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Many researchers use fiber to improve the cracking resistance of asphalt mixtures, but research concerning the effects of fiber on fracture behavior is limited. The fracture behavior of asphalt mixtures with various fiber types (basalt fiber, glass fiber, and polyester fiber) and contents (0.1%, 0.2%, 0.3%, 0.4%, and 0.5%) has been studied using the indirect tensile asphalt cracking test (IDEAL-CT) in conjunction with digital image correlation (DIC) technology. The evaluation indexes used in the test included crack initiation energy (Gif), crack energy (Gf), splitting tensile strength (RT), cracking tolerance index (CTindex), and the real-time tensile strain (Exx) obtained using digital image correlation technology. The results showed that despite the fiber type, the increase of fiber content resulted in first, an increase, and then, a decrease of the cracking resistance of asphalt mixtures, indicating the presence of optimum fiber content—specifically, 0.4%, 0.3%, and 0.3% for basalt fiber, glass fiber, and polyester fiber, respectively. The development of real-time tensile strain, obtained based on digital image correlation technology, could be divided into two stages: slow-growth stage and rapid-expansion stage. In addition, asphalt mixture with basalt fiber presented the best cracking resistance at both the slow-growth and rapid-expansion stages. This research is helpful in understanding the effects of fiber type and content on the fracture behavior of asphalt mixtures and has certain reference significance for the application of fiber in asphalt mixtures. [ABSTRACT FROM AUTHOR]

Glass fiber reinforced polymer (GFRP) is the main composite material used in wind turbine blades. In recent years, zero-carbon energy sources such as wind power have been widely used to reduce carbon emissions, resulting in a large amount of waste GFRP, and causing serious environmental problems. To explore efficient ways to recycle waste GFRP, this study explores the impact of adding GFRP powder (nominal maximum particle size ≤ 0.075 mm) on the high and low temperature properties of asphalt mastic. Samples of GFRP asphalt mastics were prepared with filler-asphalt mass ratios of 0.01:1, 0.1:1, 0.8:1, and 1:1, as well as two control samples of limestone filler asphalt mastics with filler-asphalt mass ratios of 0.8:1 and 1:1. The study analyzed the effect of GFRP on the asphalt mastic's performance using temperature sweep, MSCR, and BBR tests. Results showed that the presence of GFRP improved the high-temperature resistance and recovery of asphalt mastic but led to decreased low-temperature crack resistance. The results suggest that GFRP has the potential to be used as a filler in asphalt mastic, with a recommended filler-asphalt mass ratio range of less than 0.8:1 for optimal low-temperature performance. However, further research is necessary to determine the optimal content of GFRP in asphalt mastic and to study its impact on other road performance metrics. [ABSTRACT FROM AUTHOR]

Pavement design is a long-term structural analysis that is required to distribute traffic loads throughout all road levels. To construct roads for rising traffic volumes while preserving natural resources and materials, a better knowledge of road paving materials is required. The current study focused on the prediction of Marshall stability of asphalt mixes constituted of glass, carbon, and glass-carbon combination fibers to exploit the best potential of the hybrid asphalt mix by applying five machine learning models, i.e., artificial neural networks, Gaussian processes, M5P, random tree, and multiple linear regression model and further determined the optimum model suitable for prediction of the Marshall stability in hybrid asphalt mixes. It was equally important to determine the suitability of each mix for flexible pavements. Five types of asphalt mixes, i.e., glass fiber asphalt mix, carbon fiber asphalt mix, and three modified asphalt mixes of glass-carbon fiber combination in the proportions of 75:25, 50:50, and 25:75 were utilized in the investigation. To measure the efficiency of the applied models, five statistical indices, i.e., coefficient of correlation, mean absolute error, root mean square error, relative absolute error, and root relative squared error were used in machine learning models. The results indicated that the artificial neural network outperformed other models in predicting the Marshall stability of modified asphalt mix with a higher value of the coefficient of correlation (0.8392), R2 (0.7042), a lower mean absolute error value (1.4996), and root mean square error value (1.8315) in the testing stage with small error band and provided the best optimal fit. Results of the feature importance analysis showed that the first five input variables, i.e., carbon fiber diameter, bitumen content, hybrid asphalt mix of glass-carbon fiber at 75:25 percent, carbon fiber content, and hybrid asphalt mix of glass-carbon fiber at 50:50 percent, are highly sensitive parameters which influence the Marshall strength of the modified asphalt mixes to a greater extent. [ABSTRACT FROM AUTHOR]

Using of Reclaimed Asphalt Pavement (RAP) has been become indispensable in most of the world nations as for its many benefits as significant cost savings and provide environmental benefits. Many factors such as virgin materials, binder content, availability of RAP, viscosity of binder and extent of deterioration had important role in effecting on Optimum percentage of RAP. In this study, effect of using RAP on the asphalt mixture properties and the its optimum ratio was determined to achieve the objective of the study. The glass fiber (GS) was used as additives to improve the asphalt mixture. It has been observed from the previous researches that the optimum percentage of reclaimed asphalt use is not determiner and is disagreed from project to project. So, different percentages of RAP was (25%, 50%, 75%, 100%) by weight of aggregate were added as well as using the additive GS at optimum bitumen content. The study is revealed that untreated 100% RAP materials are not good as a bituminous mix. and was showed that mix prepared with 25% RAP gave nearly the same physical and strength parameters as virgin bituminous mix. From results of study, the use of RAP until (%50) as a maximum percentage in unmodified asphalt mixture course sustained good results. To achieve better performance, the percentage of 25% RAP was used with percentage of 0.26% GS. This mix achieved the specification requirements and ensured the degree of better performance for paving. The economical evaluation of using percentage of 25% RAP with percentage of 0.26% GS was also studied. The results indicated that, about 21% of the cost was saved. [ABSTRACT FROM AUTHOR]

Waste Fiber-Reinforced Polymer (FRP) composites have become an environmental issue in China, Europe, and the United States. However, recycling waste FRP composites poses sustainability challenges in the long term because their predominantly cross-linked structure (thermoset matrices coating) typically cannot be re-used or re-processed. Here, for the first time, we studied the merits of introducing recycled glass fibers (rGF) to bitumen to enhance bitumen's durability as measured by resistance to aging and resistance to moisture damage. We compared the reinforcement efficacy of recycled glass fibers (rGF) with recycled glass fibers after the polymer coating was removed (rGFWP) and with virgin glass fibers (vGF). After aging, compared to the bitumen with rGFWP, the bitumen containing rGF showed enhanced resistance to oxidative aging, as evidenced by lower values of two indexes of chemical aging (a 64.5% lower carbonyl index and a 94.5% lower sulfoxide index), a 47.10% lower increase in the ratio of large molecular size, and a 61.41% lower rheological aging index. Moreover, bitumen containing recycled glass fiber demonstrated noticeably improved resistance to moisture damage as compared to base bitumen, particularly for rGFWP, as demonstrated by energy ratio (ER) values that were 478% higher. The resistance to moisture damage of bitumen containing rGF was also significant improved, as evidenced by a 72.78% increase in surface energy, the better MISTI value (the least variation from a value of one), and a 213% higher ER value compared to base bitumen. This indicates that recycled glass fibers have positive effects on the durability of bitumen composites. The outstanding durability of bitumen with recycled glass fibers highlights the feasibility of adding recycled glass fibers to bitumen as a practical application that provides an economic and environmentally friendly solution for waste glass fibers. Use of recycled glass fiber in bitumen enhance its durability and delays aging. [Display omitted] [ABSTRACT FROM AUTHOR]

Open-Graded Friction Course mixture (OGFC) has a gap-graded aggregate that results in highly air voids. This structure provides higher permeability by allowing water to flow through it. Although these mixtures have good drainage properties, they exhibit poor strength with a short life span. Because of their poor performance, there is a lack to be used in pavement application. Attempts had made to increase mixture performance; one of these methods is by using fibers or polymers. The objective of the current study is to determine if modified OGFC mixes with different polymers and fibers have comparable performance. Polymers and fibers were used in OGFC mixes to evaluate their performance. Steel fiber, glass fibers, Polyvinyl chloride (PVC) and Phenol resin were investigated in this study. The modified mixtures were tested by indirect tensile strength, Marshall and permanent deformation tests. Results showed that fibers decrease rutting by 19% and they have more effective than polymers that decrease rutting by 7%, and glass fiber was found to be more effective with a 24% reduction in permanent deformation than other additives to enhance performance. [ABSTRACT FROM AUTHOR]

• Effect of RAP and glass fiber on fracture behaviors of UTFC were investigated. • The size-independent fracture energy was obtained considering the tail part of the load–displacement curve. • Two new parameters, cracking resistance index and balanced cracking index, were adopted to characterize the fracture performance. Ultra-thin friction course (UTFC) presents excellent performance in preventative maintenance of asphalt pavement. UTFC could be also used as the wearing course of newly constructed pavements. This study investigated the effects of reclaimed asphalt pavement (RAP) and glass fiber on the fracture behaviors of UTFC at the low and intermediate temperatures. At the low temperature (-10℃), fracture energy, stress intensity factor and cracking resistance index (CRI) were obtained to present the fracture behaviors of three types of UTFC mixtures. At the intermediate temperature (25℃), the size-independent fracture energy considering the tail part of the load–displacement curves were obtained. Besides, J-integral, cracking resistance index (CRI) and balanced cracking index (BCI) were obtained to characterize the intermediate fracture performance. Results indicated that at −10 ℃, the incorporation of RAP weakened the fracture resistance of UTFC; while the addition of glass fiber could counteract the adverse effect of RAP. Besides, CRI value of UTFC with glass fiber was the largest, indicating the superior fracture resistance at the low temperature. At 25 ℃, UTFC presented the best cracking resistance in terms of fracture energy, J-integral, CRI values and BCI values, indicating the incorporation of RAP could deteriorate the fracture resistance at the intermediate temperature. When both RAP and glass fiber were added in UTFC, the fracture performance was deteriorated furtherly, which may be possibly caused by the non-uniform distribution of fiber. On the other hand, the bonding strength between fiber and asphalt could be mitigated when temperature increased from −10 ℃ to 25 ℃. The size-independent fracture energy of UTFC was the largest, indicating the superior fracture resistance, followed by UTFC-50% RAP-F and UTFC. It was also reported that the incorporation of fiber improved the ability to tolerate deformation. [ABSTRACT FROM AUTHOR]

Fiber Reinforced Polymer (FRP), especially glass fiber reinforced polymer (GFRP), has been widely used in construction, navigation, transportation, and chemical engineering due to its excellent physical and mechanical properties. As a result, a great amount of waste GFRP is produced which leads to serious environmental pollution, and an efficient treatment method of waste GFRP is urgently needed. In this research, the waste epoxy-based GFRP composite powder was recycled as an mineral filler alternative for the fabrication of asphalt mastics, and the properties of the GFRP powder asphalt mastics were investigated. The results show that the waste GFRP powder has a greater specific surface area and lower density than limestone fillers. The regular cylindrical particles in GFRP powder are found to show an anti-put-off effect which improves the medium and high-temperature performance, rutting resistance, and fatigue resistance of asphalt mastics. However, the lower density of waste GFRP powder, which takes up a higher volume ratio in asphalt mastics compared with limestone filler at the same mass ratio, has negative effects on the low-temperature performance of asphalt mastics. Waste GFRP powder can also improve the aging resistance and moisture resistance of asphalt mastics. This research provides a feasible solution for the recovery of GFRP waste with low energy consumption and pollution production. It also contributes to the sustainable development of pavement infrastructure construction. • The broken glass fiber show an anti-put off effect in asphalt mastics. • GFRP asphalt mastic has great high-temperature performance and fatigue resistance. • Waste GFRP powders can improve the aging and moisture resistance of asphalt mastics. • The positive effect of waste GFRP powder is due to its special microstructure and physical properties. [ABSTRACT FROM AUTHOR]

Lignin and glass fiber were used as additives to improve the quality of road pavements and minimize moisture damage and cracking at low temperatures on asphalt pavement, according to a previous laboratory study. The aim of this paper is to make a significant contribution to the environmental assessment of the construction of road pavements using four types of asphalt mixtures based on the life cycle assessment (LCA) methodology according to the requirements of ISO 14040, considering the impact of raw material extraction, asphalt mixture manufacturing, transportation, and wearing surface construction. The results of the environmental assessment showed that all studied asphalt mixtures do not offer any improvement in all impact categories, and three modified asphalt mixtures have a slight negative effect in all impact categories. The composite mixture has the highest negative effect of the studied three modified asphalt mixtures in all categories except in the marine aquatic ecotoxicity potential category and freshwater aquatic ecotoxicity potential category, where the lignin modified asphalt mixture has the highest negative effect in these two categories but has the best environmental impacts on most of other impact categories. Furthermore, the negative effect caused by composite asphalt mixtures is minimal and thus can be used to improve the overall performance of asphalt pavement. [ABSTRACT FROM AUTHOR]

This paper presents details of a large field trial and some observations conducted to evaluate the practical efficiencies of geosynthetically reinforced asphalt pavements in Shanxi Province, China. Three glass-fiber grids (LB2000 II, TGG-8080, GGA 2021), one plastic grid (Tensar AR1), two geotextiles (nonwoven needle-punched and nonwoven heat-bonded), and one geocomposite (Tensar AR-G) application were selected for evaluation. These geosynthetics were installed in the interface between new asphalt pavement layers (APL) and new cement-stabilized gravel–sand base courses coated by emulsified asphalt or within new APL in the reconstruction of asphalt pavement sections (Program I), or in the interface between old APL and new overlay layers in the asphalt overlay pavement sections (Program II). In each program, reinforced sections with different geosynthetics were compared with each other and with nonreinforced sections to determine relative performance. Inspections after construction showed that the integrated damage ratio and deflection in the pavement sections reinforced with glass–fiber grids were less than other pavement sections. Furthermore, after about 4 years of service, glass-fiber grids were dug out and no breaking and node movement were discovered. Nevertheless, observations indicated that geosynthetics may not be effective, if bearing capacity of the base course/subgrade is inadequate, or if the overlay thickness is too thin, or if preconstruction repair of distressed old pavement is incomplete. [ABSTRACT FROM AUTHOR]

Nowadays, in order to improve asphalt pavement performance and durability and reduce environmental pollution caused by hydrocarbon materials, many researchers are studying different ways of modifying asphalt concrete (AC) and finding alternative paving materials to extend the service life of pavements. One of the successful materials used in the modification of AC is fibers. Different types of fibers have been reinforced in AC mixtures and improvements have been observed. This research studies the performance of glass wool fibers reinforced in a dense-graded asphalt mixture. Generally, glass fibers are known to have excellent mechanical properties such as high tensile modulus, 100% elastic recovery and a very high tolerance to heat. Glass wool fibers are commonly used as a thermal insulation material. In this research, to evaluate the performance of glass wool fibers in AC, laboratory tests, the Marshall mix design test, indirect tensile strength (IDT), tensile strength ratio (TSR) and the Kim test were conducted to determine a proper mix design, tensile properties, moisture susceptibility, rutting and fatigue behaviors. Results show that the addition of glass wool fibers does affect the properties of AC mixtures. The use of glass wool fibers shows a positive consistence result, in which it improved the moisture susceptibility and rutting resistance of the AC. Additionally, results show that the addition of fiber increased tensile strength and toughness which indicates that fibers have a potential to resist distresses that occur on a surface of the road as a result of heavy traffic loading. The overall results show that the addition of glass wool fibers in AC mixtures is beneficial in improving properties of AC pavements. [ABSTRACT FROM AUTHOR]