Search

The expedient repair of damaged airfield pavements is important to eliminate long closure periods. Rapid-setting cement (RSC) is promising for achieving target strength in a much shorter duration (4–6 h) compared to conventional repair methods. However, when the objective is to reopen the pavement within 1–2 h, there is a lack of methods to quantify the development of mechanical properties during the first few hours. In this study, a simplified maturity method is proposed to monitor the very early-strength development of two commercially available RSC mixes with different strength development mechanisms. The results were validated using hydration chemistry data from scanning electron microscope (SEM) experiments and ultrasonic pulse velocity (UPV) tests. The experimental results show that such a maturity-based approach is effective and robust in characterizing the early-strength development of the two RSC mixes despite variations in ambient temperature conditions. [ABSTRACT FROM AUTHOR]

For road repair, a rapid method is much desired to minimize traffic disclosure. This study proposes a new method for granular materials to gain strength rapidly. Using microbial carbonation for reactive MgO cement (RMC), a pre-bio-carbonation method is proposed to allow RMC treated materials to gain 80% of the final strength in 2 h when 8% RMC content is used. In this proposed method, a biosolution that has been premixed several hours before application is applied together with RMC for soil treatment. The carbonates that have already been generated from a urea hydrolyzation using ureolytic bacteria allow an immediate carbonation of RMC. As a result, the strength of the bio-carbonated RMC treated materials gain strength rapidly due to a quick formation and crystallinity of hydrated magnesium carbonates. To study the mechanisms and effectiveness of this method, laboratory tests were carried out to evaluate the strength development with time in the RMC treated granular materials and the conditions controlling the amount of strength gain. The influence of biosolution mixing time on the strength gain and the microstructural development of the bio-carbonated RMC are also discussed. [ABSTRACT FROM AUTHOR]

In China, airports predominantly utilize airport cement concrete pavement, which inevitably undergoes deterioration in service. To uphold pavement durability and functionality, and ensure aircraft operational safety, prompt repairs of affected areas are imperative. Therefore, ordinary Portland cement mortars were used as the control group to compare and analyze the bonding performances of two common airport pavement repair materials: modified Portland cement mortars and phosphate cement mortars. Meanwhile, through microscopic experiments, the microscopic characteristics of the interfacial transition zone (ITZ) were studied, and the interface bonding mechanism was analyzed. The research results indicate that the interface bonding strength between phosphate cement mortar and old concrete pavement is the highest. This was because the elements in phosphate cement penetrated the old concrete pavement through hydration reactions, forming van der Waals forces and chemical bonding forces. In addition, the research results indicated that the presence of old concrete pavement made the three repair materials produce similar sidewall effects with the old concrete pavement, leading to a low hydration degree of the repair materials. However, the chemical bonding and penetrating structure of phosphate cement compensated for the weakening effect of the ITZ in the repair materials. [ABSTRACT FROM AUTHOR]

In maintaining roads and ensuring safety, promptly detecting and repairing pavement defects is crucial. However, conventional detection methods demand substantial manpower, incur high costs, and suffer from low efficiency. To enhance road maintenance efficiency and reduce costs, we propose an improved algorithm based on YOLOv8. Our method incorporates several key enhancements. First, we replace conventional convolutions with a module composed of spatial-to-depth layers and nonstrided convolution layers (SPD-Conv) in the network backbone, enhancing the capability of recognizing small-sized defects. Second, we replace the neck of YOLOv8 with the neck of the ASF-YOLO network to fully integrate spatial and scale features, improving multiscale feature extraction capability. Additionally, we introduce the FasterNet block from the FasterNet network into C2f to minimize redundant computations. Furthermore, we utilize Wise-IoU (WIoU) to optimize the model's loss function, which accounts for the quality factors of objects more effectively, enabling adaptive learning adjustments based on samples of varying qualities. Our model was evaluated on the RDD2022 road damage dataset, demonstrating significant improvements over the baseline model. Specifically, with a 2.8% improvement in m A P and a detection speed reaching 43 FPS, our method proves to be highly effective in real-time road damage detection tasks. [ABSTRACT FROM AUTHOR]

As the main cause of asphalt pavement distress, rutting severely affects pavement safety. Establishing an accurate rutting prediction model is crucial for asphalt pavement maintenance, pavement structure design, and pavement repair. This study explores five machine learning methods, namely Support Vector Regression (SVR), Artificial Neural Network (ANN), Gradient Boosting Decision Tree (GBDT), Random Forest (RF), and Extra Trees, to predict the development of rutting depth using data from RIOHTRack. The model's performance is measured by comparing the performance evaluation indicators of different models, such as the coefficient of determination, root mean square error, mean absolute error, and mean absolute percentage error. The results demonstrate that integrated learning techniques such as RF, GBDT, and Extra Trees works best with R2 = 0.9761, 0.9833, and 0.9747. Moreover, the GBFT model can capture the trend of the measured rutting progression curve better than the mechanistic-empirical (M-E) model. The analysis of feature importance reveals that, in addition to external factors such as temperature and axle load, the aggregate of the asphalt concrete layer and air void crucially affect rutting. The higher the base strength, the smaller the rutting depth. The proposed model is highly straightforward and serves as an accessible analysis tool for engineers in practice. [ABSTRACT FROM AUTHOR]

To investigate the structural response of emergency pavement repairs under aeroplane loading and verify the backfill material and structural applicability, two craters were backfilled. Crater 1 comprised a 2.4 m thick layer of recovered flying objects, 0.4 m of graded crushed rock (GCR), 0.2 m of roller-compacted concrete and a fibre-reinforced plastic (FRP) course. Crater 2 comprised a 2.4 m thick layer of flying objects, 0.6 m of GCR and a FRP course. Static and dynamic loads were applied using two aeroplanes. The results showed that the FRP pavement layer reduced the maximum deflection of crater 2 by 21%. Crater 1 and the concrete pavement were both slightly rigid structures with a strong load-transfer ability. The dynamic deflection basin curves of crater 2 could be fitted using a Gaussian function, while the curves of crater 1 and the concrete pavement were fitted using a quartic polynomial. Under static loading, the earth pressures of crater 2 at −0.6 m, −0.4 m and −0.2 m depths were 4.3, 9.0 and 9.6 times of those of crater 1, respectively. At a depth of −0.2 m, the earth pressure of crater 1 was 0.11 MPa, while that of crater 2 was 1.06 MPa. The results can be used to guide rapid quality inspection and optimisation design of emergency pavement repair structures and materials. [ABSTRACT FROM AUTHOR]

Transverse joints are introduced in jointed plain concrete pavement systems to mitigate the risk of cracks that can develop due to shrinkage and temperature variations. However, the structural behaviour of jointed plain concrete pavement (JPCP) is significantly affected by the transverse joint, as it creates a discontinuity between adjacent slabs. The performance of JPCP at the transverse joints is enhanced by providing steel dowel bars in the traffic direction. The dowel bar provides reliable transfer of traffic loads from the loaded side of the joint to the unloaded side, known as load transfer efficiency (LTE) or joint efficiency (JE). Furthermore, dowel bars contribute to the slab's alignment in the JPCP. Joints are the critical component of concrete pavements that can lead to various distresses, necessitating rehabilitation. The Swedish Transport Administration (Trafikverket) is concerned with the repair of concrete pavement. Precast concrete slabs are efficient for repairing concrete pavement, but their performance relies on well-functioning dowel bars. In this study, a three-dimensional finite element model (3D-FEM) was developed using the ABAQUS software to evaluate the structural response of JPCP and analyse the flexural stress concentration in the concrete slab by considering the dowel bar at three different locations (i.e., at the concrete slabs' top, bottom, and mid-height). Furthermore, the structural response of JPCP was also investigated for several important parameters, such as the joint opening between adjacent slabs, mispositioning of dowel bars (horizontal, vertical, and longitudinal translations), size (diameter) of the dowel bar, and bond between the slab and the dowel bar. The study found that the maximum LTE occurred when the dowel bar was positioned at the mid-depth of the concrete slab. An increase in the dowel bar diameter yielded a 3% increase in LTE. Conversely, the increase in the joint opening between slabs led to a 2.1% decrease in LTE. Additionally, the mispositioning of dowel bars in the horizontal and longitudinal directions showed a 2.1% difference in the LTE. However, a 0.5% reduction in the LTE was observed for a vertical translation. Moreover, an approximately 0.5% increase in LTE was observed when there was improved bonding between the concrete slab and dowel bar. These findings can be valuable in designing and evaluating dowel-jointed plain concrete pavements. [ABSTRACT FROM AUTHOR]

Patching is a common technology used in repairing asphalt-pavement potholes. Due to the differences in material properties between patched- and unpatched-asphalt mixtures, significant strain and stress concentrations could be induced; thus, further cracks and interfacial debonding distress could be caused. As a remedy, the strain and stress concentrations can be alleviated by utilizing optimum patching shapes. Therefore, this paper employed finite element methods (FEM) to deeply analyze the mechanical performance of patched-asphalt pavements embedded with different patching shapes. Three patching shapes, these being rectangular, stair, and trapezoid, were considered for use in pavement pothole repairs based on two- and three-dimensional finite element models. In the two-dimensional models, Top-Down and Bottom-Up crack propagations were simulated to assess the anti-damage performance of the patched pavements with different patching shapes. In addition, the thermal stress behaviors within patched-asphalt pavements were simulated using the two-dimensional model to analyze the performance of the patched pavements during the cooling process in construction. In addition, interface-debonding performance was simulated for the patched-asphalt pavements using three-dimensional models. In light of the simulation results, engineers are expected to better understand the mechanism within patched pavements and to improve the quality of the pavement patching. [ABSTRACT FROM AUTHOR]

The Surabaya-Gresik toll road is a crucial infrastructure connecting Surabaya City with Gresik Regency. In industrial areas such as Gresik Regency, this toll road is indeed needed to expedite the flow of industrial goods distribution to Surabaya City. The toll road experiences frequent damage, such as alligator cracking, as it is traversed daily by heavy traffic. If the road, as a connecting infrastructure, is damaged, it will impede the flow of vehicles passing through it. Therefore, road maintenance is necessary to ensure optimal service for passing vehicles. In this research, an analysis of road damage on the Surabaya - Gresik toll road seeks solutions for addressing these issues utilizing the method of Pavement Condition Index (PCI). The method involves several stages, including a survey of road conditions, determination of severity levels, assessment of damage, and determination of pavement condition. The survey was conducted in 100-meter segments from KM 10 to KM 14, revealing various types of damage on the toll road, including alligator cracking, bleeding, corrugation, shoving, potholes, and more. Thereafter, an analysis of the severity level and damage assessment was carried out, resulting in an average PCI value of 68, categorized as a "Good" condition. Based on these findings, it is recommended to address this issue through routine maintenance, including repairing minor damage, patching potholes, sweeping, repairing pavement edge damage, sidewalk maintenance, side channel and complementary building drainage, road equipment, and roadside maintenance. [ABSTRACT FROM AUTHOR]

Thermally induced stresses can build up in rigid pavements without pressure relief joints. The pressure created becomes a problem for adjacent structures such as bridges. The pressure can cause the pavement to push on the bridge and close the bridge expansion joints. This sets the stage for additional distress if not repaired quickly. This paper presents a case study where excessive pavement pressure damaged a two-span conventional bridge spanning Interstate 35 in Moore, Oklahoma. The bridge was instrumented with vibrating wire sensors to gather information on the behavior of the bridge before and after the repairs. There is a dearth of sensor verified observations of excessive pavement pressure acting on conventional bridges. The sensor data provided in-depth information on the response of the distressed bridge before and after repairs to thermal loading. Prior to the repairs the approach pavement was pushing on the bridge deck and causing the abutment backwalls to tilt toward the bridge. Following the repairs, the approach pavement is no longer pushing on the bridge deck. However, the abutment backwall is now moving in response to thermal changes in the bridge deck, likely due to excessive friction between the deck and the abutment backwall. U-shaped shaped cracking and spalling, previously observed in integral abutment bridges, was observed at this conventional abutment bridge, and the mechanisms causing these cracks and spalling are discussed. Through this study it was found that placement of pavement pressure relief joints relative to the bridge is crucial for reducing the magnitude of stress acting on the bridge. It was also found that the pavement stress acting on a bridge deck can be estimated with vibrating wire strain gauges given a baseline strain response for the approach pavement. [ABSTRACT FROM AUTHOR]

To provide a new cold patch for asphalt pavement rehabilitation. In this study, emulsified asphalt (EA) was combined with Magnesium phosphate cement (MPC) to create an organic–inorganic composite repair material with rapid repair performance. The impact of material components on the performance of the MPC-EA was investigated, the ratio range to satisfy field construction performance requirements was optimized, and field tests were conducted on a section of Liaoyang East Road in Qingdao. The results showed that the borax retarder primarily functioned to regulate the setting time of the MPC-EA and enhanced its compressive strength under test conditions. Increasing borax from 6% to 12% increased the setting time of the MPC-EA by about 80% to 97% and had an increase of about 10% on the fluidity. However, increasing the content of EA considerably delayed the setting time of the MPC-EA, while reducing its fluidity and compressive strength. Increasing A/C from 0 to 0.2 increased the setting time of MPC-EA by about 80% to 135%, reduced the fluidity by about 14% to 25%, and reduced the compressive strength of the MPC-EA by about 60% to 65%. As ambient temperature significantly affects the setting time of the material, the ratio and performance should be adjusted based on climatic conditions, disease type, and restoration needs. This study introduces a novel organic–inorganic composite material with exceptional performance for the fast repair of asphalt pavement diseases. Additionally, it provides a valuable practical example of applying MPC materials in the realm of road rehabilitation. [ABSTRACT FROM AUTHOR]

A high-performance concrete rapid patching repair material needs to develop high early strength to satisfy traffic opening requirements, yet provides sufficient durability to sustain different environmental conditions and primary deterioration mechanisms for full-depth concrete repair. In this study, a set of experiments was conducted to evaluate the performance of developed pavement repair mixtures subjected to different environmental conditions, including low ambient temperature, highly reactive siliceous aggregate, wet/dry cycling, and moisture loss. Full-scale slab patching was also carried out to assess the rapid patching mixtures' constructability, compatibility, and interface bonding with the concrete substrate. Patching materials with a reduced cement content and Type IP cement exhibited a lower drying shrinkage rate and less deterioration from wet/dry cycles compared with commonly used patching mixtures that typically use high cement content and Type I cement. The tendency of alkali-silica reaction deterioration was reduced significantly by replacing 50% Type III cement with Type IP cement. The rapid patching mixtures generally displayed a high degree of early-age shrinkage but with satisfactory compatibility and good bonding with the concrete substrate. Test results also indicate that Type III cement-based rapid patching mixtures can be a promising option to reduce traffic closure duration at lower ambient temperatures. [ABSTRACT FROM AUTHOR]

Current pavement pothole repair technology relies heavily on human experience and manual operation. To automate the repair process of pavement pothole spraying repair, a contour-guided zigzag path planning method based on depth image was proposed in this paper, including pothole slicing and slice repair path planning. In the aspect of pothole slicing, a double flood filling method was proposed to ensure the repair strategy from bottom to up under the priority of region by region, while in the aspect of slice path planning, a contour-guided round-trip repair path planning method was proposed to arrange the repair trajectory homogeneously in the pothole without exceeding its irregular boundary. The path planning results showed that the average spacing error of four kinds of common potholes with different shapes was 7.31%, the average time of the whole path planning process was 1.571 s, the average relative difference of the mean square error was only 1.83 mm, which indicated that the proposed method could obtain high path planning accuracy and fast path planning speed. The results demonstrated that the proposed contour-guided zigzag path planning method based on depth image could be applied to the automatic spraying repair of different potholes with convex or concave contours and achieve good pavement repair flatness. [ABSTRACT FROM AUTHOR]

The bonding performance between sulfur-based polymers and silicate cement mortars was evaluated in this study. A sulfur-based polymer with high strength and rapid setting properties was developed using fly ash, sand, sulfur, and rubber, without water. The correlation of sulfur and rubber contents with flexural bonding strength, as well as the correlation of the polymerization process and pore distribution with flexural bonding strength, were examined. Results revealed that a certain threshold value exists for the effect of porosity on the flexural bonding strength, and the sulfur-based polymer shows improved adhesion performance when the pore-size distribution is roughly equivalent. The incorporation of rubber particles can significantly improve the matrix compactness and increase the flexural bonding strength of sulfur-based polymers. The flexural bonding of sulfur-based polymers tended to initially increase and then decrease at the sulfur contents of 20%, 25%, 30%, 35%, and 40%, and rubber contents of 1%, 2%, 3%, 4%, and 5%. The optimal flexural bonding strength of 6.29 MPa was achieved at 30% sulfur and 2% rubber, which was close to the original flexural strength of silicate cement mortar, and the compressive strength reached 36.7 MPa. Hence, the proposed sulfur-based polymer meets some basic mechanical property requirements of road repair materials. [ABSTRACT FROM AUTHOR]

In order to meet the requirements of compatibility and timeliness of repair materials for asphalt pavement, a rapid-hardening magnesia-based cement emulsified asphalt mortar (MCAM) is prepared. The results show that high temperature or high-temperature water bath treatment reduces the stability of MCAM, and MCAM prepared from emulsified asphalt with high softening point and low water content has better high-temperature stability. Increasing the asphalt-cement (A/C) ratio decreases the dynamic stability and stiffness modulus of the MCAM-repaired asphalt mixture, but increases its failure strain, which is determined by the material properties of the asphalt and cement phases. The splitting tensile strength of MCAM-asphalt mixture specimens are all above 0.8 MPa, and the strength ratio before and after freezing and thawing is above 90%, which is significantly higher than that of traditional asphalt-based, epoxy-based and polyurethane-based pavement repair materials. When MCAM is used to repair dried surface of asphalt mixtures, its pull-out bonded strength is significantly higher than that after wet and aged treatments. In addition, the microstructure of MCAM also shows that the asphalt phase and the cement phase are mixed together, and the microstructure becomes loose as the A/C ratio increases. [ABSTRACT FROM AUTHOR]

Sand fog seal is a preventive maintenance material to repair the early distresses in asphalt pavements. The objective of this study is to develop an optimal design guideline for sand fog seal to balance the demand for rapid traffic opening with the need to keep good road performance. Based on the response surface methodology (RSM) and I-optimal methodology, the effects of the components' ratios (including water, filler, and sand) and their interactions on the curing process and surface function of sand fog seal were investigated. The test results showed that water can regulate the fluidity and dispersibility of the fresh sand fog seal mortar, but will prolong the curing process. The modified sodium bentonite, as the filler, can shorten the full curing time of sand fog seal due to its good moisture absorption and permeability. Moreover, the interaction of water and filler significantly affected the bonding strength, and the recommended water-filler ratio was 1.5. The sand content should be controlled to less than 25% to ensure good adhesion and abrasion resistance. Finally, a formulation design guideline for sand fog seal based on desirability optimization methodology (DOM) was proposed, with recommended formulation of 21.8% water, 30% filler, and 25% sand. [ABSTRACT FROM AUTHOR]

Asphalt pavement, a component of transport infrastructure, deteriorates under the influence of destructive factors. The damages which have occurred during its period of use are repaired and the asphalt pavement is recycled when its further rehabilitation is economically and technically irrational. The material from the asphalt pavement layer that has reached its limit state is milled out or broken and crushed and then is repeatedly used in the production of hot-mix asphalt (HMA) or warm-mix asphalt (WMA) mixtures. In this paper, the dynamics of the percentage recycling ratio (RR) of old asphalt pavement material was investigated. RR represents the quantity of reclaimed asphalt pavement (RAP) used in the production of HMA and WMA mixtures in Europe and the USA, divided by the total amount of RAP prepared in the country. Factors and goals affecting it are analyzed. An original system of 10 criteria that increase the RR country has been created. Decision makers do not know which factors have the maximum influence in increasing the use of RAP and this should go in connection with environmental pollution reduction and achieving economic utility. By applying different multiple-criteria decision-making (MCDM) methods and using the importance given to these criteria by 14 experts, the normalized subjective weights of the criteria were determined. Analytic hierarchy process (AHP), rank correlation, average rank transformation into weight—linear (ARTIW-L) and non-linear (ARTIW-N), and direct percentage weight (DPW) methods were used in the study. The results show that the RAP recycle rate is close to 100% in countries with a sustainable economic background. In the Baltic countries, it is mostly increased by the adequacy of regulatory documents, the strategy promoting asphalt recycling in the country, and the homogeneity and classifying of RAP. The number and capacity of RAP stocks, the number and productivity of asphalt milling equipment and the wear and tear of the asphalt pavement have the least influence on the increase in RR. The opinions of experts in assessing the significance of all criteria are consistent. The averages of the weights of criteria determined by four MCDM methods (AHP, ARTIW-L, ARTIW-N, DPW) made it possible to obtain more reliable results. These results can be used to make strategic decisions and to create a plan of practical actions to increase the RAP recycling rate in the developing countries. [ABSTRACT FROM AUTHOR]

Polyurethane (PU) cutoff walls have increasingly been used in earth dam reinforcement projects due to their excellent antiseepage properties, strong deformation capabilities, ease of construction, and environmental friendliness. However, the parameter sensitivity of earth dams with PU cutoff walls under stress–seepage field coupling has not been revealed. In this study, a three-dimensional finite-element (3D FE) model was developed based on the Jiulong Reservoir Dam prototype, and the accuracy of the model was verified through a scaled model test. Using the 3D FE model as a foundation, a series of two-dimensional finite-element (2D FE) models were then constructed to conduct a parametric study of earth dams with PU cutoff walls. The thickness, density, and position of the PU cutoff wall were selected as the sensitive factors, while the safety factor, impermeability, deformation characteristics, and von Mises stress of the earth dam and cutoff wall were selected as the evaluation indicators. The mechanical and seepage characteristics of the dam were analyzed under the condition of different sensitive factors. Furthermore, the sensitivity of the sensitive factors was ranked based on the orthogonal test program. The research results of this study can provide a theoretical basis for the optimization design method of PU cutoff walls in earth dam reinforcement projects to a certain extent. Polyurethane is a kind of building material synthesized by the chemical reaction of isocyanate and polyether. Its lightweight nature, toughness, and impressive mechanical strength make it an ideal choice for various engineering projects including but not limited to dam seepage prevention, airport pavement repair, and underground pipeline filling. This study utilizes an orthogonal experimental method to establish finite-element models of an earth dam featuring a polyurethane cutoff wall under the coupling effect of stress and seepage. By analyzing the mechanical and seepage characteristics of the dam under different sensitive factor conditions, the research results demonstrate the impact of these factors on the performance of the earth dam, providing a theoretical basis for the design method of polyurethane cutoff walls to a certain extent. [ABSTRACT FROM AUTHOR]

Annually, a great deal of money is spent repairing and maintaining pavements. As a result, several pavement experts have investigated the effects of various modifiers on pavement performance and service life. The present research evaluated the performance of a binder and asphalt mixture containing combined styrene–butadiene–styrene (SBS) (5% by binder weight) and ceramic fiber (CF) additives (0%, 2%, 4%, and 6% by binder weight). One virgin binder (AC 85/100) was used to fabricate mixtures. Several rheological binder tests and performance mixture experiments were carried out, including penetration degree, dynamic shear rheometer, rotational viscosity, ductility, softening point, four-point bending beam fatigue, wheel track, dynamic creep, resilient modulus (Mr), indirect tensile strength (ITS), linear amplitude sweep, and multiple stress creep recovery experiments. To analyze the data set, ANOVA was conducted. Rheological behavior test outcomes showed that adding compound additives led to an enhancement of high- and intermediate-temperature behaviors in bitumen. Low-temperature properties of bitumens became worse after applying ceramic fiber, whereas they were enhanced by the use of SBS. Storage stability experiments showed that utilizing ceramic fiber up to 4% improved the storage stability of binders, but as the percentages of ceramic fiber increased, phase separation of bitumens became worse. Rutting performance of binders improved with the addition of SBS and ceramic fiber. The fatigue performance of binders modified by SBS improved, whereas that of binders modified by ceramic fiber decreased. The resilient modulus and tensile strength of samples increased as CF was added up to 4%, and with the addition of more CF, the ITS and Mr decreased. Therefore, results revealed that ceramic fiber can be used as an appropriate modifier to modify the binder and mixture, and its optimum content is 4%. [ABSTRACT FROM AUTHOR]

The paper presents the results of laboratory tests and the complete results of the implementation of the Sprint fast-setting concrete technology used during the reinstallation of the concrete pavement of the DK50 road (the Młodzieszyn bypass). The problem of concrete pavement repair is related to economic and social costs and, above all, to long repair time. After an extensive analysis of various technologies, the authors created a dedicated solution, which, based on commonly existing materials, allows for a very quick repair of the existing pavement. The obtained properties of the fast-setting concrete allow the maintenance of rheological parameters for 2 h from its production and to install the mixture of the consistency of class S3/S4, while the obtained compressive strength exceeds 25 MPa within 6 h of installation. The concrete parameters obtained after 24 h show a strength exceeding 40 MPa, and after 28 days—exceeding 60 MPa. The tensile strength at shattering exceeds 5 MPa, while the tensile strength at flexural strength exceeds 7 MPa. In addition, all parameters of the fast-setting concrete meet the highest requirements currently set for newly built concrete pavement loaded by very heavy traffic. The most important parameter is the possibility to shorten the repair time of concrete pavement to one day, significantly reducing the social costs associated with closing a single lane or the entire road. An important element of the presented technology is the possibility of producing the mixture at a stationary concrete batching plant, and in the future—with the use of bags for patching potholes in road pavement. [ABSTRACT FROM AUTHOR]

Geopolymers are amorphous, quasi-crystalline, three-dimensional networked gel structures formed by the reaction of aluminosilicate raw materials and alkali activators and are composed of silicon-oxygen tetrahedrons and aluminum-oxygen tetrahedrons. They have excellent mechanical properties, durability and environmental friendliness and can be used as a substitute for Portland cement in civil engineering. In this paper, the current research achievements of geopolymers are reviewed, including the structure type, preparation process, mechanical performance, durability and application of geopolymers in civil engineering. When compared with those of ordinary Portland cement, the mechanical properties of geopolymers not only meet the specification requirements but also show carbonation resistance, acid resistance and high temperature resistance. In addition, the raw materials of geopolymers, such as fly ash and blast furnace slag, are all derived from industrial waste; the use of geopolymers can realize waste recycling, which has extremely high economic benefits. This paper introduces its applications in soil stabilization and silt solidification, curing heavy metals, pavement repair materials and so on. The shortcomings in the current research of geopolymer are also briefly analyzed. This article reviews geopolymers from multiple perspectives, trying to give a more comprehensive understanding of geopolymers. [ABSTRACT FROM AUTHOR]

Pavement maintenance is widely thought to be critical for promoting sustainability, playing a pivotal role in sustainable and resilient transportation infrastructure for growth in economic development and improvements in social inclusion. It has attracted increasing attention from both academia and industry over the past 20 years. Although several literature reviews have been conducted, there is still a lack of systematic quantitative and visual investigation of the structure and evolution of knowledge in this field. To address this lack, reported here is a comprehensive and objective scientometric analysis to visualize the status quo of research areas regarding pavement maintenance. Focusing on 614 journal articles collected from the Web of Science for 2001–2020, key researchers within the field are identified, as are the key research institutions, key countries, and their interconnections, as well as keywords, evolution trends, key publications, and citation patterns, along with the extent to which these interact with each other in research networks. Based on the in-depth analysis, a knowledge roadmap is provided to inscribe how pavement maintenance-related research evolves over time, greatly contributing to the understanding of the underlying structure of pavement maintenance, and to highlight the identified current research challenges and future research trends, thus potentially benefiting the academic community and practice field on multiple themes of pavement maintenance. The results of this research are instructive, providing a broad overview and holistic thinking for researchers and practitioners with respect to pavement maintenance research, as well as facilitating further research and applications for both academia and industry in improving pavement maintenance for sustainability. [ABSTRACT FROM AUTHOR]

To improve the efficiency of repairing asphalt pavements, a rapid-hardening magnesium-based cement emulsified asphalt (MCEA) mortar was developed. The effect of mix parameters on the properties of MCEA sample was systematically discussed, including asphalt to cement (A/C) ratio, asphalt and cement (S/(A+C)) ratio, water to cement (W/C) ratio, and MgO to phosphate (M/P) ratio, as well as the fresh properties, mechanical behavior and microstructure of MCEA sample were investigated. The results show that the initial setting time of MCEA paste is within 30 min, and the fluidity is 60–180 mm, which can effectively improve the efficiency of pavement repair engineering. Meanwhile, by adjusting the mix proportion parameters, the setting time and fluidity can be adjusted according to engineering needs. The compressive and flexural strengths of plain magnesium phosphate cement mortar reach 46.45 and 7.7 MPa, respectively, and they decrease with the increase of A/C, W/C, and M/P ratios. With the increase of S/(A+C) ratio, the area of emulsified asphalt encapsulated particles decreases, which improves the mechanical properties of MCEA mortar. Increasing the A/C ratio results in an increase in the residual MgO content and a decrease in the struvite content in the MCEA paste. Meanwhile, the residual MgO content in the MCEA paste prepared by the S-type emulsified asphalt is significantly lower than that of the N-type MCEA paste, which is related to the water content of the emulsified asphalt. In addition, the incorporation of emulsified asphalt also increases the porosity of the MCEA sample, but the N-type emulsified asphalt can play a role in refining the pore structure of the sample. [ABSTRACT FROM AUTHOR]

Copyright of DYNA - Ingeniería e Industria is the property of Publicaciones Dyna SL and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Exact Sciences is the property of Master Editora and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Pavement maintenance and repair is a crucial part of pavement management systems. Accurate and reliable pavement performance prediction is the prerequisite for making reasonable maintenance decisions and selecting suitable repair schemes. Rutting deformation, as one of the most common forms of asphalt pavement failures, is a key index for evaluating the pavement performance. To ensure the accuracy of the commonly used prediction models, the input parameters of the models need to be understood, and the coefficients of the models should be locally calibrated. This paper investigates the prediction of the rutting development of pavements with flexible overlays based on the data of the Canadian Long-Term Pavement Performance (C-LTPP) program. Pavement performance data that may be related to rutting were extracted from the survey of Dipstick for data analysis. Then, an artificial neural network (ANN) was adopted to analyze the factors affecting the rut depth, and to establish a model for the rutting development of pavements with flexible overlays. The results of the sensitivity analysis indicate that rutting is not only affected by traffic and climatic conditions, but it is also greatly affected by the thickness of the surface layer and voids in the mixture. Finally, a rutting evaluation index was provided to describe the rutting severity, and the threshold of the pavement maintenance time was proposed based on the prediction results. These results provide a basis for predicting rut development and pavement maintenance. [ABSTRACT FROM AUTHOR]

Waterborne epoxy resin (WER) emulsified asphalt (WEREA) has the advantages of high viscosity and strength of epoxy asphalt, as well as a simple construction process, so it is used widely in asphalt pavement maintenance and repair projects. This paper investigated the comprehensive properties, the microstructure, the modification mechanism, and the strength formation mechanism of WEREA. The results of bond strength tests, adhesion tests between emulsified asphalt and coarse aggregate, conventional performance tests, and multistress creep recovery (MSCR) tests showed that with the increase of WER content, the adhesive properties and creep recovery properties at high temperature of the WEREA gradually improved, and gradually became the properties of brittle materials. When the WER content was 15%, the irrecoverable creep compliance of the WEREA stabilized and it met heavy traffic demand. In addition, fluorescence microscopy (FM) and scanning electron microscopy (SEM) showed that WER changed from having an island structure to having an epoxy skeleton structure in the WEREA. The results of Fourier-transform infrared (FTIR) testing showed that during the modification of the emulsified asphalt by the WER, no new substances were generated, which indicated that the sample possessed the mechanism of intermolecular physical blending. The test results were used to analyze the strength formation process of WEREA, which provides theoretical guidance for other researchers to study WEREA. [ABSTRACT FROM AUTHOR]

Detection and measurement of cracks in asphalt pavement is one of the important tasks in transport industry to determine the quality of the pavement and submit repair requirements. In recent years, computer vision algorithms have been increasingly used to automate the solution of this problem. Therefore, researchers are faced with the acute issue of improving the accuracy of segmentation algorithms, since the safety of people depends on the timely detection of defects on the road. In this paper, ensemble methods based on Choquet and Sugeno fuzzy integrals are proposed to combine the scores of three pre-trained deep learning models: ResNet50, DenseNet169, and InceptionV3. We tested the proposed methods on a public dataset and compared the results with already-used popular ensemble methods. [ABSTRACT FROM AUTHOR]

In recent years, attention on pavement management is increasing and the research is focused on the development of innovative protocols and comparative evaluation of maintenance alternatives. Among these, the concept of sustainability related to the management of pavements is gaining ground and, more generally, infrastructure and the quantification of environmental impact as a combination of emissions and energy consumption. To properly estimate the environmental impact of different pavement interventions, a calculation methodology is presented in this paper that can summarize all the different aspects of environmental impact for both the production and paving phases of asphalt mixtures. The innovative approach takes into account also the need to evaluate new methodologies and new production processes in order to compare these new technologies with already used materials and processes. The result of this paper is a dimensionless index based on Environmental Product Declaration (EPD) certification which has been named Environmental Asphalt Rating (EAR) with weighting factors and performance coefficients fine-tuned on the European scenario. The EAR computation wants to be a certified procedure ensuring the repeatability and the quality of the environmental evaluation but also able to include in the evaluation noise and mechanical characteristics of the pavement. Several applications are expected such as the design stage of maintenance operations, and awarding criteria in tenders of monitoring phases of the pavement maintenance interventions. [ABSTRACT FROM AUTHOR]

As the most common method to detect pavement cracks, manual detection has uncontrollable factors such as low efficiency, inconsistent standards and easy to be interfered with by external forces, so it is not suitable for pavement crack detection in today's intricate traffic network. In order to improve the efficiency of pavement repair and reduce the labor cost of the repair process, this paper proposes an intelligent pavement crack detection and repair algorithm. The algorithm uses image numerical parameters to classify cracks with different geometric features and extracts texture geometric features of various types of cracks based on different filtering strategies. It solves the problem that traditional single filtering algorithms are difficult to extract features according to the different characteristics of the collected image, which leads to the loss of information. Finally, the algorithm establishes a mathematical model for efficient trajectory planning combined with the nozzle size of the crack-repairing machine. In this paper, the robustness and efficiency test of the algorithm is carried out on the pavement image dataset with various types of cracks, and the experiment is carried out on the intelligent pavement crack detection and repair prototype, which verifies the accuracy and reliability of the planned trajectory. [ABSTRACT FROM AUTHOR]

Given the importance of pavement surface, many transportation agencies have developed technical specifications to serve as a baseline for ensuring the quality of initial pavement roughness after paving works, monitoring it over time as an indicator of serviceability, and then referring to it as a threshold for strategic scheduling of pavement repair and maintenance works. Past studies have shown that various external factors are involved in determining pavement roughness; however, how principal asphaltic design parameters may affect initial pavement roughness has not been examined so far. To close this gap, this study investigated the contribution of the basic concepts of the Marshall mixture design method and individual constituent properties by analyzing the international roughness index (IRI) values of the asphalt wearing course of nine different roads with a total length of 435 km. The evidence from this study suggested that the strongest relationship at the mixture level was observed between Marshall stability and IRI, whereas optimum bitumen content had no influence on IRI. At the ingredient level, among various material properties, the specific gravity of fine aggregate was found to have the most pronounced effect on IRI. Consequently, particular attention should be devoted to these two factors to further improve IRI values at the mixture design stage. Once put into service, asphaltic pavements experience detrimental deteriorations because of repeated load-based stress and environmental conditions that result in an increase in pavement roughness. Defined as "irregularities of pavement surface," roughness is used for rating road serviceability, assessing paving quality, monitoring network condition, and optimizing investments in preservation, rehabilitation, and reconstruction of pavements. Furthermore, roughness is known to affect pillars of riding safety and driving costs. Correspondingly, most transportation agencies around the world developed technical guidelines to determine the initial roughness of the pavements newly opened to service. To improve these guidelines, more factors affecting initial pavement roughness should be uncovered. Bearing this in mind, the study presented in this paper strives to examine the comprehensive factors of asphalt design parameters and material properties to elaborate on what affects initial pavement roughness at the design level. The study results demonstrated that the strength of the paving mixture and the density of fine particles used in the mixture are of great importance for initial pavement roughness. Hence, in order to construct sustainable and cost-effective road pavements with desirable roughness, the impact of these two factors should be considered when designing asphalt mixtures. [ABSTRACT FROM AUTHOR]

Considering the poor cohesiveness of the joint between pothole repair materials on asphalt pavement and old pavement, epoxy resin (EP) was toughened in this study, and a new composite resin material applicable to pavement repair was proposed. In particular, epoxy acrylic resin was prepared through the blending modification of acrylic resin and EP. The rheological properties of the composite resin were analyzed, and the influence of different acrylic acid contents on the toughness of the composite resin was discussed. Subsequently, the curing reaction process of the composite resin was explored via differential scanning calorimetry, and the theoretical curing process was determined. On this basis, the thermal stability of the composite resin was analyzed through thermogravimetric analysis. Results show that the tensile strength, elongation at break, and impact strength of the optimal composite resin are increased by 88.43%, 4202%, and 103.14%, respectively compared with those of EP alone, indicating that acrylic resin exerts a remarkable toughening effect on EP. The construction process parameters of the resin can be effectively predicted by measuring the curing reaction degree. The onset temperature of the resin is 101 ℃, and its thermal stability is favorable and can meet the application requirements of the resin in high-temperature weather during summer. The conclusions provide an important reference for follow-up research on pavement maintenance materials. [ABSTRACT FROM AUTHOR]

The purpose of research work should be considered the practical aspects study of environmental pollution near highways with dust particles generated during repair work. The results of the study reflect the entire scope of research work carried out in order to determine the optimal composition of the concrete mixture for road repair work, which makes it possible to achieve a reduction in the emission of dust particles into the roadside environment and improve the environmental situation in the roadside. Also in this study, recommendations were proposed for the elimination of polluting factors and the elimination of negative consequences for the environment. The results and conclusions of this scientific study are of significant practical importance for road maintenance workers who professionally solve the issues of pavement repair, as well as for researchers conducting scientific research in the direction of studying environmental safety problems during road repair work. [ABSTRACT FROM AUTHOR]

Asphalt concrete pavement is gradually being adopted in cement concrete pavement repair and paving due to its short construction period and low vibration to aircraft. However, the performance of the interlayer binder is the critical factor affecting the paving effect. For the preparation of interlayer high-performance emulsified asphalt suitable for airport pavement, the type and dosage of modifier and emulsifier were taken as factors and levels for the orthogonal test. Combined with the evaporation residue, softening point, penetration, ductility, and Engla viscosity indexes, the range analysis was carried out to determine the optimal dosage of modifier and emulsifier. Furthermore, the dynamic shear rheology test (DSR), fluorescence microscope test, TG-DSC test, and shear and tensile tests were used to evaluate the technical properties of SBS/SBR modified emulsified asphalt. These results showed that the best blending mass ratio of SBS/SBR modified emulsified asphalt is 1.5% SBS + 3% SBR + 1% emulsifier. Temperature sweep at 48°C, compared with SBS/SBR modified emulsified asphalt, the complex shear modulus (G ∗) of SBS/SBR modified emulsified asphalt increased by 71% and 75%, while the rutting factor(G ∗ /sinδ) increased by 83% and 86%, respectively, which indicates that its shear deformation resistance and rutting resistance have been significantly improved. The Han curve indicates that the SBS/SBR modifier has excellent compatibility with asphalt and can maintain a stable state at a lower frequency. Before demulsification, SBS/SBR modifier and emulsified asphalt formed a stable spatial network structure. After demulsification, the continuous phase and the dispersed phase were more closely integrated, so that the emulsified asphalt exhibited better bonding performance. At different temperatures, by increasing the spraying volume, the shear and tensile strength of SBS/SBR modified emulsified asphalt increased first and then decreased. At 25°C, the maximum shear and tensile strengths are 0.86 MPa and 0.65 MPa. This study demonstrated that SBS/SBR modified emulsified asphalt formed a stable spatial network structure, giving it excellent technical properties, and can be widely used for tack coat on airport pavement. [ABSTRACT FROM AUTHOR]

Conventional hot mix plants operate to support large paving projects, making production more economic with high volume output. When repairs and maintenance are needed, it can be challenging to maintain small quantities of hot bituminous mixtures at a sufficient temperature, especially in the case of winter maintenance. Consequently, the repair materials cannot be compacted to the desired level on some occasions. This research aimed to develop a polymer modified asphalt binder with reduced temperature sensitivity for hand-laid and low-volume applications. The results showed that the highest penetration index has been achieved by modifying bitumen with 20% rubber and 2% wax. The FTIR and XRD analysis indicated that the bitumen, rubber and wax that react chemically to build 3D networks have an interlocked structure in the bitumen matrix resulting in reduced temperature sensitivity of the polymer modified asphalt binder. Furthermore, indirect tensile stiffness, permanent deformation, creep test and fatigue life test, water sensitivity and freeze-thaw cycle demonstrated an improvement in the asphalt mixture properties in terms of mechanical and durability perspectives. Overall, based on this investigation, modifying asphalt binder with 20% rubber and 2% wax resulted in stronger and durable asphalt mixture in comparison to traditional hot mix asphalt. [ABSTRACT FROM AUTHOR]

This article aims to outline the established Ground Penetrating Radar (GPR) applications for concrete pavements that are currently under development or not yet commonly applied. GPR is a non-destructive method that detects variations in the electromagnetic properties of materials, primarily the permittivity. The principles of GPR systems operation, including signal processing and data interpretation practices, are summarized in this study to review current and future uses of GPR in concrete pavement detail analysis. The use of different approaches besides GPR, makes pavement evaluation more efficient and provides more details of the material properties. In concrete pavement structure investigations, GPR technology has been utilized to detect layer thickness and rebar properties, and it also determines subsurface defects and assesses base layer conditions. In quality control studies, GPR technology is implemented for thickness and air void content measurements. Future research may include investigating GPR technique in supporting pavement designs and repair strategies. Regardless of the benefits, several limitations are reported that prevent using this technique for pavement investigation on a broader scale. The problems associated with this procedure, such as the accuracy of the method and the difficulties in interpreting recorded signals, are discussed. [ABSTRACT FROM AUTHOR]

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Materials & Technologies / Materiali in Tehnologije is the property of Institute of Metals & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, a series of controlled traffic loadings was conducted on unreinforced and geosynthetic-reinforced full-scale asphalt overlays. Unlike the common objective of using paving interlayers to mitigate the development of reflective cracks, the main purpose of adopting geosynthetics for this study was to render an increased roadway structural capacity. The project involved instrumented test sections constructed during the rehabilitation of an in-service roadway in Texas, USA. The rehabilitation involved repairing the pre-existing pavement, placing tack coat, installing a geosynthetic interlayer (except in the unreinforced section), and finally constructing a 75 mm-thick asphalt overlay. This overlay comprised a 50 mm-thick, dense-graded (TY-D) layer overlain by a 25 mm-thick, thin-overlay mixture (TOM) layer. Controlled traffic loadings were conducted, which involved driving standard and light axle loads directly above asphalt strain gauges that had been installed at mid-depth of the pre-existing asphalt layer. Comparison of tensile strains among the different test sections revealed significantly smaller tensile strains in the geosynthetic-reinforced sections compared to those obtained in the unreinforced section. Consequently, and even though geosynthetic interlayers have often been adopted to minimize reflective cracking in asphalt overlays, the field monitoring results generated in this study demonstrate that they also provide added roadway structural capacity. • Asphalt strain gauges effectively record the tensile strains under traffic loads. • The tensile strains decrease with increasing asphalt thickness. • Geosynthetic reinforcements reduce the tensile strains under standard and light axle loads. • Geosynthetic reinforcements enhance the roadway structural capacity. [ABSTRACT FROM AUTHOR]

In light of the severe hazards posed by pavement cracks on traffic safety and infrastructure longevity, the development of a convenient and effective pavement repair material has become essential. The excellent cohesive strength and resilience of PU offer significant potential as a crack repair material, ensuring enhanced durability and reliability in pavement crack repairs. This study systematically explored the workability, mechanical properties, interface bonding performance, and fracture behavior of PUM as a pavement repair material through mechanical strength tests, interfacial tensile tests, and three-point bending tests based on DIC. The results indicate that the fluidity of PUM can be adjusted through the binder-sand ratio and PD content, enabling customization for various repair scenarios. PUM demonstrates exceptional one-day compressive and flexural strengths, achieving 18.8 MPa and 7.1 MPa, respectively. Furthermore, the bond tensile strength of PUM reaches 4.3 MPa, exhibiting accelerated strength development that meets the requirements for vehicle traffic after repairs. The lower elastic modulus of PUM, ranging from 0.28 to 0.63, indicates improved deformation adaptability. SEM analysis reveals a complex interfacial bonding network between PU and aggregates, considerably enhancing the energy dissipation capacity of PUM with a peak G F value of 205.05 N/m. DIC technology robustly captured the crack progression, revealing significantly reduced stress concentration at the crack tip of PUM, with no through-thickness cracks detected during the three-point bending fracture process. It is recommended that PUM be prepared with an 80 % binder-sand ratio and 5 % PD to achieve an optimal balance of workability, mechanical, and fracture properties. • Investigated the potential of polyurethane-based mortar (PUM) as a crack-filling material for pavement repair. • The influence of binder-sand ratio and diluent content on the performance of PUM was discussed. • Utilizing the digital image correlation method to capture the crack propagation process of PUM. • The mechanical and adhesive properties of PUM were analyzed experimentally. [ABSTRACT FROM AUTHOR]

To address the challenge of sealant debonding due to cyclic temperature variations, a new pavement crack repair sealant which can achieve two-way shape memory deformation is developed. The developed crack sealant is a shape memory liquid crystal elastomer (SMLCE), designed to exhibit the deformation characteristics of heat contraction and cold expansion. First, the material composition and preparation process of the developed SMLCE are given. Thermodynamic properties, phase transition temperatures and molecular structures are analyzed based on DSC and FITR. The effects of the crosslinker and chain extender ratios and the key preparation processes on the two-way shape memory deformation and mechanical performance of SMLCE are systematically analyzed. Based on the analysis, the optimum ratio of SMLCE is determined to be 1:15 and the optimum secondary crosslinking preparation process is 150% orientation stretching. Under the optimal solution, the developed SMLCE can achieve the multiple two-way shape memory reversible deformation with a maximum 46% deformation in the temperature range of -20°C∼120°C. At the same time, the developed SMLCE has excellent mechanical properties, with a tensile strength of 20.7Mpa and an elongation at break of 322%. It also exhibits good low-temperature deformation capabilities at -10°C and above. Finally, the suitability and application potential of the developed two-way SMLCE as a pavement crack sealant are assessed. The developed SMLCE has good adaptability in most climate zones, which indicates its great potential as a pavement crack sealant. This research provides a new way for the pavement crack repair. • The developed SMLCE sealant with a two-way shape memory deformation effect. • Multiple two-way shape memory reversible deformation ability in the range of -20°C∼120°C. • Under the optimal solution, the maximum shape memory shrinkage rate reaches 47%, the tensile strength reaches 20.7 MPa, and the elongation at break reaches 322%. [ABSTRACT FROM AUTHOR]

The cold patch asphalt mixtures (CPAMs) have been manufactured by mixing the cold patch asphalt liquid (CPAL) with type LB-13 mineral mixture. The workability, Marshall stability, Freeze–thaw splitting strength and cohesion of three types of CPAMs were tested in the laboratory. The potholes were repaired using CPAMs on several sites in S101 provincial highway at Feidong. The CPAMs were sampled to measure the bulk density and Marshall stability, and the volume of air voids (VV) of those specimens was calculated. The results indicated that the Brookfeld viscosity of CPAL afected the workability of the CPAMs. The Marshall stability of three types of CPAMs was only 3.07, 3.80 and 4.28 kN, respectively. However, the CPAMs had better water stability and met the requirements of hot mix asphalt (HMA) in low-rain regions referring to JTG F40-2004. The VV decreased and Marshall stability increased with the action of the secondary compaction and the volatilization of additives. Beyond 3 months, the Marshall stability of the compacted mixtures tends to be stable. The Marshall stability of type A and B CPAMs changed from 5 to 6 kN, while that of type C CPAM varied between 4 and 5 kN. The products met the requirements of dense-graded HMA on the low-grade highway. Overall, the prepared CPAMs can be used to repair pavement potholes from the perspective of material properties and molding intensity. [ABSTRACT FROM AUTHOR]

This work addressed the issues of poor bonding and low forming strength of emulsified type cold-mix asphalt (CMA). The aim of this study was to improve the pothole repair effect. Accordingly, waterborne epoxy resin (WER) was adopted as an emulsifier, and samples of WER-emulsified CMA reinforced with polypropylene fiber were prepared in the laboratory. First, the mixing ratio of WER and curing agent was optimized through three indexes and storage stability tests. Second, fluorescence microscopy, dynamic shear rheology (DSR), and bending beam rheometer (BBR) tests were conducted to determine the ratio between WER and curing agent, called WERC, in emulsified asphalt binder. After that, pavement performance and bonding characteristics of asphalt mixes produced by this binder were evaluated to analyze the feasibility of using WER-emulsified type CMA in pothole repair and to determine the optimal WERC content. The results show that the best mixing ratio of E-44 and EH-05 is 1.5:1, and WER-emulsified type CMA mixes have shown improved strength, high-temperature rutting resistance, water stability, low-temperature crack resistance, and interfacial bonding characteristics. With the increase of WERC, the performance influence range gradually slows down. Considering overall performance improvement and cost, best WERC content is finally determined as 6.5%. The newly developed emulsified type CMA can be applied to the rapid repair of pavement potholes. [ABSTRACT FROM AUTHOR]

Airports strive to prevent safety issues, such as foreign object debris (FOD), by pavement management using the pavement condition index (PCI). The index is used in decision-making processes for overall pavement maintenance and repair, such as the prevention of additional damage due to cracks and the like. However, considering the current situation in Korea where mostly mid-sized and large commercial airports exist, problems regarding direct applications of the existing PCI deduct value have been consistently pointed out. In addition, as the relationship between the PCI and whether maintenance and repair are required is unrealistic, there have been difficulties in communication between maintenance and repair staff and decision makers. Therefore, to resolve these problems, this study first analyzed the calculation procedure of the existing PCI and then redefined the main distress type of Korean airport pavements. In addition, a deduct value curve (DVC) in terms of the severity level for six main distress factors of asphalt pavements and eight main distress factors of concrete pavements and a corrected deduct value curve (CDVC) for multiple distresses in terms of the pavement form were developed using panel rating, which is an engineering approach, by forming an airport pavement expert panel. Finally, a Korea airport pavement condition index (KPCI) was proposed using the curves, and the field application results were compared against the existing PCI to examine the adequacy of the KPCI. As a result, the developed criteria showed an overall trend lower than existing PCI. Moreover, it was verified that this trend increases with worsening pavement condition. It appears that a more discriminating evaluation may be possible when determining pavement conditions by PCI results of the developed criteria. [ABSTRACT FROM AUTHOR]