Asphalt pavements are commonly used for highways and airport runways. In pavement design and analysis, environmental factors such as temperature need to be taken into account to accurately predict the service life of asphalt pavements. The effect of temperature variations on the mechanical performance of asphalt mixtures was investigated at the microscale in this study. X-ray computed tomography (X-ray CT) scanning and digital image processing (DIP) techniques were applied to detect, analyze, and reconstruct the microstructure of asphalt specimens. Based on DIP, indicators related to air voids before and after fatigue testing were obtained and are discussed in this study. The results show that higher test temperatures resulted in larger air voids and promote crack initiation. Asphalt specimens measured at higher temperatures exhibited more prominent cracking characteristics because of decreased bonding capability between asphalt mastic and aggregates and because of decreased strength of the asphalt mastic. Finite-element simulations were conducted to simulate uniaxial compression tests. With increasing temperature, the proportion of larger compressive maximum principal stresses at the interface between the asphalt mortar and the aggregates decreased. Energy dissipation decreased with increasing temperature. The results reveal the significant influence of temperature on the fatigue damage and mechanical responses of asphalt; further investigations should be carried out to facilitate the improvement of the pavement design process.

Modular construction methods are adopted in many spatial and temporal limited projects. As the major equipment used in modular construction, the mobile crane affects the safety and efficiency of construction significantly. Currently, building information modeling (BIM) is widely adopted to improve the lifting operation planning of cranes. However, the inaccurate simulation of the dynamic construction environment makes those BIM‐based lifting operation planning methods unsuitable for land mobile cranes operation planning, such as in the overpass bridge construction project, which may cause several safety risks during the lifting process. Based on an overpass steel bridge construction project, this paper attempted to integrate the BIM and unmanned aerial vehicles (UAVs) to streamline lifting operation planning and construction monitoring. Specifically, in the preliminary stage, a level of development (LOD) 400 steel superstructure model was built and then divided into eighty sections. In addition, a three‐dimensional (3D) geology model of the as‐is construction site was modeled by UAV‐captured images. Then, a fusion model which contains the lifting modules models, the as‐is site model, and the crane model was gathered, based on which the collision detection was conducted by 4D crane operating path simulation. According to the results, three potential collisions were found and eliminated by lengthening the jib of the crane from 43.5 m to 46.5 m. Furthermore, the optimum crane location for lifting each steel structure was determined based on the 3D geology model. The study shows that the UAV is able to acquire geological information and then 3D simulates the real construction environment quickly and accurately. Furthermore, BIM and UAV have the potential to optimize the design and construction as well as the monitoring of bridge projects.

Construction and demolition waste material is of great potential for use in pavement engineering. This paper aims to investigate the feasibility of ceramic waste aggregate (CA) used in cooling asphalt pavement through a series of test methods and simulation techniques. Stone mastic asphalt (SMA) containing 10%, 20%, 30%, 40%, and 50% coarse ceramic waste aggregate (CASMAs) was first designed using the Marshall method. Afterward, the road performance and thermal insulation performance of the five different CASMAs were assessed by a comprehensive lab test, including a wheel rutting test, moisture susceptibility test, bending beam test, fatigue beam test, and indoor thermal insulation test. Finally, a 2D finite-element (FE) model was developed to investigate the transient thermal field and rutting deformation response of the cooling asphalt pavement with CASMAs. Results show that CASMAs experienced degradation of rutting resistance, moisture susceptibility, and anti-cracking performance while still meeting technical requirements with CA content of up to 40%. On the other hand, CASMAs can cool the pavement’s temperature by 11.5 °C at the bottom of asphalt layers. The permanent rutting deformation of cooling asphalt pavement was 45.36% smaller than that of conventional asphalt pavement without CASMAs. Based on the test results and numerical simulation results, the optimum content of ceramic waste aggregate in stone mastic asphalt was recommended as 40%.

Gussasphalt concrete (GAC) is increasingly used in long-span steel bridge deck pavements because of its impermeability and compliance. However, the paving temperature of GAC is very high, inducing a significant nonuniform temperature distribution in the bridge during paving, and this has an adverse effect on the serviceability of bridge. In this study, the temperature behavior and stability of orthotropic steel bridge deck (OSBD) during the GAC paving were investigated. First, the temperature distribution of a steel bridge during the GAC paving was studied using field monitoring and numerical simulation. Second, the temperature stress and deformation of the OSBD during GAC paving were calculated. Third, the effect of the temperature deformation of OSBD on pavement unevenness was examined. Last, a submodel and eigenbuckling analysis method was used to evaluate the stability of the U ribs during the GAC paving. The results show that uplift and expanded deformation occur in the steel bridge deck during the GAC paving, and this deformation could cause a nonuniform thickness distribution of pavement. The temperature load during paving could reduce the ultimate bearing capacity of the U ribs in the paving area, and there is a hidden danger of instability in the OSBD during the GAC paving.

In order to investigate the fracture performance of lightweight epoxy asphalt concrete (LEAC) used in steel bridge deck pavement, experiments and numerical simulations were used to analyze the effect of lightweight aggregate (LWA) on fracture behavior of LEAC. The gradations of LEAC with different LWA contents were determined by the Marshall method, indirect tensile test with and without freeze-thaw processing were used to measure the indirect tensile strength and moisture stability of LEAC, and fracture properties were evaluated by three-point bending beam test at 15°C and −10°C. Also, internal structures of LEAC were scanned by X-ray CT device to develop three-dimensional finite element models (3D-FEM), and mechanical states of basalt aggregate, LWA, and epoxy asphalt mastic (EAM) were also studied. The results show that the LWA has an obvious influence on fracture properties of LEAC; LWA content 5% can significantly improve the fracture performance. EAM is the main bearing structure of LEAC; mi...

The interfacial zone between aggregate particles and asphalt mortar presents a significant effect on the strength of an asphalt mixture. In this paper, basalt, limestone, and diabase were selected, and the influence of these aggregates on the mechanical characteristics and microstructures of the interfacial zone was investigated. Nanoindentation was employed to measure the change law of mechanical behavior in the region of the interfacial zone, and corresponding viscoelastic parameters were deduced; microstructural morphology was observed by scanning electron microscopy, and the effect of the mineralogical components on the interfacial zone was analyzed as well. Results show that the mechanical behavior of the interfacial transition zone is complicated. The modulus and hardness of asphalt mortar decrease with the increases in the aggregate surface distance, and then keep stable after the distance is greater than 40 μm. Both the relaxation time and dissipated energy ratio of the interfacial zone affected by the different aggregate types show a similar change law. These states indicate that aggregate types have little influence on the stress dissipation of asphalt mortar. However, creep compliances that quantify the ability of the deformation resistance show a significant difference; microstructure morphologies of the interfacial zone are affected by aggregates obviously, and micro pores present a different distribution and state in the interfacial zone.