Search Results (10)

Steel bridge deck pavements (SBDPs) are susceptible to complex mechanical and service environmental conditions, yet current design methods often struggle to simultaneously capture global bridge system behavior and local pavement responses. To address this issue, this study develops a multi-scale finite element modeling framework that integrates a full-bridge model, a refined girder-segment model, and a detailed pavement submodel. The framework is applied to an extra-long suspension bridge to evaluate the mechanical responses of five typical pavement structural configurations—including double-layer SMA, double-layer Epoxy Asphalt (EA), EA-SMA combinations, and a composite scheme with a thin epoxy resin aggregate overlay. By coupling global deformations from a full-bridge model to the local pavement submodel, the proposed method enables a consistent assessment of both bridge-level effects and pavement-level stress concentrations. The analysis reveals that pavement structures significantly alter the stress and strain distributions within the deck system. The results indicate that while the composite configuration with a thin overlay effectively reduces shear stress at the pavement–deck interface, it results in excessive tensile strain, posing a high risk of fatigue cracking. Conversely, the double-layer EA configuration exhibits the lowest fatigue-related strain, demonstrating superior deformation coordination, while the optimized EA-SMA combination offers a robust balance between fatigue control and interfacial stress distribution. These findings validate the effectiveness of the multi-scale approach for SBDP analysis and highlight that rational structural configuration selection—specifically balancing layer stiffness and thickness—is critical for enhancing the durability and long-term performance of steel bridge deck pavements. Full article

Ultra-thin overlays (UTOL) are a standard highway pre-maintenance method used to improve the road surface performance of asphalt pavements and to repair minor rutting and cracking. However, the thin thickness makes it very sensitive to external changes, which increases its wear and shortens its life. So, this paper aims to prepare a durable and skid-resistance asphalt ultra-thin overlay using epoxy asphalt (EA) and steel slag. First, the physical properties of EA were characterized by penetration, softening point, flexibility, and kinematic viscosity tests. The dynamic shear rheometer (DSR) test characterizes EA’s rheological properties. Differential Scanning Calorimetry (DSC), kinematic viscosity, and Fourier transform infrared spectroscopy (FTIR) characterized the EA’s curing process. Finally, the pavement performance of an epoxy ultra-thin overlay (EUTOL) prepared with EA and steel slag was tested. The results show that the epoxy resin particles increase with the increase in epoxy resin dosage, and at 40%, its epoxy particles are uniformly distributed with the most significant area share. With the addition of epoxy resin, the needle penetration of EA decreases and then increases, the flexibility decreases at a slower rate, and the softening point rises significantly. Moreover, the growth of the elastic component in EA significantly improved the high-temperature viscoelastic properties. Considering its physical and rheological properties, the optimal doping amount of 40% was selected. By analyzing the curing behavior of EA (optimum dosage), the combination temperature of EA is 150 °C, which meets the needs of mixing and paving asphalt mixtures. After 12 h of maintenance at 120 °C, its reaction is sufficient. The skid-resistance durability, high-temperature, low-temperature, water stability, and fatigue resistance of UTOL can be effectively improved using steel slag coarse aggregate. Full article

When exposed to sun radiation and heat, asphalt binders age, resulting in reduced flexibility, cracking, and pavement failure. Given the increasing demands of traffic, environmental concerns, and resource scarcity, highway agencies and researchers are actively seeking solutions that meet performance requirements and demonstrate awareness of using non-renewable resources. Epoxy asphalt (EA) promotes sustainability concepts due to its production at significantly lower mixing and compaction temperatures, enhanced durability, improved serviceability, reduced maintenance needs, and successful recycling and reuse in hot asphalt mixtures. Crumb rubber, a widely recognized recycled waste tire material, is considered a viable option for promoting sustainability and enhancing asphalt binder properties. This study aims to enhance the durability and long-term performance of asphalt binders by utilizing sustainable materials. Six types of asphalt binders were employed: PG 67-22 base asphalt binder; styrene–butadiene–styrene (SBS)-modified PG 76-22 and PG 88-22H (3.5% and 7.0% dosage rates, respectively); a hybrid PG 76-22CS-modified asphalt binder prepared with SBS and crumb rubber modifiers; and 25EAB and 50EAB epoxy-modified asphalt binders prepared at 25 and 50% dosage rates, respectively. Results indicate that the sustainable asphalt binders PG 76-22CS, 25EAB, and 50EAB demonstrated comparable or superior performance compared to SBS-modified asphalt binders, as measured by rutting and fatigue factors. Additionally, epoxy asphalt binders had better anti-aging and cracking resistance, as shown by the outcomes of Fourier-transform infrared spectroscopy and linear amplitude sweep tests, respectively. This study contributes valuable insights into the potential of sustainable materials to enhance the overall performance and resilience of asphalt binders. Full article

Although research shows that waterborne epoxy resin emulsified asphalt (WER-EA) is an environmental protection material with potential high resistance to multiple types of pavement distress, its performance is rather complicated and much affected by the curing agent and epoxy resin value. This paper serves as a follow-up study to the preliminary published research on evaluating the impact of the epoxy value and common curing agents on the performance of asphalt mixtures. Four groups of emulsified asphalt were filtered out to prepare mixture samples, and laboratory tests on mixture performance under high and low temperatures were conducted. Specifically, Marshall and rutting tests were conducted for evaluating mixture resistance to rutting under high temperatures, and indirect tensile tests were conducted to indicate resistance to cracking at low temperatures. Water stability performance was also assessed by comparing the mixture properties before and after water absorption. The results showed that the mixture with an epoxy value of 20 and curing agents using triethylenetetramine (TETA) had the best overall performance among the investigated mixtures, with the highest resistance to high-temperature deformation and water damage. However, more research should be conducted to improve the low-temperature resistance to cracking for WER-EA mixtures. Full article

To investigate the effects of epoxy resin at low content on the physical properties, rheological properties, and self-healing properties of asphalt, epoxy asphalts with epoxy resin contents of 2%, 5%, 10%, and 20% were prepared. The distribution of epoxy asphalt (EA) in epoxy resin (ER) was quantitatively studied by fluorescence microscopy (FM) to investigate the feasibility of the preparation process. The glass transition temperature of epoxy asphalt was quantitatively analyzed by the differential thermal analyzer (DSC). The physical properties of epoxy asphalt were characterized by penetration test, ductility test, and softening point test. The rheological properties of epoxy asphalt were analyzed by the dynamic shear rheometer (DSR) to evaluate the self-healing properties of epoxy asphalt. The results show that the epoxy resin could be uniformly distributed in the asphalt, as verified by fluorescence microscopy (FM). With the increase in epoxy resin content, the glass transition temperature of epoxy asphalt gradually decreases, and the epoxy asphalt with 20% content shows the lowest glass transition temperature. At the same time, epoxy resin gives asphalt a higher modulus and high temperature performance, and the penetration and softening point of epoxy asphalt has also been greatly improved. On the contrary, the three-dimensional cross-linked grid structure, which is formed by epoxy resin and curing agent, reduces the rheological properties of epoxy asphalt and increases the elastic components of epoxy asphalt. Although the maltenes diagram still exhibits typical viscoelastic characteristic, the flow behavior index and flow activation energy of epoxy asphalt decreased. Full article

To solve the problem of the insufficient anti-slip performance of steel bridge deck wear layers, a kind of new epoxy asphalt mixture FAC-10 (Full Epoxy Asphalt Content is shortened to FAC) is proposed in this paper based on the design method of an asphalt-rich mix proportion. The FAC-10 pavement layer was tracked and tested using a pavement texture tester to study the change in its skid resistance under traffic load from a macroscopic and microscopic perspective. The influence of traffic load on the deformation of the FAC-10 wearing layer was also simulated and analyzed via lab tests. The results show that the new FAC-10 epoxy asphalt mixture is superior to the traditional EA-10 epoxy asphalt mixture in terms of skid resistance. During the monitoring and testing period, the three-dimensional (3D) structure depth of the pavement surface showed a decreasing trend followed by an increasing trend, while the density of microtexture distribution showed the opposite trend. After a wheel pressure rutting test, the rutted slab showed slight deformation and a certain degree of reduction in 3D structure depth; the deformation of the rutted slab mainly occured in the surface layer, and the internal deformation was negligible. Full article

To comprehensively investigate the integrated structural and material design of the epoxy asphalt mixture used in steel bridge deck pavement, the following works have been conducted: 1. The strain level of steel bridge deck pavement was calculated; 2. The ultimate strain level of fatigue endurance for epoxy asphalt concrete was measured; 3. The effect of water tightness of epoxy asphalt mixture on the bonding performance of steel plate interface was tested. 4. For better performance evaluation, quantitative analysis of the anti-skid performance of epoxy asphalt mixture was carried out by testing the structure depth using a laser texture tester. Results show the following findings: 1. The fatigue endurance limit strain level of epoxy asphalt mixture (600 με) was higher than that of the steel bridge deck pavement (<300 με), indicating that the use of epoxy asphalt concrete has better flexibility and can achieve a longer service life in theory; 2. The epoxy asphalt concrete has significant water tightness to protect the steel plate interface from corrosion and ensure good bonding performance; 3. The porosity of epoxy asphalt mixture used in steel bridge deck paving should be controlled within 3%; 4. In terms of anti-skid performance of bridge deck pavement, the FAC-10 graded epoxy asphalt mixture is recommended when compared with EA-10C. Full article

This study aims to evaluate the economy of a steel bridge deck pavement scheme (SBDPS) using a comprehensive life-cycle cost (LCC) analysis approach. The SBDPS are divided into the “epoxy asphalt concrete system” (EA system) and “Gussasphalt concrete system” (GA system) according to the difference in the material in the lower layer of the SBDPS. A targeted LCC checklist, including manager cost and user cost was proposed, and a Markov-based approach was applied to establish a life-cycle performance model with clear probability characteristics for SBDPS. Representative traffic conditions were designed using a uniform design method, and the LCC of SBDPS under representative traffic conditions and different credibility (construction quality as a random factor) was compared. The reliability of the LCC analysis approach was verified based on the uncertainty analysis method. Based on an expert-scoring approach, a user cost weight was obtained to ensure it is considered reasonably in the LCC analysis. Compared with the cumulative traffic volume, the cumulative equivalent single axle loads (CESAL) have a closer relationship with the LCC. The GA system has better LCC when the CESAL is less, while the EA system is just the opposite. The breaking point of CESAL for the LCC of the EA system and the GA system is 15 million times. The LCC analysis of SBDPS should consider the influence of random factors such as construction quality. The comprehensive LCC analysis approach in this paper can provide suggestions for bridge-management departments to make a reasonable selection on SBDPS. Full article

The type and fineness of a filler significantly affect the performance of an asphalt mixture. There is a lack of specific research on the effects of filler fineness and dust from aggregates on the properties of epoxy asphalt (EA) mixtures. The effects of aggregate dust and mineral powder on the properties of an EA mixture were evaluated. These filler were tested to determine their fineness, specific surface area and mineral composition. The effects of these fillers on the EA mastic sample and mixture were evaluated. The morphology of the EA mastic samples was analyzed using scanning electron microscopy (SEM). The effects of the fillers on the Marshall stability, tensile strength and fatigue performance of the EA mixture were evaluated. The dust from the aggregates exhibited an even particle size distribution, and its average particle size was approximately 20% of that of the mineral powder. The SEM microanalysis showed that the EA mastic sample containing relatively fine dust formed a tight and dense interfacial bonding structure with the aggregate. The EA mixture sample containing filler composed of dust from aggregate had a significantly higher strength and longer fatigue life than that of the EA sample containing filler composed of mineral powder. Full article

Epoxy asphalt (EA) concrete is widely used in constructing long-span steel bridge pavements (SBDPs). This study aims to derive a fatigue damage evolution law, conducting an experimental investigation of SBDP. First, a general theoretical form of the fatigue damage evolution law of materials is established based on the thermal motion of atoms. Then, fatigue experiments demonstrate that this evolution law well represents the known damage–life relationships of SBDP. Taking into account the experimental relationships between damage and fatigue life under symmetrical cyclic loadings with different overload amplitudes and temperature variations, a detailed damage evolution law is deduced. Finally, the role of damage accumulation is discussed on the basis of the proposed damage evolution law for the extreme situation of heavy overload and severe environments. The results show that both heavy loading and falling temperatures increase the fatigue damage of SBDP considerably. EA shows a fatigue life two to three times longer than that of modified matrix asphalt (SMA) or guss asphalt (GA). For the same thickness, EA pavement is demonstrated to be more suitable for an anti-fatigue design of large-span SBDP under high traffic flows and low temperatures. Full article