Search Results (7)

Efficient and accurate recognition of highway pavement cracks is crucial for the timely maintenance and long-term use of expressways. Among the existing crack acquisition methods, human-based approaches are inefficient, whereas carrier-based automated methods are expensive. Additionally, both methods present challenges related to traffic obstruction and safety risks. To address these challenges, we propose a fixed pan-tilt-zoom (PTZ) vision-based highway pavement crack recognition workflow. Pavement cracks often exhibit complex textures with blurred boundaries, low contrast, and discontinuous pixels, leading to missed and false detection. To mitigate these issues, we introduce an algorithm named contrast-enhanced feature reconstruction (CEFR), which consists of three parts: comparison-based pixel transformation, nonlinear stretching, and generating a saliency map. CEFR is an image pre-processing algorithm that enhances crack edges and establishes uniform inner-crack characteristics, thereby increasing the contrast between cracks and the background. Extensive experiments demonstrate that CEFR improves recognition performance, yielding increases of 3.1% in F1-score, 2.6% in mAP@0.5, and 4.6% in mAP@0.5:0.95, compared with the dataset without CEFR. The effectiveness and generalisability of CEFR are validated across multiple models, datasets, and tasks, confirming its applicability for highway maintenance engineering. Full article

In China, a substantial portion of highway asphalt pavements are no longer capable of accommodating increasing traffic volumes and necessitate renovation and expansion. Prior to commencing such activities, it is crucial to evaluate the performance of the existing asphalt pavements. This study developed a novel normal cloud framework integrating a comprehensive weighted indicator system for existing asphalt pavement. Five key performance indicators including riding quality index (RQI), rutting area ratio (R_r), cracking area ratio (C_r), patching area ratio (P_r), and pavement structural strength index (PSSI) were selected to holistically represent the pavement condition in highway renovation and expansion projects. Subsequently, a method was proposed to determine the weights of these indicators by integrating the analytic hierarchy process (AHP) and entropy. A normal cloud model was constructed to address data characteristics and representation of indicator fuzziness/randomness through digital cloud modeling. The model was applied to 12 sections of the Jingjintang Expressway (Tianjin section). The results revealed only one section where the normal cloud model differed from the pavement maintenance quality assessment (PQI) model. The 3D ground-penetrating radar detection results of this different section indicated that the normal cloud model more closely aligned with the road structure condition. Compared to absolute pass/fail criteria of the traditional PQI model, the cloud model offered enhanced sensitivity to define graded condition assessments essential for reconstruction planning and decision analysis. Therefore, the normal cloud model is more suitable for assessing the performance of existing asphalt pavements in highway reconstruction and extension projects compared to the PQI model. Full article

Due to the increasing development of highway reconstruction and expansion projects in China, many large-span highway tunnels are being constructed near existing highway tunnels. Tunneling underneath will inevitably cause variation in the surrounding rock displacement and may even lead to collapse. In this study, based on an analysis of extensive field monitoring data from the Gucheng tunnel, the variation law for the surrounding rock full-displacement and the influence of the tunnel-face spatial effect in a large-span mudstone tunnel are analyzed. The change in the full displacement experienced the following sequence: slow pre-displacement growth → rapid increase → slow increase → gradual stability. The displacement released by the excavation of the tunnel construction accounts for 40~60% of the total displacement, and the closer to the excavation contour, the more obvious the displacement release. The final convergence value of vertical displacement is obtained by hyperbolic function regression prediction analysis. Based on this value, Lee and Hoek equations are used for parameter analysis and field-data fitting. It is concluded that the larger the proportion of the early displacement of the surrounding rock before construction to the total displacement, the smaller the influence of the tunnel-face spatial effect on the surrounding rock. The numerical simulation results are compared with actual monitoring results, and good agreement is observed. The larger the burial depth of the tunnel, the smaller the influence range in the tunnel-face spatial effect, and the more concentrated the displacement release. The variation law and the influential range for the surrounding rock full-displacement described in this paper can provide a reference for predicting and controlling the deformation during the construction of future large-span mudstone tunnels. Full article

Considering the development of urban transportation systems and the importance of highway bridges in a city’s resilience against earthquakes, it is critical to pay special attention to the seismic risk evaluation of highway bridges. The most significant issue to consider is the assessment of possible direct and indirect damages imposed on bridges before an earthquake. After this, the best practices for bridge rehabilitation can be adopted to minimize the induced damage. In this paper, we assessed the seismic risks associated with all 713 highway bridges in Tehran province (the capital of Iran). These bridges were initially divided into six categories according to their structural system and construction year and were also classified by whether or not seismic design was included. Among the 84,000 earthquakes recommended by the researchers’ ten-thousand-year catalog, a set of 50 ground motion records was selected in the course of a probabilistic approach via the Optimization-based Probabilistic Scenarios (OPS) algorithm in an attempt to obtain the least amount of error compared to the original catalog in the final hazard curve in different regions of Tehran province. Afterward, the seismic fragility curves were plotted in four damage states of slight, moderate, extensive, and complete for the six bridge structural systems of simple, steel, concrete slab box, concrete slab–steel box, concrete slab, and steel girder–concrete slab. The results of the fragility curves extracted from the decision tree analysis were validated with those developed from incremental dynamic analysis (IDA) for a bridge case study modeled in the OpenSEES software V2.5.0. Later, using logical relationships, seismic risk curves were drawn for each structural system. The results show that, in general, the average seismic damage of bridges over ten years old is 0.88 times the average damage of bridges less than ten years old. The highest level of vulnerability is associated with the simple bridge system with a median vulnerability of 0.44. Moreover, the lowest level of vulnerability is related to the steel girder–concrete slab bridge system with a median vulnerability of 0.98, showing an increase of approximately 2.2 times in the median vulnerability. In addition, based on the sensitivity analysis results, the indirect and total risk levels increase almost exponentially with increasing the reconstruction index. Full article

Styrene–butadiene–styrene (SBS) polymer is extensively employed for asphalt pavement construction, and its degradation significantly damages the durability of asphalt concrete. However, the effect of aging protocols on the degradation of SBS polymer in asphalt binder has not been thoroughly investigated. In this study, confocal laser scanning microscopy (CLSM) was applied to characterize the change in morphology with SBS polymer degradation. Various aging protocols were considered, including accelerated aging processes in laboratory- and field-aged samples from three highway sections with different in-service periods. Scanned images of the polymer phase in the 2D plane at different depths were processed and further reconstructed in three dimensions. Furthermore, the three-dimensional polymer morphology indices derived from the semi-quantitative analysis of the images were correlated with the rheological indices. The results show that the polymer particles change from a relatively large ellipsoidal shape to a relatively small spherical shape as aging proceeds. The increase in aging temperature appears to accelerate the degradation of the polymer at the same rheological level. The effect of the laboratory aging method on the polymer was more pronounced during the early stages of aging compared to that in the field aging process. Full article

The concept of the “no-waste city” has focused increasing attention on the recycling of solid waste. One such waste is reclaimed asphalt pavement (RAP), which is generated during road maintenance. The potential to reuse this resource has attracted extensive attention in recent years. This paper explores this concept via a case study of the reconstruction of two sections of the Beijing-Taipei Expressway (from Bengbu to Hefei, sections K69–K69 + 500 and K69 + 500–K69 + 900). The upper base layer of one section was paved with a novel mixture of emulsified asphalt, mixed with a high proportion of RAP made using plant-mixed cold recycling technology (EAPM-HP_RAP). For comparison, the upper base layer of the other section was paved with a conventional large-stone porous asphalt mix (LSPM). The proportions of the components of EAPM-HP_RAP were optimized via laboratory-based proportioning design followed by proportioning verification. The results showed that the high-temperature stability, water damage resistance and pavement strength of the EAPM-HP_RAP met the specifications of relevant engineering standards. Next, the economic and environmental benefits of this novel approach were estimated. The approach was estimated to save CNY (China Yuan) 1.5–1.8 million in engineering costs per km of road (roadbed width = 27.5 m) and CNY 158–189 million for the whole project (105 km in length). It was also estimated to reduce energy consumption equivalent to 67.41 tons of standard coal per km. Further calculations showed that every km of pavement could reduce CO₂ emissions by 176.6 tons, SO₂ emissions by 0.6 tons, NO_X emissions by 0.5 tons, ash emissions by 17.6 tons and soot emissions by 1.0 tons compared with conventional methods. For the whole road section, this is equivalent to reducing CO₂ emissions by 18,543 tons, SO₂ emissions by 60.2 tons, NO_X emissions by 52.5 tons, ash emissions by 1848 tons, and soot emissions by nearly 105 tons. In summary, it is feasible for EAPM-HP_RAP to be used as the upper base layer in highway renovation projects. It reduces the need to mine new ores and allocate land to RAP storage, which is associated with soil and water pollution due to chemical leaching from aged asphalt. This approach provides great economic and environmental benefits compared with the use of conventional pavement technology. Full article

This paper presents a systematic pioneering study on the use of agricultural-purpose frequency domain reflectometry (FDR) sensors to monitor temperature and moisture of a subgrade in highway extension and reconstruction engineering. The principle of agricultural-purpose FDR sensors and the process for embedding this kind of sensors for subgrade engineering purposes are introduced. Based on field measured weather data, a numerical analysis model for temperature and moisture content in the subgrade’s soil is built. Comparisons of the temperature and moisture data obtained from numerical simulation and FDR-based measurements are conducted. The results show that: (1) the embedding method and process, data acquisition, and remote transmission presented are reasonable; (2) the temperature and moisture changes are coordinated with the atmospheric environment and they are also in close agreement with numerical calculations; (3) the change laws of both are consistent at positions where the subgrade is compacted uniformly. These results suggest that the data measured by the agricultural-purpose FDR sensors are reliable. The findings of this paper enable a new and effective real-time monitoring method for a subgrade’s temperature and moisture changes, and thus broaden the application of agricultural-purpose FDR sensors. Full article