asphalt pavement. While steel slag fine aggregate and inferior gneiss aggregate are rarely used in asphalt mixture in China due to some poor performances. The primary objective of this research was to explore the feasibility of simultaneously using gneiss coarse aggregate and steel slag fine aggregate in asphalt mixture. A new method to improve the quality of steel slag fine aggregate was proposed first. Raw material characteristics directly related to asphalt adhesion and absorption were fully detected then. Performances of asphalt mixture including Marshall stability and quotient, crack resistance, moisture susceptibility, volume stability and deformation resistance were evaluated finally. Results showed that modified WSFA (Weathered Steel Slag Fine Aggregate) presented lower asphalt absorption than original WSFA. Asphalt mixture consist of gneiss coarse aggregate and modified WSFA obtained better crack resistance, moisture resistance, volume stability and deformation resistance.

Failure Probability of Resurfaced Preventive Maintenance Treatments

This study evaluated the effectiveness of various pavement preventive maintenance treatments through investigation of the failure probability of different performance indicators, including roughness, alligator cracking, longitudinal cracking, transverse cracking, rutting, and friction. For the study, 354 resurfacing pavement preventive maintenance projects were collected from the Long-Term Pavement Performance program database, including ones that used thin asphalt overlay, chip seal, slurry seal, and fog seal. Survival models were employed to conduct the analyses because of their capability to capture unobserved failure events and to systematically incorporate influencing factors (e.g., traffic, climate, pavement structural capacity, and pretreatment pavement performance). The statistical analysis showed that poor pretreatment performance was a significant factor in treatment failure and that preventive treatments would not be effective on pavement in poor condition. Stronger structural capacity of pavement greatly reduced fatigue cracking on the treatment surface: the bending of asphalt layer was alleviated through stronger base and subgrade support. Climate factors had a significant influence on the failure of transverse cracking and rutting and on friction loss. A warmer climate tended to cause permanent deformation and friction loss, probably as the result of asphalt softening. In general, chip seal was the most effective overall, followed by thin asphalt overlay, slurry seal, and fog seal. However, chip seal was vulnerable to friction loss: the aggregates could be pulled out as a result of the loss of asphalt adhesion.

The Summary of Warm-Mixed Flame Retardant Asphalt Acting Mechanism and Adhesion

Warm mix technology can effectively reduce construction temperature, save energy and reduce environmental pollution, and did not reduce road performance. Retardant technology can effectively inhibit the combustion of asphalt pavement to reduce the generation of smoke. Both at home and abroad for studies in general tend to macroscopic properties and other aspects of road performance, it is necessary to explore the mechanism of its microscopic. This article reviews the large number of domestic and foreign literature, this focus on thermal gravimetric analysis, differential analysis of several common scanning calorimetry and asphalt adhesion evaluation, get a lot of reliable test conclusions for relevant research scholars reference.

Using energy parameters based on the surface free energy concept to evaluate the moisture susceptibility of hot mix asphalt

Although the conventional laboratory test procedure is helpful in comparative analysis of moisture susceptibility of hot mix asphalt (HMA), it does not focus on measuring the fundamental material properties related to the mechanisms of moisture damage. In this study, comparing results of tensile strength ratio test and surface free energy method resulted in the determination of important energy parameters that can be employed as a quantitative indicator to assess moisture susceptibility of HMA. Three of the four parameters used in this research have a convenient correlation with the laboratory results. The ratio of the difference between the surface adhesion of asphalt–aggregate and the water–aggregate to the surface adhesion of the asphalt–aggregate (EP1) had the best correlation with the tensile strength ratio of 32 types of asphalt mixtures. This parameter can be used as a tool for moisture sensitivity detection with more caution. Also, the ratio of the surface energy of adhesion of the asphalt–aggregate to the difference between the surface energy of adhesion in dry and wet conditions (EP2) had good correlation with laboratory results.

The Research of Shear Property of SBS Modified Asphalt and Aggregated Rock

In view of the limitation that happens when the adhesion between SBS modified asphalt and aggregated rock is evaluated by water-boiling method, on the basis of adhesion mechanism analysis of asphalt and aggregated rock, we design the evaluation method of the adhesion between asphalt and aggregated rock based on shear test, advance the quantitative index to evaluate the adhesion——shear strength, and validate the feasibility of shear strength index, analyze how the type and dosage of SBS modifier and the temperature of test influence the adhesive effect of SBS modified asphalt and aggregated rock. Result shows that The incorporation of SBS significantly improve the adhesion of asphalt and stone , especially the effect of star-modified asphalt and with the increase of dosage of SBS ,the adhension of asphalt and stone significantly increased, the shear strength of SBS modified asphalt and stone is increased about 100% than matrix asphalt when the dosage is 4%. It also describes that the shear strength index can quantitatively evaluate the effect of asphalt binder and aggregates to provide a reference for performance evaluation and quality control of modified asphalt .

Investigation of Usability of Brucite Fiber in Asphalt Mixture

The objective of this study is to investigate the usability of brucite fiber in asphalt mixture. In order to compare the characteristics of brucite fiber with other fibers usually used in asphalt mixtures, the water absorption test, oven heating test, Mesh-basket draindown test, and scanning electron microscopy are conducted on brucite fiber, lignin fiber, basalt fiber, and polyester fiber. Also, the Marshall test, wheel tracking test, low temperature bending test, water sensitivity test, and fatigue test are used to evaluate the performance of different fiber-reinforced asphalt mixtures. These experimental results show that brucite fiber has a good state of preservation in the moist storage environment, and its thermo-stability is better than lignin fiber. Its absorption and adhesion of asphalt is better than basalt fiber and polyester fiber. The best performance of asphalt mixtures are obtained for 0.40% brucite fiber content. Asphalt mixture prepared with brucite fiber also has excellent high temperature stability, water sensitivity, and fatigue property, especially low temperature properties. Addition of brucite fiber is feasible to improve major performance properties of asphalt mixture.

Neural network modelling of asphalt adhesion determined by AFM

This study constructs a neural network (NN) model to quantify adhesion from atomic force microscopy (AFM) data. AFM data contain five-point force-distance values. A total of 760 observations are used to build NN model. To train the network, AFM tip-sample distance data, percentage of lime, type and percentage of polymer and asphalt chemical functional groups are given as inputs and AFM force as an output. To select the NN architecture, one and two hidden layers with varying neurons are tried with 10 input nodes in the input layer and 5 output nodes in the output layer. Two hidden layers with 9 and 17 nodes in the first and second layer, respectively, show the best performance. A 10-9-17-5 NN is selected as the final structure of the NN model. Test results for the trained model show good prediction ability. The model is further applied to evaluate the effect of five different percentages of lime on the adhesion of asphalt. Results show that increase in the percentage of lime is very effective at reducing moisture damage in a styrene butadiene polymer modified asphalt sample. However, increase in lime percentage above 1.5% does not help reduce moisture damage in the styrene butadiene styrene polymer modified sample.

A Study on Improving the Adhesiveness between Granite and Asphalt by Nano-Scaled Calcium Carbonate

Granite, due to the poor adhesiveness with asphalt, cannot be widely used as aggregate in asphalt pavement. In this study, nanoscaled calcium carbonate (CaCO3), was selected as modifier to modify asphalt. The adhesion of aggregate and asphalt was evaluated by Boiling test method and the Marshall Test and Immersion Marshall Test were conducted on asphalt concrete (AC-16) according to the Standard Test Methods of Bitumen and Bituminous Mixture for Highway Engineering (JTG E20-2011). The results showed that When the Doping content of CaCO3 (%) is 7%, the adhesion levels reached up to 5 grade and achieved the project requirements. The Immersion Marshall Stability (MS1) of AC-16 CaCO3 modified asphalt concrete can improve 27.6% than that the Matrix asphalt concrete.

Phased Evaluation Theory and Study on Adhesion between Asphalt and Stone Based on Surface Energy Theory

As for the existing surface energy adhesion theories which are used to evaluate asphalt and stone's adhesive performance quantitatively, they are either dealing with the interface between solid asphalt and solid stone which can not adhere according to the formulas and definitions in process of adhesion or else roughly characterizing the solid asphalt and stone's adhesion properties with the adhesion index of heated asphalt and solid stone. So according to the forming process of asphalt mixture , this paper puts forward the method and principle to evaluate asphalt and stone's adhesion based on the surface energy theory. It evaluates the adhesion properties of asphalt and stone under hydrous and anhydrous conditions respectively. In the anhydrous condition, we choose contact angle and the Gibbs free energy of failure stage as the indexes of evaluating asphalt - stone interface's adhesion properties, while the materials under the hydrous condition, we select cohesional work, contact angle, Gibbs free energy as the indexes of evaluating asphalt-stone system's resistance of moisture.

Using surface free energy method to study the cohesion and adhesion of asphalt mastic

In order to improve the road performance of asphalt mixture, the cohesion and adhesion of asphalt mastic which is the most important component of asphalt mixture were studied. The surface free energy of asphalt was tested using sessile drop method, and the surface free energy of fillers was measured using column wicking method. The work of cohesion and adhesion between asphalt and fillers were calculated through using their surface free energy parameters. The results show that the neat asphalt has higher surface free energy than the modified asphalt. The van der Waals force of surface free energy plays a more important role. The polarity power of modified asphalt is higher than the neat asphalt. The Lewis acid–alkali forces of different fillers have a big difference, while the van der Waals forces are nearly the same. Limestone filler has the biggest surface free energy and the components, and granite filler has the smallest intermolecular forces, and andesite filler has the smallest Lewis acid–alkali force. The specific surface area is an important parameter effecting the interfacial interaction between asphalt and fillers. The work of adhesion at a constant volume ratio has a better regularity than at a constant specific surface area regardless of whether the condition is dry or damp, whether the asphalt is modified or not, and the order is granite filler>andesite filler>limestone filler. A good correlation exists between complex modulus G∗ and work of adhesion.

Synthesis and modification of low-molecular-weight polybutadiene and polystyrene for use as adhesive additive to asphalt

Low-molecular-weight butadiene and styrene polymers with narrow molecular-weight distribution were prepared by the mechanism of living polymerization with front initiation. Introduction of deactivating nitrogen-containing agents (α-pyrrolidone, N-methylpyrrolildone, caprolactam, urea) into living polymer chains allows preparation of effective adhesion additives to asphalt, improving the adhesion of asphalt to the mineral filler.