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Ultra High-Performance Concrete (UHPC) is a cement-based composite material with great strength and durability. Fibers can effectively increase the ductility, strength, and fracture energy of UHPC. This work describes the impacts of individual or hybrid doping of basalt fiber (BF) and steel fiber (SF) on the mechanical properties and microstructure of UHPC. We found that under individual doping, the effect of BF on fluidity was stronger than that of SF. Moreover, the compressive, flexural, and splitting tensile strength of UHPC first increased and then decreased with increasing BF dosage. The optimal dosage of BF was 1%. At a low content of fiber, UHPC reinforced by BF demonstrated greater flexural strength than that reinforced by SF. SF significantly improved the toughness of UHPC. However, a high SF dosage did not increase the strength of UHPC and reduced the splitting tensile strength. Secondly, under hybrid doping, BF was partially substituted for SF to improve the mechanical properties of hybrid fiber UHPC. Consequently, when the BF replacement rate increased, the compressive strength of UHPC gradually decreased; on the other hand, there was an initial increase in the fracture energy, splitting tensile strength, and flexural strength. The ideal mixture was 0.5% BF + 1.5% SF. The fluidity of UHPC with 1.5% BF + 0.5% SF became the lowest with a constant total volume of 2%. The microstructure of hydration products in the hybrid fiber UHPC became denser, whereas the interface of the fiber matrix improved. [ABSTRACT FROM AUTHOR]

Reflection cracks are one of the most common problems in semi-rigid base pavement. Setting a stress absorption layer can effectively delay the occurrence of reflection cracks, but further improvement is still needed in its interlayer bonding performance and anti-reflection crack performance. Considering the excellent crack resistance of basalt fibers and the good elastic recovery ability of rubber asphalt, it is considered worthwhile to incorporate them into traditional stress absorption layers to improve performance. To simulate the actual pavement layer effect, composite specimens consisting of a cement-stabilized macadam base + basalt fiber rubber asphalt stress-absorbing layer + AC-20 asphalt mixture surface layer were prepared to evaluate their performance through interlayer direct shear tests, interlayer tensile tests, three-point bending tests, and overlay tests (OTs). To determine the optimal fiber blending combination, four fiber lengths (3 cm, 6 cm, 9 cm, 12 cm) and four fiber proportions (120 g/m2, 140 g/m2, 160 g/m2, 180 g/m2) were selected respectively. The specific effects of basalt fibers with different lengths and dosages were analyzed. The results show that compared with the absence of fibers, the improvement of interlayer bonding performance of rubber asphalt with basalt fibers is not significant, and it has certain limitations; however, the improvement of anti-reflective crack performance is significant, with an increase of up to 305.5%. This indicates that the network structure formed by basalt fibers and rubber asphalt stress absorption layer can effectively absorb and disperse external loads, causing an excellent crack resistance effect. Meanwhile, the results indicate that the main factor affecting its interlayer bonding strength and anti-reflective crack performance is the fiber content. Based on the comprehensive analysis of the performance and economy of the stress absorption layer of basalt fiber rubber asphalt, the optimal fiber parameter combination recommended is as fiber length 9 cm and fiber content 160 g/m2. These results can provide a reference for the design and performance evaluation of basalt fiber rubber asphalt stress absorption layer, and have certain application value. [ABSTRACT FROM AUTHOR]

In order to study the effects of composite fiber on the performance of cold-mixed mixture of epoxy and SMA-10 asphalt, basalt fiber (BF) and polyester fiber (PF) codoping were carried out to analyze the effects of various composite fiber ratios on the high temperature performance, low temperature crack resistance, water stability, fatigue resistance, and aging resistance. A two-dimensional numerical model of asphalt mixture was constructed by digital image processing and discrete element simulation technology. The skeleton characteristic parameters of discrete element model were extracted to determine the optimal fiber blending length. The fiber contents were 0. 3%PF, 0. 2%PF+0. 1%BF, 0. 2%BF+0. 1%PF, and 0. 3%BF. The results show that the road performance, anti-fatigue performance and anti-aging performance of 0. 3% basalt fiber are better than that of 0. 3% polyester fiber. Among them, 0. 2%BF+0. 1%PF has the best performance improvement. Compared with single-doped polyester fiber and basalt fiber, the dynamic stability of 0. 2%BF+0. 1%PF increases from 37 058 timesµmm-1 and 42 000 timesµmm-1 to 45 000 timesµmm-1, an increase of 21. 4% and 7. 1%. The flexural tensile strength increases from 29. 01 MPa and 30. 53 MPa to 32. 08 MPa, an increase of 10. 6% and 5. 1%. The fatigue life under 650 strain condition increases from 1. 63 million times and 1. 83 million times to 1. 97 million times, indicating a increase by 20. 9% and 7. 7%, respectively. The codoping of mixed fiber in the cold mix epoxy SMA-10 asphalt mixture can improve its road performance, and the mixed effect of basalt fiber and polyester fiber is better than that of single fiber. [ABSTRACT FROM AUTHOR]

In order to study the influence of diameter on the performance of basalt fiber-asphalt mixture, AC-13 asphalt mixtures mixed with basalt fibers with diameters of 7, 16 and 25 μm were designed and prepared. Rutting test, uniaxial penetration test, low temperature trabecular test, immersion Marshall test and freeze-thaw splitting test were used to study its road performance. Ideal cracking test and dynamic modulus test were used to test its mechanical properties. The results show that the diameter of basalt fiber has a great effect on the improvement of various performance indexes of asphalt mixture. The optimum oil-stone ratio of asphalt mixture increases slightly with the decrease of basalt fiber diameter. Under the same fiber content and fiber length, the smaller the fiber diameter, the larger amount of fibers, and the richer the reinforcement network. Therefore, the 7 μm diameter basalt fiber has the most significant improvement effect on the high and low frequency dynamic modulus, medium and low temperature crack resistance and high temperature deformation resistance of asphalt mixture. The findings of the present work provides reference for the further design of basalt fiber asphalt mixture. [ABSTRACT FROM AUTHOR]

[Objective] Epoxy asphalt mixtures are primarily used in pavements of long-span steel bridge decks. The heavy load traffic and orthotropic structural characteristics of steel bridge decks require epoxy asphalt mixtures with high deformation performance, material strength, and fatigue performance. The issues encountered with epoxy asphalt mixtures include ecracking and fatigue damage. Due to the high hardness and strength of epoxy asphalt mixtures, when the steel bridge deck deforms under sea wind loads, the internal stress of the material cannot be fully transmitted. Over time, microcracks can develop within the materialunder heavy traffic and vehicle loads. This results indeclined durability and causes cracks, pits, and other deformations, leading to functional impairment of the pavement layer. Therefore, we propose incorporating fibers to enhance the cooperative deformation capacity and service life of epoxy asphalt mixtures. [Methods] In this paper, the epoxy asphalt mixture was reinforced to satisfy the requirements of anticracking, antifatigue,etc., and the reinforcing effects of different fibers (basalt fiber, glass fiber, and polyester fiber) on the epoxy asphalt mixture were studied. First, tensile tests were performed on epoxy asphalt to determine its construction temperature and elongation at break. Using the Marshall test, the mixture design of EA-10 epoxy asphalt mixtures with basalt, glass, and polyester fibers and without fiber was conducted to measure the mineral composition and optimal oil--stone ratio of the four EA-10 epoxy asphalt mixtures. The research findings revealed that the retention time and tensile strength of epoxy asphalt satisfy the engineering requirements, and the optimal oil--stone ratios of the epoxy asphalt mixture without fiber and with basalt, glass, and polyester fibers are 6.5%, 6.7%, 6.6%, and 6.8%, respectively. Second, the road performance of the four EA-10 epoxy asphalt mixtures was examined by rutting, low-temperature small beam, immersed Marshall, and freeze--thaw splitting tests. Compared with the mixture without fibers, the fibers improved high-temperature rutting and low-temperature crack resistance, and their water stability performance was also improved to a certain extent. This shows that the fibers can improve the road performance of the mixture and that the basalt fiber has the best improvement effect. Finally, the toughening effects of the four EA-10 epoxy asphalt mixtures were exploredby impact testing. [Results] The results indicated that the impact toughness at -10 °C is significantly lower than that at 15 °C. At the same time, doping fibers can improve the impact toughness of the mixture, with the impact toughness of basalt fiber being optimal. 1 The hot-mixed epoxy asphalt was subjected to viscosity tests at different temperatures (140, 150, 160, 170, 180 °C) and elongation at break tests, which showed that the construction temperature of epoxy asphalt mixtures is optimal for construction temperatures of 160-170 °C, and the construction retention time was approximately 2 h. 2 The results of the low-temperature beam bending test to study the anticracking performance of the four EA-10 epoxy asphalt mixtures showed that fiber doping can significantly enhance the anticracking performance of epoxy asphalt mixtures, and basalt fiber-doped mixtures displayed the best anticracking effect. 3 The impact test demonstrated that the impact toughness of the fiber epoxy asphalt mixture at 15 °C is better than at -10 °C. [Conclusions] This paper provides a scientific basis for guiding the application of fibers in epoxy asphalt mixtures and a reference for researching fiber toughening technologies of epoxy asphalt mixtures. [ABSTRACT FROM AUTHOR]

Because of the fast deterioration speed of the surface function of conventional asphalt pavement, thin overlayer with many advantages has been applied to the pavement surface. However, due to problems such as insufficient stripping resistance and cracking resistance, the performance of the thin overlayer needs to be further improved. To achieve this target, basalt fiber was introduced into two types of thin overlayer asphalt mixtures (Open graded friction course, OGFC-5, and Stone matrix asphalt mixture, SMA-5). The wheel tracking test and uniaxial penetration test for high temperature deformation resistance, low temperature bending beam test and indirect tensile asphalt (IDEAL) cracking test for cracking resistance, cantabro test for stripping resistance, and friction coefficient test for skid resistance were conducted to evaluate various performance of thin overlayer asphalt mixtures, along with the dynamic modulus test for dynamic mechanical response. The results showed that adding basalt fiber could enhance the high temperature deformation resistance, low temperature cracking resistance, intermediate temperature cracking resistance and stripping resistance of the thin overlayer, while having no significant impact on skid resistance. Furthermore, adding basalt fiber could increase the modulus in the high temperature region and decrease the modulus in the low temperature region of the thin overlayer asphalt mixtures, indicating thin overlayer with basalt fiber presenting superior both high temperature and low temperature performance. In addition, the evaluation indexes of SLT and SHT proposed from dynamic modulus test exhibited good consistency with the results of the performance tests. [ABSTRACT FROM AUTHOR]

Based on the Suzhou section of the Nanjing-Shanghai Expressway major and medium maintenance project, performance experiments and fatigue self-healing experiments were conducted on secondary aged asphalt to obtain indicators such as needle penetration, softening point, rotational viscosity, flow index, and self-healing index. A prediction model for the self-healing index of secondary aged asphalt based on BP neural network was also established. The comparison between the predicted results and the actual values shows that the coefficient of determination R² of the model for each type of asphalt mastic is greater than 0.9, and the sum of squared errors (SSE) is less than 0.2, indicating that the model having high prediction accuracy. This model can predict the healing index (HI) value of asphalt mastic under different conditions, providing reference for monitoring the degree of asphalt aging during the service life of asphalt pavement and selecting the timing for asphalt pavement maintenance and recycling. [ABSTRACT FROM AUTHOR]