Journal of Road Engineering最新文献

The filler-bitumen interaction mechanism is one of the most essential phases for comprehending the asphalt mixture's performance. However, despite numerous studies, in-depth knowledge of filler-bitumen reciprocity at a microscale level is yet to be ascertained. The goal of this research is to gain a better understanding of the filler-bitumen microscale interaction in terms of the synergy and coaction between the physicochemical and rheological performance of mastics due to filler inclusions. The rheological properties of two sustainable mastics, dolomite powder (DP) and lime kiln dust (LKD), together with a neat PEN 60/70 binder, were analysed based on a temperature sweep at elevated temperature conditions. Meanwhile, frequency sweep and multiple stress creep recovery (MSCR) tests were also conducted at pavement serviceability temperature using the dynamic shear rheometer (DSR). Physicochemical tests using a scanning electron microscope (SEM) and energy dispersive X-rays (EDX) were conducted to analyse the impact of parameters such as particle shape, grain size, texture, and chemical compositions. The DSR test results showcased how the incorporation of fillers in asphalt binder considerably improved the performance of the binder in terms of rutting and fatigue. Likewise, its strain and non-recoverable compliance parameters were substantially reduced at higher filler and binder concentrations. Physical filler attributes of low rigden voids (R.V), high fineness modulus (FM), and high specific surface area (SSA) led to greater interfacial stiffness and elasticity in LKD mastics compared to DP mastics at different loading frequencies and temperature levels. The SEM/EDX results also indicated that the elemental calcium and carbon composition of each filler component, together with its grain morphology, strongly influenced its rheological performance.

With the rapid development of asphalt pavement technology, it has attracted considerable attention to improving the durability of asphalt pavement. An effective action is to use modified asphalt with high performance and durability. Polyurethane (PU) has been used in asphalt pavement engineering to enhance the durability and service life of asphalt pavement because of its excellent high-temperature performance, toughness, wear resistance, aging resistance and oil resistance. However, PU modified asphalt technology is still in the exploratory stage. The preparation, modification mechanism and working performances of PU modified asphalt need to be further clarified. Therefore, this paper summarized the research progress of PU modified asphalt and its mixture. The composition of PU modified asphalt was introduced. The addition methods of PU materials and preparation process parameters of the PU modified asphalt were determined. The modification mechanism of PU on asphalt was discussed. The effects of polyurethane on asphalt were analyzed and the road performances of its mixture were evaluated. Finally, the development tendency towards PU modified asphalt and its mixture were forecasted.

Although there are many kinds of fracture tests to choose from in evaluating the crack resistance of asphalt mixture, the semi-circular bending (SCB) test has attracted a lot of attention in the academic road engineering community because of its simplicity, stability, and flexibility in testing and evaluation. The SCB test has become a common method to study the cracking resistance of asphalt mixture in recent years. This paper mainly summarizes the overview of the SCB test, summarizes some research results and common characterization parameters of the SCB test method in monotone test and fatigue test in recent years, and predicts and suggests the research direction of the SCB test in the future. It is found that the research on the monotonic SCB test is more comprehensive, and the research on the SCB fatigue test needs to be further improved in the aspects of loading mode, characterization parameter selection, and so on. Researchers can flexibly adjust the geometric dimensions and the test parameters of semi-cylindrical specimens, and conduct comprehensive analysis combined with the results of numerical simulation. The crack resistance of asphalt mixture can be comprehensively evaluated by fracture energy, fracture toughness, stiffness, flexibility index and other fracture indicators, combined with the crack propagation of the specimen. The analysis of numerical simulation can confirm the test results. In order to standardize the setting of fatigue parameters for future application, it is necessary to standardize the setting of bending performance.

Premature stress of cement concrete pavements is the coupled action of construction technique, structural material and environmental action. It is quite difficult to accurately get the actual stress distribution merely based on the theoretical or simulation analysis. Therefore, in-situ health monitoring is particularly significant to obtain the stress or strain information for the assessment on structural performance of cement concrete pavements. To contribute this topic, different kinds of FBG based sensors have been specially designed to measure the temperature, pressure and deformation in cement concrete pavements. A relatively long-term monitoring has been conducted to collect the effective data after the solidification of the pavement lasts for about 15 ​d. Data analysis indicates that the temperature variation inside the pavement was very stable, with maximum amplitude smaller than 2.25 °C in Sep. 2020. The longitudinal, transverse and vertical deformations of the pavement behaved in non-uniform distribution, and partial measuring points suffered from large tensile force. The concrete course had better deformation resistance than that of the soil base, and local interfacial micro void defects existed in the soil base. The preliminary results can help to understand the actual structural performance of cement concrete pavements based on the optical fiber sensing system.

Fatigue performance evaluation on asphalt mixture provides an essential reference for asphalt mixture design and pavement structure design. Laboratory fatigue test has been widely used by researchers and engineers to assess the fatigue performance of asphalt mixture, due to its low cost, high efficiency, and strong operability. To ensure performance assessment reliability, fatigue test operated in the laboratory needs to simulate the loading and environmental conditions occurring in the field asphalt layer. As a result, loading setups in laboratory fatigue tests, including loading mode, loading frequency, loading waveform, temperature, and the controlled mode, have been carefully devised by researchers. This paper reviews the above common setups in fatigue tests, which aims to illustrate the classical and latest considerations as well as ideas proposed by researchers for improving fatigue test procedures. As fatigue response data of asphalt mixture is measured from fatigue test, an analysis method is required to process the data and identify fatigue behaviors of the material. Presently, the frequently-used fatigue data analysis methods include the fatigue life model, stiffness-modulus-based method, energy-based method, and viscoelastic continuum damage (VECD) method. This paper also provides a review survey on the main concepts, indicators, and models included in those methods to facilitate their applications. Meanwhile, the latest research progress and outputs related to the four methods are also introduced and discussed to reveal the state-of-the-art developments in this research area.

As the pioneer in the intelligent construction technologies (ICT) of transportation infrastructure, intelligent compaction (IC) has been applied in the infrastructure construction of various countries. It is currently the technology that best reflects the intelligence of engineering construction. This article overviews the latest developments and trends in IC. Firstly, the basic meaning of ICT is defined based on the essential characteristics of intelligent construction of transportation infrastructure, “perception, analysis, decision-making, execution” (PADE). The concept of intelligent compaction technology classification is also introduced. The PADE requirements that intelligent compaction should meet are proposed. Secondly, according to the sequence of “perception, analysis, decision-making, execution,” the workflow and key technologies of intelligent compaction are analyzed, and the mechanism of using the response of the roller to solve the modulus is given and verified. On this basis, The IC feasibility test methods, including compaction degree, compaction stability, and compaction uniformity, are briefly described. The implementation scheme of feedback control is given. Then, the use of artificial neural networks (ANN), hybrid expert systems, and reinforcement learning in intelligent compaction are briefly introduced. Finally, several extended applications of intelligent compaction are expounded, including the development ideas of intelligent road rollers and the role of intelligent compaction in virtual construction, the layer-specific mechanical parameters of fillers, etc.

Based on the investigation of long-life asphalt pavement at home and abroad, the development of long-life asphalt pavement technology in Shandong Province, China is reviewed in this paper. The structural combination characteristics of typical long-life asphalt pavement in Shandong Province and their popularization and application are introduced. The application effect of combined base long-life asphalt pavement, which has been widely promoted, is evaluated. At the same time, taking the Binda perpetual pavement test road in Shandong Province as an example, the dynamic response and long-term performance evolution of long-life asphalt pavement are analyzed over a period of more than 17 years. Sections S1, S2, and S3 present information about full-depth asphalt pavement. Section S4 describes combined base asphalt pavement. The results show that the maximum strain of S1–S4 is within the endurance strain limit. S1, S2, S3 and S4 are all expected to be long-life asphalt pavements. In the current study, Sections S1–S4 were maintained in good condition during a service period of more than 17 years with no structural cracks and good deflection, rutting, and IRI indexes. The deflection index was stable without growth, and the IRI was also relatively stable following the opening to traffic. The rutting depth underwent a slight cumulative increase within 8 years of opening, and then stabilized. The average rutting depth over the 17-year period was less than 15 ​mm. Therefore, S1–S4 meet the design standards required for use as long-life pavements. From the perspectives of resource saving, energy saving, and emission reduction and service performance, full-depth asphalt pavement can be considered to represent a new generation of green and durable pavement structures with great future promotion potential.

Reclaimed asphalt pavement (RAP) has significant recycling value because it contains nonrenewable resources including asphalt and aggregate. However, thus far, only a small part of RAP materials can be used in the construction of recycled asphalt pavement, and the usage is regarded as a low-value utilization in the underlying layers. One of the most important reasons for this shortcoming is the problem of false particle size and pseudo gradation of RAP materials. Therefore, identifying suitable asphalt-aggregate separation technology is essential for improving the utilization of RAP materials in recycled asphalt mixture and enhancing the construction quality of recycled asphalt pavement. To address this, the paper performed a systematic review of asphalt-aggregate separation technologies for processing RAP materials and their prospects. Firstly, based on the composition of the asphalt mixture and the characteristics of RAP materials after aging, the key RAP separation technologies were proposed. Then, the concept, principle, and implementation methods of physical, chemical, and biological separation methods of RAP materials were comprehensively analyzed. Moreover, the advantages and disadvantages of various separation technologies were discussed by comparing them with the related technologies in the petrochemical industry. The application prospects of various asphalt-aggregate separation methods for RAP materials can provide a reference for upgrading and expanding solid waste recycling technology for asphalt pavement.

In this paper, the surface activated crumb rubber with waste cooking oil (WCO) was studied to improve the performance of crumb rubber modified asphalt. The activated waste crumb rubber modified asphalt (OCRMA) with different amount of crumb rubber was prepared to study the microscopic appearance of OCRMA by scanning electron microscope and fluorescence microscope and analyze the surface performance. The rheological properties and microscopic mechanism of OCRMA were characterized by dynamic shear rheological test, multiple stress creep recovery (MSCR) test, BBR test and infrared spectroscopy. The results show that the dissolution degree of waste crumb rubber is improved after WCO activation, and the compatibility with asphalt components is enhanced, and the stable cross-linking structure is formed, which improves the asphalt performance. The several new absorption peaks, which were obvious, were all caused by the composition of WCO, that is, there was no significant chemical change during the interaction between the activated crumb rubber and base asphalt. Compared with the common waste crumb rubber modified asphalt (CRMA), activation with WCO can significantly reduce the viscosity of CRMA, decrease the difference of segregation softening point by 27%, and enhance the low temperature performance by 30%. The aging degree is greatly reduced, and the anti-aging performance of OCRMA is increased by about 20% with the same dosage. The high temperature performance, though higher than that of base asphalt, decreases to some extent. After comprehensive analysis, the optimal dosage of crumb rubber for OCRMA is 30%.

During the production of palm oil, a significant amount of waste is generated. However, because of inefficient handling and utilization, these wastes are becoming a larger issue. As a result, one initiative is to use these wastes in the pavement industry as sustainable materials. However, there is still a lack of understanding about the wider incorporation of palm oil waste in asphalt pavement and its performance. This study examines existing literature on the use of various wastes in the pavement industry, including palm oil clinker (POC), palm oil fibre (POF), palm kernel shell (PKS), and palm oil fuel ash (POFA). As a result, this paper presents a systematic review and scientometric investigation of related study publications on many uses of palm oil waste in the asphalt pavement industry and its performance from 2009 to 2022. The VOSviewer application was used to conduct the scientometric study analysis. The relationship between interactions detected in co-authored country studies cited sources of co-citation, and the keyword of the co-occurrence and publication source enabled the identification of the research gap. According to the systematic literature review, 40%–60% POC can be used to fine aggregate for optimal performance, while 0–100% PKS can be used to replace coarse aggregate. In addition, 50%–80% POFA or POC fine (POCF) can be used as a filler replacement, 5%–8% POCF or POFA as a bitumen modifier, and 0.3% POF as a stabilizing additive. Furthermore, the study demonstrates that the safety of utilizing wastes with more than 50% CO₂ emissions can be curtailed with minimal heavy metal leaching and radioactivity levels. The scientometric analysis may encourage researchers to seek out gaps in the literature that will aid in the long-term, multifaceted use of palm oil wastes in the asphalt pavement industry. Furthermore, the study recommends employing and researching the enormous potential of using palm oil waste in the pavement sectors because they are more sustainable and have better performance. However, there are some barriers to using palm oil waste in the asphalt pavement industry, such as a lack of design standards and guidelines, inefficient raw material processing conversion facilities, and large-scale production equipment.