Asphalt Pavement Construction Research Articles

Analysis on On-Site Asphalt Pavement Quality Inspection Technology in Highway Engineering

The acceleration of urbanization has promoted the increase in the number of urban highway projects, resulting in an increase of emphasis on the quality of urban highway projects. The quality and safety of highway construction directly affects the driving comfort, safety, and service life after it is put into operation. Among them, asphalt pavement is an important structure in highway construction, and it is also a key link that directly affects the construction quality. In order to ensure the quality of construction, it is necessary to strengthen on-site testing during the construction process to discover problems in time, and to ensure that the construction is up to standard. This paper mainly presents an analysis on the necessity and application of on-site quality inspection technology for asphalt pavement construction of highway engineering, and outlines measures to improve highway engineering construction testing technology.

Mechanical Characteristics and Durability of HMA Made of Recycled Aggregates

The application of recycled aggregates in the asphalt industry has been investigated in recent decades. However, low percentages of these materials have practically been used in asphalt mixtures because of the limitations set by the relevant specifications due to their performance uncertainties. This research investigates the feasibility of increasing the percentage of recycled aggregates to 100% in hot mix asphalt (HMA). Recycled concrete aggregate (RCA), recycled glass (RG), and reclaimed asphalt pavement (RAP) were used to develop HMAs suitable for roads with light to medium traffic. First, potential mix designs were proposed using an innovative approach considering the industry’s needs. Next, the volumetric properties, tensile strength, moisture sensitivity and resilient modulus response of the mixtures under different temperature conditions were determined and compared. In general, the proposed recycled material HMA exhibited superior mechanical and resilient modulus performances, i.e., 45 to 145% increase in stiffness, and up to 99% higher in Marshall stability. Furthermore, higher tensile strength ratios of the recycled material mixtures indicated a greater resistance to water damage, and hence greater durability. The findings of this research provide evidence-based insights into the increased proportion of recycled materials in the construction of asphalt pavements, thereby promoting sustainable pavement construction materials.

Rheological and Thermo-Oxidative Aging Properties of Asphalt Modified with a Combination of Sasobit and Linear Low-Density Polyethylene

Research of different asphalt modifiers has been necessary for the attempt to construct durable roads with higher standards. Fischer Tropsch-paraffin wax (Sasobit) has recently attracted considerable attention over polymer modification due to its capacity to lower the energy requirements for asphaltic mix construction. In this study, Sasobit was used to recover the performance as well as the workability of 3 wt% linear low-density polyethylene (LLDPE) modified asphalt. A base asphalt binder with a penetration grade of 50/70 was blended with 3 wt% LLDPE and 3 wt% Sasobit separately and then combined with different Sasobit dosages (1–3 wt%). The performance of modified asphalt binders was evaluated using conventional, rheological, and thermal tests. As a result, it was found that loading Sasobit (1–3 wt%) into LLDPE-asphalt mixture steadily decreased the penetration and ductility at 25 °C from 25 to 12 dmm and 31 to 18 cm, respectively, and softening point increased by 20% indicating improved high-temperature performance. The binder workability and mix temperature were improved since the addition of Sasobit reduced the LLDPE-asphalt viscosity from 0.292 to 0.189 Pa.s (22% less). Sasobit improved the thermo-oxidative aging resistance of the binder by showing less weight variation (less than 0.001%) after the Rolling Thin-Film Oven Test (RTFOT) and high ductility retention (65%). Thermogravimetry (TG) and kinetics analysis results indicated that Sasobit-LLDPE delayed the initial and maximum decomposition temperature by 11 °C and hence increased the thermal stability of modified binders. Thus, the proposed binders are a suitable solution for asphalt pavement construction in regions that encounter high-temperature changes.

Influence of Thermo-Oxidative Aging on the Properties of SBS-Modified Asphalt Binders

The superior performance of styrene-butadiene-styrene (SBS) modified asphalt makes it widely used in asphalt pavement construction. However, SBS-modified asphalt pavement still faces an aging problem. Aging causes the performance of asphalt materials to decline and many pavement diseases. The dosage of SBS commonly used in industry is generally between 3% and 4.5%, and the performance of SBS with a high dosage needs to be explored. Therefore, in this paper, 12 modified binders were prepared with blending amounts of 3%, 5%, and 7% and the type of modifiers as linear and star. The softening point increment (SPI), viscosity aging index (VAI), rutting factor index (RFI), complex modulus aging index (CMAI), and phase angle aging index (PAAI) were used to study the antiaging performance of SBS-modified asphalt. Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC) were used to study the microscopic and structural changes that occur during the aging process of modified asphalt. The result shows that when the amount of the same type of modifier is 3%–7%, the higher the amount of modifier, the better the performance of the modified asphalt. At the same content, a star modifier is not necessarily better than a linear modifier. For the same type of modifier, the larger the amount, the better the antiaging performance of the modified asphalt. Given an increase in aging time, the deterioration of the asphalt performance will deepen. Aging leads to the enhanced high-temperature performance of asphalt. The macroscopic performance of asphalt aging can be explained by the microscopic view. The aging process of modified asphalt is the cumulative process of oxidation products.

Evaluation of Performance of Void-Reducing Asphalt Membrane and Tack Coat on Asphalt Mixtures’ Longitudinal Joints

The longitudinal joint is one of the most crucial parts of asphalt pavement construction becuase several types of distress of the pavement can occur if the target density does not meet at the joint. A low density of asphalt pavement causes the pavement at the joint to be more exposed to water penetration, accelerating the rate of deterioration. To address this issue, asphalt agencies use various construction techniques and innovative materials to improve the joint’s performance. Void-reducing asphalt membrane (VRAM) is an innovative adhesive liquid that consists of an asphalt binder, an elastomeric polymer, and a wax modifier. In this study, field cores were collected from an Indiana state road to evaluate the VRAM and tack coat performance at the joint. Semicircular bending Illinois flexibility index (SCB-IFIT) and modified pulloff strength tests were performed to investigate the fatigue resistance and bond strength of VRAM and tack coat at the joint. Digital image analysis confirms that VRAM can migrate up to 15.88 mm (5/8 in.) from the interface. In addition, the pulloff strength test reveals that the interface bonding of the pavement containing VRAM is less than the pavement containing tack coat at low and intermediate temperatures. One of the key findings from the SCB-IFIT test is that the flexibility index of VRAM-containing pavement is around eight times higher than tack coat–containing pavement. Moreover, the fatigue cracking resistance of the VRAM-containing pavement is higher than the laboratory-prepared asphalt mixtures with PG 64-22, PG 70-22, and PG 76-22.

Panoramic UAV Image Mosaic Method and Its Application in Pavement Paving Temperature Monitoring

The low-altitude technology of unmanned airborne infrared detection system is used to effectively monitor the temperature segregation in the paving stage and realize the temperature uniformity control of asphalt pavement construction. The image mosaic method can splice two images with overlapping areas together to form a panoramic image. In order to solve the problems of long time-consuming and low accuracy of aerial image mosaic algorithm, the low-temperature area of the whole pavement can be obtained quickly and accurately. In this paper, threshold segmentation technology is introduced to convert the image captured by the unmanned aerial vehicle (UAV) into a binary greyscale image so as to compensate for the mosaic error caused by temperature difference. In order to improve the efficiency and accuracy of splicing, a reference plate is used, which can provide enough feature points for splicing. Finally, the image mosaic method proposed in this paper can quickly obtain the image of the whole low-temperature area of the newly paved asphalt pavement, which has practical value and positive significance for the quality control of asphalt pavement.

Rheological evolution mechanisms of asphalt binder and mastic under freeze-thaw cycles

Perennial freeze-thaw cycles have caused plenty of defects on asphalt pavements. To analyze the effect on asphalt binder and mastic under freeze-thaw cycles, the multiple stress creep recovery (MSCR) tests, frequency sweep tests, linear amplitude sweep (LAS) tests, and bending beam rheological (BBR) tests were performed first. The rheological property of asphalt binder and mastic was evaluated through the Burgers model, 2S2P1D (two springs, two parabolic elements, and one dashpot) model, Sigmoidal model, and viscoelastic continuum damage (VECD) theory. The Einstein coefficient and K.D.Ziegel−B−G∗ (K−B−G∗) model were adopted to investigate the asphalt binder-filler interaction subsequently. Finally, Fourier transform infrared spectroscopy (FTIR) test was conducted to analyze the variation of chemical composition of asphalt binder before and after freeze-thaw cycles. The results showed that as freeze-thaw cycle increased, the percent recovery of asphalt binder increased, and the non-recoverable creep compliance of asphalt binder decreased and that of asphalt mastic increased first but decreased. The rutting factor and fatigue factor of asphalt binder and mastic increased after freeze-thaw cycles. The asphalt mastic showed poorer fatigue resistance than asphalt binder at a given freeze-thaw cycle. The low-temperature stiffness of asphalt binder and mastic increased as freeze-thaw cycle increased. K−B−G∗ value showed that the asphalt binder-filler interaction damaged seriously after fifteen freeze-thaw cycles, and the Einstein coefficient decreased by 52.73% after twenty freeze-thaw cycles. The IS and IC indexes increased, and the IB index decreased after twenty freeze-thaw cycles. The design and construction of asphalt pavement in seasonal frozen regions may benefit from this study.

Statistical Approach Model to Evaluate Permanent Deformation of Steel Fiber Modified Asphalt Mixtures

A good asphalt mixture is very important to maintain the triangle of sustainability. Many accidents occur due to pavement damage such as permanent deformation caused by the external loads induced by heavy traffic. Stone Mastic Asphalt (SMA) has a low resistance to moisture and other performances. Many researchers have conducted on SMA using various types of fiber. However, not much research has been done using steel fiber in the SMA mixture and has analyzed the result obtained using a statistical approach. The objective of this research was to identify the optimum amount of steel fiber in a modified asphalt mixture and characterize the performance of steel fiber in the SMA mixture using the statistical approach of Response Surface Methodology (RSM) in Design Expert Software. In this study, various steel fiber proportions of 0 percent, 0.3 percent, 0.5 percent, and 0.7 percent by the total weight of the SMA mixture were used. The Marshall stability and flow test, dynamic creep and moisture susceptibility test, and ultimately, RSM analysis were used to evaluate the properties and performance of the steel fiber-modified SMA, which contained 6.2 percent of PEN 60/70 asphalt binder content. The testing findings unmistakably demonstrated that the addition of steel fiber greatly improves the SMA mixture’s resistance to moisture and permanent deformation. An amount of 0.3 percent was found to be the most optimum steel fiber content from the optimization by using Response Surface Methodology, thus proven with additional steel fiber in the SMA mixture enhancing the performance of the mixture. As a result, it can be determined that the addition of steel fiber to SMA asphalt mixtures has improved the properties and performance in the construction of asphalt pavements, and the RSM method is an efficient statistical method for producing an appropriate empirical model for relating parameters and predicting the best performance of an asphaltic mixture.

System Framework for Digital Monitoring of the Construction of Asphalt Concrete Pavement Based on IoT, BeiDou Navigation System, and 5G Technology

In the construction of asphalt pavement, poor quality is often the main reason for damage to the pavement, which necessitates the use of monitoring systems during the construction stage. Therefore, this study focuses on building an asphalt concrete pavement construction monitoring system to monitor the construction phase. Through a literature review and semi-structured interviews with industry experts, this paper provides an in-depth understanding of the goals and obstacles of asphalt pavement monitoring and discusses directions for improvement. Subsequently, based on the analysis of the interview results, a system framework for asphalt concrete pavement construction monitoring was constructed, and the system was successfully developed and applied to a highway construction project. The results show that the monitoring system significantly improves the construction quality of asphalt concrete pavement, improves the intelligent level of pavement construction management, and promotes the digital development of highway construction.

Application Research on Intelligent Paving Construction Technology of Asphalt Pavement Based on 3D Mechanical Control

As the major construction equipment of asphalt pavement, the performance of the paver plays a critical role in pavement construction quality, directly affecting the smoothness and compactness of the pavement, etc. Therefore, by analyzing the influence of the paver leveling method on the levelness, this project uses 3D mechanical control technology to optimize the automatic leveling method of pavers, which can improve the asphalt pavement construction process. It can also improve the quality and economic efficiency of asphalt pavement construction by increasing the automation, standardization, and wisdom of pavers.

Interlayer bonding properties of warm recycled asphalt pavements

The need for sustainable road infrastructures has led to great interest in Warm Mix Asphalt (WMA) technologies, which allow the production, lay-down and compaction of asphalt mixtures at reduced temperatures, about 40°C lower than traditional Hot Mix Asphalt (HMA). The use of WMA ensures lower emissions and is also beneficial in the recycling of Reclaimed Asphalt (RA) deriving from the milling of end-of-life pavements. One of the main concerns regarding WMA is the possible poor adhesion between the pavement layers that could be caused by the reduced working temperatures during the paving operations. However, almost no data are currently available in literature on this aspect, which thus could represent a deterrent to the wide application of WMA by road agencies. In this regard, this paper focuses on the investigation of the interlayer bonding properties of warm recycled asphalt pavements constructed along various Italian motorways and national roads using different WMA chemical additives. The Interlayer Shear Strength (ISS) was measured at different pavement interfaces (wearing-binder, binder-base) and time intervals by testing extracted cores with ASTRA and Leutner equipment. The results show that the interlayer bonding properties of WMA pavements are comparable to HMA pavements and are not affected by the WMA additive type. Moreover, ISS depends on the properties of the tack coat applied between the layers and increases over time due to aging effects, especially when the interface is below an open-graded friction course (OGFC). These findings further encourage the use of WMA as environmentally sustainable technologies for the construction and maintenance of asphalt pavements.

Optimization and Performance Evaluation of Steel Slag Asphalt Mixture Modified with Fibers under Freeze–Thaw Cycles

Recycling waste steel slag for asphalt pavement construction can reduce energy consumption and preserve nonrenewable natural resources. However, the moisture susceptibility of steel slag asphalt mixture (SSAM) in severe freeze–thaw regions should be taken into consideration. In light of this, three types of fibers (basalt fiber, polyester fiber, and lignin fiber) and rubber powder were blended into the SSAMs, and their freeze–thaw damage characteristics were investigated. First, the optimum bitumen and fiber content of SSAMs were determined based on Marshall design using response surface methodology. Then, the air voids of SSAMs were identified through X-ray computed tomography (CT) technology, while the effects of the fiber and freeze–thaw cycles on the moisture stability of SSAMs were investigated. Moreover, the enhancement effects of the fibers were analyzed using scanning electron microscopy (SEM). The results show the optimum fiber content of different fiber-reinforced SSAMs are 0.35%, 0.29%, and 0.23%, respectively, and the optimum bitumen content is 6.7% for all cases. The effect of freezing–thawing leads to an increase of the air voids in the middle part of the specimen, whereas the incorporation of fibers weakens the adverse action of freezing–thawing and effectively improves the moisture stability of the SSAMs. Furthermore, the network structure formed by basalt fibers in asphalt mastic significantly improves the integrity of the SSAM. Additionally, basalt fiber reinforced SSAM shows the best resistance to moisture damage.

Numerical analysis and conversion of dynamic and static deflection of asphalt pavement under FWD loading

During the falling weight deflectometer (FWD) evaluation, only calculating the acceptance deflection by adopting the layered elastic system theory has its limitations. In this paper, a three-dimensional finite element method was adopted to carry out the dynamic simulation analysis of typical asphalt pavement structures under FWD test. As a result, a dynamic deflection calculation model of asphalt pavement under FWD loading was established as well as the calculating method, in which a layered elastic system theory is adopted for calculations on the basis of the dynamic-static deflection ratio. Furthermore, an equivalent conversion method of asphalt pavement was proposed based on the deflection equivalent principle. Last, the applicability of the method was examined by comparing the FWD results of the pavement sections tested on-site. The method proposed in this paper to calculate the dynamic deflection of asphalt pavement is critical for the quality acceptance of asphalt pavement construction, modulus back calculation, and asphalt pavement design.

TO INCREASE THE DURABILITY OF ASPHALT PAVEMENT ON BRIDGE STRUCTURES BY USING RUBBER CRUMB

Artificial structures, which include bridges, overpasses, viaducts, overpasses and other structures, are an integral part of the transport infrastructure that meet the needs of the population in the transportation of passengers and goods. One of the main structures of a bridge structure is the bridge deck, which is the first to receive the temporary load of vehicles through the asphalt concrete pavement of the roadway. Currently, one of the methods of improving the pavement structures on bridge structures and increasing its durability is the use of the latest technologies, which involve the use of modern materials. Considering the process of construction or repair of asphalt pavement on bridge structures in the long term, special attention should be paid to the economic indicators arising from the reduction of maintenance costs, as well as significantly longer durability of the bridge deck due to the use of asphalt mixtures based on modified bitumen with rubber crumb.

A study on the effect of aging on pmb40 and crmb55 in bituminous concrete layers

Aging occurs in bituminous materials throughout the construction and service lifespan of asphalt pavement, and it has a substantial impact on their performance. Bitumen aging is one of the primary causes of asphalt pavement degradation. As bitumen ages, asphalt surfaces lose their capacity to alleviate tension during the cooling process, increasing the danger of cracking. The thin film oven test (TFOT) and the rolling thin film oven test (RTFOT) are two extensively used short-term aging tests (RTFOT). The rotating cylinder-aging test (RCAT) and pressure aging vessel are two extensively used tests in the long-term aging of bitumen (PAV). The suggested research includes the comparison of un-modified bitumen and modified bitumen of waste crumb rubber and plastic rubber. This research was conducted on the aging of different grades of bitumen, that are two modified bitumen, which are PMB40 & CRMB55. After the aging of the bitumen, we conducted some physical property tests on the normal bitumen and RTFOT-modified bitumen. The outcome of the testing of the physical properties was that the RTFOT modified bitumen gained more strength as compared to the normal bitumen after the testing of physical properties of bitumen (Normal Bitumen & RTFOT Modified Bitumen) prepared samples for testing the Marshall Properties. After testing, Marshall Properties’ research can conclude that the RTFOT Modified Bitumen provides more strength compared to the normal bitumen. The RTOFT modified bitumen can be used in rural areas to provide a better pavement surface and longevity of the pavement. Through the aging of bitumen, the adhesion property between bitumen and aggregate becomes strong, so that in a high traffic area, cracks do not develop easily

Investigation on dynamic response and compaction degree characterization of multi-layer asphalt pavement under vibration rolling

<abstract> <p>Asphalt mixture is composed of asphalt binder with aggregates of different sizes and compacted under static or dynamic forces. In practical engineering, compaction is a critical step in asphalt pavement construction to determine the quality and service life of pavement. Since the dynamic response characteristics of asphalt pavement can reflect the compaction state of asphalt mixture in the process of compaction, the establishment of the relationship between dynamic response characteristics and compaction degree is definitely significant. In this paper, a series of vibration sensors were adopted to capture the dynamic response signal of the vibration drum and asphalt mixture in the process of vibrating compaction for different surface courses of pavement. Then, the change regulations of vibration acceleration of vibrating drum and asphalt mixture were analyzed, and the quantitative linear relationship was established between accelerations of vibrating drum and asphalt pavement compactness. Further, the concept of evaluation unit (i.e., within 2 meters along the driving direction of the roller) and prediction method of compaction degree were proposed as well. The results showed that under the same vibration compaction condition, the compaction degree values of the top, middle and bottom layers have obvious differences, which should be taken seriously into consideration in the compaction process. Meanwhile, there is little difference which respectively are 2.8, 1.3 and 0.82% for the top, middle and bottom layers between the compaction degrees obtained by the proposed method and measured test. Therefore, the average value of the acceleration peak value of vibration drum within the evaluation unit can be adopted as the characterization index of the compaction degree of asphalt pavement. The investigation of this study can provide the technical reference for compaction control of asphalt pavement to a large extent.</p> </abstract>

Evaluation of Asphalt Pavement Production and Construction Processes to Determine Impact Category Based on Life Cycle Inventory

Evaluation of Asphalt Pavement Production and Construction Processes to Determine Impact Category Based on Life Cycle Inventory

Reutilization of different bamboo residue fiber as sustainable asphalt modifier: performance evaluation and parameter recommendation.

The large-scale application of bamboo has led to the production of enormous amounts of waste in the form of bamboo residue. In order to reuse the bamboo residue, three types of bamboo fiber (sinocalamus affinis fiber (SAF), green bamboo fiber (GBF), and phyllostachys pubescens fiber (PPF)) extracted from bamboo residues were studied. The properties of bamboo fiber modified asphalt were evaluated by ductility test, cone penetration test, rheologicaltest, and low-field nuclear magnetic resonance (LF-NMR) test. Furthermore, the dispersion properties of bamboo fiber were analyzed by dispersion uniformity test. The results show that the mechanical and high-temperature properties of the bamboo fiber modified asphalt are obviously improved while the low-temperature crack resistance is only slightly weakened. Meanwhile, the signal intensities of SAF modified asphaltand GBF modified asphalt are basically the same before and after aging. It proved the viscosity is not changed much, which verified the good anti-aging properties of SAF modified asphaltand GBF modified asphalt. However, PPF is the best dispersed uniformly in the asphalt. The maximum allowable length and dosage of bamboo fibers is recommended as follows: SAF (9mm, 2.0%), GBF (6mm, 1.5%), and PPF (6mm, 2.0%). The application of bamboo residue in asphalt not only emphasizes the recycling value of bamboo residue waste but also provides an optional natural fiber material for asphalt pavement construction, which meets the requirements of sustainable development.

The application of intelligent control technology for the evaluation of temperature segregation in asphalt mixture paving

The index of temperature segregation in asphalt mixture paving is one of the key indicators of quality control of asphalt pavement construction. Intelligent control techniques have also been recently used as a novel technology in controlling the temperature segregation of asphalt mixture for paving. Hence, the present study aims at developing an intelligent control system of asphalt mixture paving. Accordingly, to monitor and visualize the quality of the real-time paving, a temperature cloud was mapped for the asphalt mixture paving. Furthermore, a comprehensive evaluation method of paving temperature segregation was developed based on two indices, i.e., temperature segregation index and low-temperature area index. In addition, the accuracy of the developed system in controlling the paving temperature, thickness and segregation degree was practically confirmed. Moreover, the influence of paving temperature segregation on the asphalt pavement performance (compactness and smoothness) were practically explored. The obtained results corroborated the real-time effectiveness of the smart system in controlling the entire process of asphalt mixture paving. Also, the cloud map enabled the visual displaying of the asphalt pavement temperature segregation in real-time. Consequently, the quality of asphalt pavement construction was improved. Hence, the proposed evaluation metric was capable of accurately assess and predict the state and performance of the asphalt mixture paving temperature segregation.

Comparison of Bond Strength Evaluation Methods Between Pavement Layers

Tack coats are generally used to facilitate a bonding between pavement layers in construction of hot-mix asphalt pavements and overlays. The goal of applying a tack coat material is to ensure the new or consecutive pavement layers respond monolithically under loading and avoid premature failure caused by debonding, mat slippage, or fatigue cracking. Multiple different in-situ and laboratory tests have been developed to evaluate bond strength of tack coat materials under tension, shear, and mixed-mode loading mechanisms. However, there is no universally accepted bond strength test method or performance criteria for tack coats within the United States. While some specifying agencies have gained familiarity and comfort with a particular bond strength test, a gap exists for many states that have not adopted a testing procedure. The objective of this paper is to compare current and newly developed tack coat bond strength tests to help determine which is most indicative in predicting field performance. Field cores from four different pavement sections with varying traffic loading conditions and early bond strength performance were sampled and tested in the laboratory using four different bond strength evaluation methods. Statistical analysis of bond strength testing results shows a strong linear correlation between pull-off and shear strength testing. Meanwhile, a novel approach to tack coat bond testing under cyclic tensile loading was explored and showed appreciable discrimination between sample locations and agreement with early field performance.