Search Results (27)

The increasing generation of construction and demolition waste, along with the depletion of natural aggregates, has driven growing interest in recycled concrete aggregate (RCA) and reclaimed asphalt pavement (RAP) as sustainable alternatives in concrete production. However, a direct and systematic comparison between the two materials remains limited. This review addresses this gap by applying PRISMA guidelines to analyze 82 peer-reviewed studies published between 2010 and 2026. Both materials are evaluated across three key domains: physical properties, mechanical performance, and microstructural characteristics. The findings indicate that RCA can reduce compressive strength by up to 26%, mainly due to the presence of porous adhered mortar and a complex interfacial transition zone (ITZ). In contrast, RAP weakens bonding with cement paste because of its hydrophobic bituminous coating, leading to adhesive failure at the mortar asphalt interface. Despite these limitations, RCA and RAP exhibit distinct behaviors in terms of shear capacity, ductility, energy absorption, and durability. Enhancement techniques such as surface treatment, carbonation, supplementary cementitious materials, and fiber reinforcement show potential in improving performance. Additionally, life cycle and economic analyses reveal that RAP can reduce total costs and carbon emissions when efficiently processed. This study provides a unified comparative framework to support sustainable material selection and design optimization. Full article

This study investigates the blast-protective performance of RC slab strengthened on the blast face with various concrete protective layers under contact-detonation loading. The research focuses on analyzing shock wave propagation characteristics, peak pressures at measurement points, energy absorption capacities of the protective layers, the development of damage, and the governing failure mechanisms of the RC slab. The protective layers used for structural reinforcement include Steel Fiber-Reinforced Cellular Concrete (SFR-CC), Asphalt Concrete (AC), Rubberized Concrete (RBC), and Foamed Concrete (FC). Among these, the maximum support rotation angle of the structure strengthened with the SFR-CC concrete layer (T-1) is 0.20°, indicating significantly less damage and deformation compared to other protective schemes. Based on the damage coefficient calculated from the remaining sectional moment of inertia of the protected RC slabs, the destruction grades of the structures at different concrete protective schemes were classified. Among these, the SFR-CC layer exhibits the most effective attenuation of shock wave peak pressure. Additionally, the maximum support rotation angle of the structure strengthened with the SFR-CC concrete layer is 0.20°, indicating significantly less damage and deformation compared to other protective schemes. Damage grades were assigned according to a coefficient derived from the residual sectional moment of inertia of the protected RC slabs. The SFR-CC configuration (T-1) gives the lowest damage index, 0.178, approximately 64.5% below that of the NC scheme, and is classified as slight damage. In contrast to the severe damage sustained by the protected RC slabs strengthened with the NC concrete scheme, those strengthened with the AC, RBC, and FC protective layer schemes exhibit only a moderate damage grade. Empirical formulas predicting the damage index of protected structures under the combined effects of varying blast charges and concrete layer thicknesses were further developed for rapid damage assessment. Full article

In this article, the authors presented the results of research evaluating the impact of mineral wool on the properties of asphalt mixtures intended for the wearing course. The primary goal of the research was to assess the suitability of granulated mineral wool as a modifier for asphalt mixtures, improving their strength and performance parameters. The research methodology was selected in accordance with the requirements of national technical documents. The analysis of the mineral wool’s impact was conducted for AS 11 S asphalt concrete at 0.5%, 1.0%, and 1.2% by weight of the asphalt mixture. Based on the research, it was concluded that the use of mineral wool reduced the stability of the samples and increased settlement in the Marshall test, which was its only negative effect. Furthermore, the addition of 1.0% mineral wool increases the resistance of samples to water and frost by 31%, while the addition of 1.2% mineral wool increases the stiffness of asphalt concrete by 35% at a reference temperature of 5 °C and by 15% at reference temperatures of 10 °C and 15 °C. It was found that the use of mineral wool as an additive allows for a reduction in the maximum rut by up to 50% and the slope of the rutting graph by 73%. Full article

The application of carbon-fiber-based geogrids in asphalt pavements is still in the nascent phase of research in China. Compared with glass fiber, carbon fiber undergoes processes such as electrochemical surface oxidation and coating with a sizing agent (polyurethane-based) to enhance its bond strength with bitumen or concrete, and to improve its wear resistance and suitability for construction. Utilizing a suite of laboratory tests including rutting tests, low-temperature flexural failure tests, and Leutner shear tests, this study researches the impacts of surface combined body type and geogrid type on the high- and low-temperature performance characteristics and interlayer shear performance of asphalt pavement structures. The results demonstrate that carbon-fiber-based geogrid reinforcement improves the rutting and low-temperature cracking resistance of asphalt surface combined bodies, with the carbon fiber geogrid (CCF) variant exhibiting superior performance to the carbon/glass fiber composite geogrid (GCF) in both aspects. Relative to GCF reinforcement, CCF reinforcement achieves increases of 12.80–13.74%, 4.53%, and 37.47% in dynamic stability, flexural tensile strength, and flexural tensile strength enhancement rate, respectively, indicating that the polymer coating process enhances the reinforcement effect of carbon-fiber-based geogrids. Carbon-fiber-based geogrid reinforcement compromises the interlayer shear performance of asphalt pavement composites; nevertheless, CCF reinforcement delivers 13.94–28.14% better interlayer shear performance than GCF reinforcement. This indicates that the polymer coating process enhances the shear resistance at the interface of carbon-fiber-based geogrids. Surface combined body type is a key factor governing the high- and low-temperature performance and interlayer shear behavior of reinforced surface combined bodies. The dynamic stability, maximum flexural-tensile strain, and interlayer shear strength of the AC-20/AC-25 are all superior to those of the AC-13/AC-20, with respective increases of 40.25%, 27.58%, and 8.5–25.6%. The test results may provide meaningful insights into the performance behavior of geogrid-reinforced asphalt pavements. Full article

Semi-circular bending tests were conducted on high-elasticity asphalt concrete under different aging conditions to investigate the effects of rubber particles and polyester fiber contents on its fracture properties. Results showed that the incorporation of approximately 3% rubber particles increased the fracture energy by 15%, whereas the addition of 1.2% polyester fibers increased the fracture toughness and fracture energy by 4% and 19%, respectively. Aging-induced oxidative hardening enhanced the overall elastic modulus and interfacial constraint effect of the asphalt mixture, thereby improving the stress transfer efficiency among the rubber particles, polyester fibers, and the surrounding matrix. As a result, both the peak load and fracture toughness increased. However, compared with the unaged state, aged asphalt concrete became more susceptible to brittle fracture, with a decrease in fracture energy and a change in the crack propagation path from a curved to a straight trajectory. Full article

Warm-mix asphalt (WMA) technology and basalt fiber modification have been increasingly applied in road engineering. However, conventional basalt fibers often disperse unevenly and tend to agglomerate. In this study, basalt fiber powder (BFP) was incorporated into a Sasobit-based WMA system and systematically compared with matrix asphalt, Sasobit-modified WMA, conventional basalt fiber-modified WMA, and styrene butadiene styrene (SBS)-modified asphalt. Multiscale characterization—including dynamic shear rheometry (DSR), bending beam rheometry (BBR), scanning electron microscopy (SEM), and nanoindentation—was conducted to elucidate rheological behavior and interfacial micromechanical responses. The corresponding Asphalt Concrete-13 (AC-13) mixtures were further evaluated through rutting tests, low-temperature bending tests, and moisture susceptibility tests. Results demonstrate that micronized BFP achieves more homogeneous dispersion within the asphalt matrix and may promote a more effective reinforcing morphology, significantly enhancing high-temperature deformation resistance while partially mitigating the low-temperature stiffness increase induced by Sasobit. Compared with conventional basalt fiber systems, BFP shows better stress relaxation capacity and interfacial mechanical response under the tested conditions. At the mixture level, the BFP–Sasobit system showed the best overall performance, with the dynamic stability increasing by 242.2% relative to the base asphalt mixture and the residual Marshall stability reaching 92.3%, while the low-temperature flexural strain increased by 33.3%. Overall, the findings suggest that morphology-controlled micronization provides a morphology-guided enhancement strategy for Sasobit-based warm-mix asphalt by promoting coordinated improvements across the rheological, micromechanical, and mixture scales. Full article

Asphalt pavements are frequently subjected to fatigue cracking, rutting, and surface wear, which accelerate maintenance needs and shorten service life. This study evaluates the performance enhancement of NHA Class B dense-graded asphalt mixtures (12.5 mm NMAS) prepared with a 60/70 penetration grade binder through carbon fiber (CF) reinforcement. Chopped fibers (~12.7 mm) were incorporated via the dry mixing process at dosages of 0.5%, 1.0%, and 1.5% by binder weight. The results indicate that the 1.0% CF mixture delivered optimal performance, with ITS increasing by 51.9%, Marshall stability improving by 38.4%, resilient modulus rising by 42.6%, and rut depth decreasing by 69.2% compared to the unmodified control. Dynamic stability reached 33,750 passes/mm, demonstrating substantial resistance to permanent deformation. Statistical analysis using one-way ANOVA confirmed that all improvements were significant (p < 0.05). Despite a ~6.7% increase in initial cost, the CF-modified mix exhibited strong economic viability, achieving a benefit–cost ratio of 4.79 and significant life-cycle savings over 20 years. These findings underscore carbon fiber as an effective modifier for developing durable, high-performance asphalt composites with reduced maintenance requirements. This work contributes to the advancement of smart and sustainable pavement technologies for resilient transportation infrastructure. Full article

Natural fibers have attracted increasing attention as eco-friendly and sustainable additives for improving the durability and mechanical performance of asphalt mixes. This paper presents a critical state-of-the-art review of the use of six kinds of natural fibers in asphalt mixes. This paper reviews the impact of six natural fibers such as lignin fiber, bamboo fiber, bagasse fiber, corn stalk fiber, basalt fiber, and wool fiber on the properties of bitumen binders and mixes. It examines the influence of these fibers on the physical properties, rheological properties, and fatigue performance of bitumen binders. In addition, the influence of fibers on the moisture stability, anti-cracking, and high- and low-temperature performance of asphalt concrete was analyzed. The review demonstrated that the recommended lengths of natural fibers in asphalt mixes are as follows: lignin fiber 0.8–1.2 mm, bamboo fiber 4–20 mm, sugarcane bagasse fiber 5–12 mm, corn stalk fiber 3 mm, and basalt fiber 6–30 mm. Adding lignin fiber and corn stalk fiber enhanced the high-temperature characteristic of bitumen. The high- and low-temperature properties of the binder were improved by adding bamboo fiber. The addition of basalt fiber and bamboo fiber can increase rutting resistance and fatigue life. Additionally, incorporating the bamboo fiber, bagasse fiber, basalt fiber and wool fiber improved the low-temperature cracking and fatigue resistance of the bitumen mixture. The high-temperature properties of the bitumen mixes were enhanced by using basalt fibers, lignin fibers, bamboo fibers and bagasse fibers. The moisture resistance of bitumen mixes were reinforced by the incorporation of basalt fibers, lignin fibers and bamboo fibers. In general, incorporating natural fibers provided a technical method for improving the performance of asphalt concrete in road applications. Full article

Polymer modification is a well-established strategy for improving the performance and extending the service life of cementitious and other construction materials, with direct implications for environmental sustainability and infrastructure resilience. Among these polymers, polyvinylpyrrolidone (PVP), a non-ionic, water-soluble, and highly compatible polymer, has emerged as a uniquely versatile additive for mitigating degradation in aggressive environments. This review provides a critical and comprehensive synthesis of the state-of-the-art research on PVP’s roles in cement, mortar, concrete, and asphalt systems. The novelty of this work lies in its mechanistic integration and system-level interpretation, which consolidate fragmented knowledge across multiple domains—ranging from rheology and durability to nanotechnology and interfacial engineering—into a unified and coherent framework. Through cross-study comparison, this approach establishes a comprehensive understanding of PVP’s role in cementitious systems while outlining clear pathways for future research and practical implementation. This review provides the first integrated framework that connects PVP’s molecular structure, adsorption behavior, and ion-coordination mechanisms to its macroscopic influence on rheology, hydration, microstructure, and long-term durability. The review critically analyzes the underlying mechanisms, including physical pore-filling and crack-bridging, as well as chemical ion-coordination, which collectively govern PVP’s performance. Key quantitative findings are consolidated, showing that optimal PVP addition can reduce water absorption by over 35%, increase fracture toughness by ~47%, and, when used as an interfacial modifier, enhance the strain capacity of fiber-reinforced composites by over 100%. Reported benefits include improved workability, enhanced mechanical performance and toughness, superior durability under chemical and frost exposure, and the development of functional materials such as self-sensing concretes and photocatalytic coatings that support structural health monitoring and pollution mitigation. Overall, this review synthesizes current knowledge, consolidates experimental evidence in tabular form, and identifies future opportunities for leveraging PVP in the design of sustainable, low-impact, and environmentally resilient construction materials and infrastructures. Full article

Under high temperature and heavy load conditions, asphalt pavements are prone to rutting and other distress, which severely affect the service life of the road. High modulus asphalt concrete has significant advantages in addressing rutting issues in asphalt pavements. However, its low-temperature performance is often poor, especially in regions with hot summers, cold winters, and large diurnal temperature variations, which limits the application of this technology. Based on this, the study introduces three types of fibers: basalt fiber, polyester fiber, and lignin fiber as reinforcing materials to improve the performance of high modulus asphalt concrete. The effects of these fibers on the pavement performance of high modulus asphalt concrete are systematically evaluated through rutting tests, low-temperature bending tests, immersion Marshall tests, freeze–thaw splitting tests, fatigue tests, and dynamic modulus tests. The test results show that as the fiber content increases, the effect of the fibers on the high-temperature, low-temperature, and fatigue performance of high modulus asphalt concrete initially improves and then decreases. The impact on water stability is not significant, while the dynamic modulus performance decreases. Fibers can significantly improve the low-temperature performance of the mixture. Among them, basalt fiber shows the greatest improvement in high-temperature and fatigue performance, while polyester fiber provides the best improvement in low-temperature performance. The improvement effect of lignin fiber is not as pronounced as that of the first two fibers. All types of fibers have an adverse effect on the dynamic modulus of the mixture. Taking all factors into consideration, the recommended fiber contents for basalt fiber, polyester fiber, and lignin fiber are 0.4%, 0.3%, and 0.3%, respectively, as these levels exhibited the best overall performance among the discrete dosages investigated in this study. Based on the experimental results, and within the selected dosage range, a performance evaluation system for fiber-reinforced high modulus asphalt concrete is established. Full article

This paper examines the use of sheep wool and recycled aggregates (recycled concrete aggregate, reclaimed asphalt aggregate, recycled brick aggregate) in mortars. Nine cement mortars were prepared: a reference mortar with natural aggregate and no fibers, and eight mortars with 30% recycled aggregate, either fiber-free or micro-reinforced with 0.1% by mass of sheep wool fibers. The study investigates the effects of these components on the workability, mechanical properties, and microstructure of mortars. Micro-reinforcing mortars with sheep wool fibers or partially replacing natural aggregate with recycled aggregates reduces workability by up to 32%. Mortars with recycled concrete and recycled brick aggregates showed increased compressive and flexural strength compared to the reference mortar. The combined formulation (recycled brick with sheep wool micro-reinforcement) achieved the highest compressive strength, increasing by 24.3% while maintaining excellent flexural performance. Three-point bending tests with displacement control revealed improved post-crack behavior and greater ductility in fiber micro-reinforced specimens compared to those without fibers. The results support the use of sheep wool fibers in mortars, demonstrate the satisfactory performance of recycled aggregates, and indicate promising potential for formulations combining sheep wool fiber and recycled aggregate as sustainable and waste-reducing alternatives in mortars. Full article

Numerical simulation of the electrical conductivity of carbon fiber-reinforced asphalt concrete is essential for understanding its electrical behavior, yet research in this area remains limited. This study prepared six groups of Marshall specimens with carbon fiber (CF) contents of 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, and 0.6 wt%. The resistivity and asphalt concrete (AC) impedance spectra were measured to analyze the effect of fiber content on electrical performance. Nyquist diagrams were fitted to establish an equivalent circuit model, and a representative volume element (RVE) finite element model was developed. The Generalized Effective Medium (GEM) equation was employed to fit the resistivity data. The results show that the resistivity exhibits a two-stage characteristic—an abrupt decrease followed by stabilization, with an optimal CF content range of 0.2–0.4 wt%. Among the equivalent circuit parameters, the contact resistance (R₁) and tunneling resistance (R₂) significantly decreased, the growth of interface capacitance (C₁) slowed, the constant phase element Z_Q increased, and the non-monotonic change of volume resistance (R₃) reflected the heterogeneity of the internal void distribution of the material. The finite element numerical solution for resistivity, derived from the GEM equation, aligns well with experimental values, validating the proposed simulation approach. Full article

This article presents a review on the applications of basalt fibers and their composites in infrastructures. The characteristics and advantages of high-performance basalt fibers and their composites are firstly introduced. Then, the article discusses strengthening using basalt fiber sheets and BFRP bars or grids, followed by concrete structures reinforced with BFRP bars, asphalt pavements, and cementitious composites reinforced with chopped basalt fibers in terms of mechanical behaviors and application examples. The load-bearing capacity of the strengthened structures can be increased by up to 60%, compared with those without strengthening. The lifespan of the concrete structures reinforced with BFRP can be extended by up to 50 years at least in harsh environments, which is much longer than that of ordinary reinforced concrete structures. In addition, the fatigue cracking resistance of asphalt can be increased by up to 600% with basalt fiber. The newly developed technologies including anchor bolts using BFRPs, self-sensing BFRPs, and BFRP–concrete composite structures are introduced in detail. Furthermore, suggestions are proposed for the forward-looking technologies, such as long-span bridges with BFRP cables, BFRP truss structures, BFRP with thermoplastic resin matrix, and BFRP composite piles. Full article

Currently, there are limitations in the research on the use of carbon fiber geogrids to prevent low-temperature cracking in asphalt pavements. This study aims to comparatively investigate the effects of carbon fiber-based geogrid type and dense-graded asphalt concrete mixture (AC) surface combined body (SCB) type on the low-temperature cracking resistance of reinforced asphalt pavement through low-temperature bending damage tests. Two geogrid types were prepared: a carbon fiber geogrid (CCF) and a glass/carbon fiber composite qualified geogrid (GCF). Two SCB types were studied: AC-13/AC-20 and AC-20/AC-25. The results show that the improvement in the flexural tensile strength of CCF is similar to that for GCF. Moreover, under reinforced conditions, the improvement in the low-temperature cracking resistance of AC-20/AC-25 is better than that for AC-13/AC-20 by 16.26–24.57%. Based on the analysis, the reasonable ratio range of the aperture sizes to the major particle sizes in the dense gradation can achieve a more effective interlocking effect. This can improve the low-temperature cracking resistance of carbon fiber-based geogrid-reinforced samples. Then, increasing the bending absorption energy is a key way of improving the low-temperature cracking resistance of carbon fiber-based geogrid reinforcements. Eventually, the fracture type of carbon fiber-based geogrid-reinforced samples is a mixed plastic–brittle fracture. These results can provide a reference for the road failure analysis of geogrid-reinforced asphalt pavement. Full article

Designing asphalt mixtures for pavement construction by controlling the moisture-mediated damage remains challenging. With the progression of time, this type of damage can accelerate deterioration via fatigue cracking and rutting unless inhibited. In this study, two types of hot asphalt mixtures (HAMs) were made by incorporating recycled concrete aggregates (RCAs), which were reinforced with rock wool fibers (RWFs). The first specimen was a normal mixture with a completely virgin aggregate, and the second one was a sustainable mixture with 30% RCAs. The proposed mixes were thoroughly characterized to assess the impact of RWF incorporation at various contents (0.5, 1, 1.5, and 2%) on moisture resistance. The optimal asphalt concentration (OAC) and volumetric parameters of the mixes were determined using the Marshall technique. The moisture susceptibility of the obtained HAMs was evaluated in terms of the tensile strength ratio (TSR). The results revealed that the moisture resistance, Marshall stability, flow, and volumetric parameters of the HAMs were improved due to the reinforcement by RWFs, indicating a reduction in the moisture sensitivity and an increase in TSR%. In addition, the HAMs designed with 1.5% RWFs displayed the highest TSR% (11.37) and Marshall stability compared to the control mix. The observed improvement in the moisture resistance and Marshall attributes of the prepared HAMs was ascribed to the uniform distribution of the RWFs that caused a well-interconnected structure and tightening in the asphalt concrete matrix. It is asserted that the proposed HAMs can be nominated for the construction of durable high-performance pavements. Full article