Search Results (418)

Multimodal 3D object detection benefits from the complementary nature of camera images and LiDAR point clouds. However, existing voxel–pixel fusion methods typically rely on relatively coarse cross-modal interactions, which limit fine-grained structural modeling and degrade performance on small safety-critical objects. To address this issue, we propose ETA-SDQF, an edge-texture-aware semantic dual-query fusion framework designed to enhance 3D perception of vehicles, cyclists, and pedestrians. The proposed method first introduces an edge-texture-aware image backbone (ETAIB) based on the discrete wavelet transform (DWT), which improves the representation of multi-scale fine-grained image features. Then, we design a dual-query-guided attention fusion (DQGAF) module, which leverages deformable attention to adaptively aggregate voxel-aligned multi-scale image features under joint semantic and edge-texture guidance. Finally, we adopt a hybrid 3D feature learning strategy inspired by PV-RCNN, combining voxel-based feature learning with PointNet-style feature abstraction for processing fused features. This design improves the utilization of voxel features enriched with image semantics, thereby facilitating more reliable 3D object proposal generation. Experimental results on the KITTI dataset demonstrate that the proposed framework achieves better performance compared to existing baseline methods. It consistently improves pedestrian and cyclist detection, while maintaining competitive performance on car detection across different difficulty levels, showing potential benefits on challenging KITTI samples. Full article

With the advancement of marine engineering, coral concrete—comprising coral coarse aggregate, coral sand, and seawater—has garnered increasing research interest. To further investigate its compressive mechanical behavior under axial and lateral biaxial stress states, a total of 9 prismatic specimens under axial loading and 45 cubic specimens under biaxial loading were prepared, encompassing three strength grades (C20, C30, and C40) and five lateral stress ratios (0, 0.25, 0.5, 0.75, and 0.9). The failure modes and corresponding axial and biaxial stress–strain curves were meticulously recorded. The axial mechanical response was systematically analyzed, leading to the establishment of a compressive damage constitutive model based on the Weibull distribution. Additionally, the influence of the lateral stress ratio on both peak stress and peak strain was examined, and multiple biaxial failure criteria were formulated. Experimental results reveal that the failure modes of coral concrete specimens are analogous to those of natural coarse aggregate concrete and are significantly affected by the lateral stress ratio. Specifically, an increase in the lateral stress ratio results in higher peak stress, while the absolute value of peak strain exhibits a linear variation. Finally, the proposed axial damage constitutive model and the biaxial failure criteria are rigorously validated against the experimental data. Full article

The accumulation of waste tyres presents a significant environmental challenge owing to their non-biodegradable nature and limited recycling options. The incorporation of tyre-derived rubber into concrete offers a promising strategy to reduce landfill waste and lower the consumption of natural aggregates. This study presents an integrated experimental and machine learning-based framework for evaluating and predicting the performance of rubberized concrete. M25-grade concrete mixtures were prepared with partial replacement of coarse aggregates by waste tyre rubber at proportions of 0%, 10%, 20%, and 30% by volume. Mechanical performance was assessed through compressive and split-tensile strength tests, whereas durability was evaluated using water absorption measurements. Microstructural characterization was conducted using scanning electron microscopy and X-ray diffraction analysis. In parallel, predictive models based on artificial neural networks, adaptive neuro-fuzzy inference systems, and fuzzy logic were developed and validated using statistical measures. The results showed that increasing rubber content reduced mechanical strength and increased water absorption due to weaker interfacial bonding and higher porosity. Nevertheless, concrete containing a 10% rubber replacement retained approximately 90% of the control strength while maintaining satisfactory durability. The machine learning models demonstrated strong predictive accuracy for estimating concrete properties. Overall, the findings suggest that limited incorporation of waste tyre rubber can contribute to the development of sustainable and low-carbon concrete materials with reduced embodied energy and environmental impact. Full article

This study evaluates the feasibility of utilizing wood ash (WA), derived from grilled-fish barbecue waste, as a supplementary cementitious material, in combination with crushed clay blocks (CCB) as partial or full replacements for natural coarse aggregate, to improve the sustainability of concrete. A total of twelve concrete mixtures were produced using WA replacement levels of 0%, 10%, 20%, and 30% and CCB replacement levels of 0%, 50%, and 100%. The concrete specimens were evaluated in terms of workability, compressive strength, splitting tensile strength, flexural strength, density, water absorption, ultrasonic pulse velocity (UPV), thermal conductivity, and microstructural characteristics using scanning electron microscopy (SEM). The results show that replacing cement with 10% WA achieved the highest mechanical performance at 56 days, with compressive, splitting tensile, and flexural strengths of 50.58 MPa, 5.54 MPa, and 6.07 MPa, respectively. These results represent an improvement of 11% in concrete properties compared with the control mixture. However, the use of 20% of WA enhanced microstructural densification through pozzolanic reactions, whereas higher replacement levels resulted in increased porosity, the presence of unreacted particles, and reductions in strength and UPV values. In contrast, increasing the WA and CCB contents reduced density and workability while significantly increasing water absorption. Among the investigated mixtures, the combination of 10% WA and 50% CCB provided the most favorable balance between mechanical performance, thermal efficiency, and sustainability. Further studies are recommended to evaluate the long-term durability and economic feasibility of the proposed replacement levels for sustainable concrete production. Full article

This study investigates the feasibility of recycling scallop shells as a partial substitute for natural coarse aggregates in concrete at replacement rates of 20%, 30%, and 40% by mass. The originality of the work lies in combining conventional mechanical and durability tests with a six-month environmental monitoring protocol under simulated rainfall and an end-of-life regulatory interpretation of chemical release. Processed shells were used as a 2/20 mm coarse fraction and characterized by a density of 2713 kg/m³, a water absorption of 2.93%, and a Los Angeles coefficient of 15.1. At 28 days, compressive strength decreased from 33.7 MPa for the reference concrete to 27.9 MPa, 28.1 MPa, and 26.7 MPa for SS20, SS30, and SS40, respectively. Water-accessible porosity increased from 7.8% to 9.9%, and carbonation depth after 70 days increased from 6.2 mm to 12.8 mm at 40% shell replacement. In contrast, chloride ion migration decreased from 19.0 × 10⁻¹² m²/s for the reference concrete to 17.4, 16.3, and 12.1 × 10⁻¹² m²/s at 90 days for SS20, SS30, and SS40, respectively. Environmental monitoring showed low runoff concentrations for anions and trace metals, all below the French regulatory thresholds considered in this work. Under the conditions of this study, shell replacement up to 30% appears technically feasible for non-structural or lightly loaded applications, while the environmental behavior remained compatible with an inert end-of-life classification. Full article

Myocardial scar and edema segmentation from multi-sequence cardiac magnetic resonance (MS-CMR) is important for myocardial infarction assessment, but remains challenging due to heterogeneous modal characteristics, severe class imbalance, and the small, ambiguous nature of pathological regions. To address these issues, a dynamic synergistic segmentation network (DSS-Net) is proposed for myocardial pathology segmentation. The framework adopts a coarse-to-fine strategy, in which a coarse stage first segments the myocardium to provide anatomical priors and region constraints, and a fine stage then delineates scar and edema within the myocardium-aware space. In addition, a Modality Dynamic Fusion Module (MDFM) is designed to adaptively emphasize pathology-relevant modal information, and a Stage Feature Aggregation Module (SFAM) is introduced to enhance cross-stage feature interactions and fine-grained lesion representation. Experiments on the MyoPS 2020 and MyoPS 2024 datasets demonstrate that DSS-Net achieves competitive and balanced performance, reaching Dice scores of 0.706 for scar and 0.753 for edema on MyoPS 2020. Additionally, compared with SOTA methods in the MyoPS 2020 Challenge, the proposed method attains comparable scar segmentation performance while maintaining a more balanced trade-off between sensitivity and specificity. These findings suggest that combining anatomical guidance with pathology-aware multi-modal learning is a promising strategy for robust myocardial pathology segmentation in MS-CMR images. Full article

This study investigates the valorization of construction and demolition (C&D) waste streams and an industrial by-product for sustainable concrete production. Recycled concrete aggregates (RCA) and recycled brick aggregates (RBA), derived from C&D wastes, together with pelletized recycled fly ash aggregates (FAA) produced from thermal power plant fly ash, were used as total replacements for natural coarse aggregates. Six concrete mixtures were prepared at a constant water-to-cement ratio of 0.50 using untreated and slag slurry–treated aggregates. A slag slurry-based two-stage mixing approach (TSMA), incorporating ground granulated blast furnace slag (GGBFS), was applied as a practical and potentially scalable treatment method to enhance aggregate quality and interfacial bonding. The results show that complete replacement of natural aggregates reduced fresh concrete unit weight by up to 17%, while meeting the minimum compressive strength requirements for structural applications. Slag slurry treatment led to statistically significant improvements in mechanical properties, reduced variability, and enhanced overall reliability. In addition, widely used code-based prediction models (TS500, ACI, Eurocode-2, NZS 3101-1:2006, and CSA A23.3-04), originally developed for conventional concrete, were evaluated for their applicability in estimating key mechanical properties of recycled and by-product aggregate concretes, and alternative regression-based models were developed to improve prediction accuracy. Overall, the findings demonstrate the potential for effective utilization of C&D wastes and industrial by-products in structural concrete, contributing to resource efficiency and reduced reliance on natural aggregates. Full article

Existing research on the axial compressive performance and size effect of carbon fiber-reinforced polymer (CFRP)-confined recycled aggregate concrete (RAC) short columns mainly relies on macroscopic experimental analysis, lacking research methods capable of reflecting the heterogeneous characteristics of materials and mesoscopic damage evolution mechanisms. Accordingly, a three-dimensional mesoscale finite element method was adopted in this study to establish a five-phase RAC mesoscopic model, including natural aggregates, old mortar, old interfacial transition zones (ITZs), new mortar, and new interfacial transition zones. Different from existing studies, predominantly based on macroscopic experiments or empirical models, this paper focuses on revealing the coupled effects of the recycled aggregate replacement ratio, the number of CFRP confinement layers, and specimen size. A total of 48 specimens were designed, covering four specimen sizes, four recycled coarse aggregate replacement ratios, and three CFRP confinement layers. The effects of these parameters on failure modes, stress–strain relationships, and size effect were systematically analyzed. The results indicate that the peak stress decreases significantly with the increase in the recycled coarse aggregate replacement ratio; the increase in CFRP layers markedly improves both the bearing capacity and post-peak bearing capacity retention rate; the ultimate stress generally declines as the specimen size increases, which highlights the pronounced size effect of CFRP-confined RAC short columns. Based on peak parameters and normalization analysis, a simplified stress–strain model was established: the goodness of fit R² of the ascending branch is 0.98565, and the goodness of fit for the descending branch parameters are ${\mathrm{R}}_{\mathsf{\beta }}^2$= 0.9655 and ${\mathrm{R}}_{\mathsf{\gamma }}^2$= 0.9350. Compared with existing models, the proposed model achieves a low prediction error of only 1.5–6.9%, demonstrating superior prediction accuracy. It can accurately describe the complete compressive process of CFRP-confined RAC short columns and provide a mesoscopic mechanistic basis for engineering design. Full article

With the advancement of China’s carbon peaking and carbon neutrality targets and the low-carbon upgrading of the construction industry, steel fiber recycled aggregate concrete (SFRAC) has attracted increasing attention as a sustainable construction material due to its advantages in resource recycling and enhanced mechanical performance. However, its compressive strength is influenced by multiple interacting factors, making accurate prediction challenging when using conventional empirical or regression-based methods. To enhance predictive performance, a compressive strength database was established based on published experimental data. The input layer included seven mixture parameters: water content, cement content, fine aggregate content, natural coarse aggregate content, recycled coarse aggregate content, steel fiber content, and superplasticizer dosage, with the 28-day compressive strength serving as the output variable. Using this database, four prediction models were developed, including a back-propagation (BP) neural network and three optimized variants—GA–BP, PSO–BP, and GA–PSO–BP, optimized by genetic algorithm (GA) and particle swarm optimization (PSO)—were developed. Their performance was evaluated using the coefficient of determination (R²), root mean square error (RMSE), and mean absolute error (MAE). Among the four models, GA–PSO–BP produced the best predictive performance, with a best-run R² of 0.9308 on the validation set, exceeding the BP, GA–BP, and PSO–BP neural networks by 0.0642, 0.0326, and 0.0512, respectively. Over 10 independent runs, it attained an average R² of 0.8822 and consistently delivered the lowest RMSE and MAE with small standard deviations, confirming its superior predictive accuracy and stability. These findings suggest that integrating GA and PSO can effectively enhance the predictive accuracy and stability of the BP neural network, thereby providing a dependable reference for compressive strength prediction and mix proportion optimization of steel fiber recycled aggregate concrete. Full article

The increasing generation of ceramic waste from manufacturing defects, construction activities, and demolition operations poses significant environmental and waste management challenges worldwide. This study presents a preliminary investigation into the incorporation of ceramic waste aggregates (CW) as partial and full replacement for natural coarse aggregates in fly ash-based geopolymer concrete (GPC) under water-curing conditions. Five mix compositions were prepared with ceramic waste aggregate replacement levels of 0%, 20%, 40%, 60%, and 100%. Fresh and hardened properties were evaluated using flow table and early-age compressive strength tests at 7 and 14 days. The 20% replacement mix achieved the best compressive strength value of 5.52 MPa at 14 days, slightly exceeding the control GPC mix (5.09 MPa) among the limited mixtures investigated in this preliminary study. However, higher replacement levels resulted in reduced compressive strength, which may be associated with increased porosity, weaker aggregate–matrix bonding, and limitations related to the adopted water-curing regime. Workability remained within acceptable flow ranges for most mixes, although reduced flowability was observed for the 40% replacement. The comparatively low strength values obtained across all mixtures may largely be associated with the absence of heat curing and the inclusion of additional water to improve workability, both of which likely limited the geopolymerization efficiency. Based on the comparatively low compressive strength values obtained, the investigated mixtures, in their current form, are only suitable for low-strength or non-structural applications rather than structural concrete applications. Overall, this study provides preliminary insights into the influence of ceramic waste coarse aggregates on the workability and early-age compressive strength behavior of fly ash-based geopolymer concrete under the adopted experimental conditions. Further optimization of the curing regimes, mix design parameters, and long-term mechanical and durability performance is necessary before broader engineering applicability can be established. Full article

This study investigates the effect of mass-based replacement of natural coarse aggregate with electric arc furnace (EAF) slag on the performance of ordinary Portland cement (OPC) concrete. Replacement levels of 0%, 30%, 50%, and 100% were examined, with particular attention to the volumetric changes induced by the higher density of EAF slag, which leads to an increase in paste volume. Fresh, mechanical, durability-related, and microstructural properties were evaluated. Results show a continuous reduction in workability with increasing slag content, despite the increase in paste volume, indicating the dominant influence of aggregate morphology on rheological behavior. Mechanical performance exhibited a non-linear response. Within the tested series, the 50% replacement mixture showed the highest mean compressive and splitting tensile strengths; however, the compressive strength difference relative to the control mixture remained small and within typical experimental scatter. In contrast, water absorption decreased progressively, reflecting improved matrix densification. However, this densification did not translate into enhanced mechanical performance, highlighting a decoupling between durability-related indicators and strength. A screening-level CO₂ assessment further showed that reductions in aggregate-related emissions were offset by increased cement content associated with mass-based replacement. The results emphasize the importance of considering volumetric effects when interpreting the behavior and sustainability of slag-based concrete. Note: all strength comparisons are based on mean values from three-specimen sets without formal statistical testing and should be regarded as exploratory observations. Full article

Coal gangue, a by-product of coal mining, has attracted increasing attention as an alternative aggregate in concrete because it can reduce natural aggregate consumption and promote solid-waste utilization. However, its porous, heterogeneous, and source-dependent nature often leads to weak interfacial bonding, reduced strength, and poor durability. Fiber reinforcement has been widely investigated as an effective strategy to compensate for these deficiencies, but the reported results remain scattered because of differences in gangue source, replacement level, fiber type and dosage, and test methods. This review systematically synthesizes the effects of fiber reinforcement on the mechanical performance, durability, and sustainability of coal gangue concrete. Reported results are comparatively analyzed as functions of coal gangue replacement level and fiber dosage. Two strength-normalized sustainability indicators, namely the Cost Coefficient Index (CCI) and Carbon Emission Index (CEI), are further introduced to compare the economic and environmental efficiency of different mixtures. Relatively favorable overall performance was most frequently reported within the commonly reported coal gangue replacement range for coarse aggregates, about 35–70%, with steel fiber and basalt fiber commonly showing favorable intervals of about 0.8–1.0% and 0.12–0.15%, respectively; polypropylene fiber also appeared favorable at about 0.6–1.0%, although the supporting evidence is comparatively less extensive. Full article

Recycled aggregates (RAs) from construction and demolition waste (CDW) provide substantial circular-economy benefits, yet their elevated porosity, adhered mortar, and heterogeneity typically impair the mechanical performance and durability of recycled aggregate concrete (RAC). This PRISMA 2020-compliant systematic review synthesises 2180 records (2015–2026) to evaluate advanced strategies for enhancing RA quality prior to structural use. This paper critically compares removal-based treatments (mechanical, thermal, acid cleaning) with strengthening and densification approaches, including accelerated carbonation, pozzolanic and nano-silica coatings, polymer impregnation, microbial-induced calcium carbonate precipitation (MICP), and modified mixing methods such as triple-stage mixing (TSMA). Evidence shows that while all RA types (including recycled fine aggregate (RFA), recycled coarse aggregate (RCA), and their combination (RFCA)) can slightly reduce compressive strength and 30% replacement serves as a critical threshold, beyond this, strength loss accelerates, particularly in RCA and RFCA mixes. However, accelerated carbonation and TSMA consistently refine the interfacial transition zone, reduce water absorption by 17–30%, and recover 85–94% of natural aggregate concrete strength. Bio-deposition reduces water absorption by 13–21%, while acid/silica fume treatments improve late-age strength but carry environmental trade-offs. This review formulates a practice-oriented implementation framework for structural-grade RAC. Sustainability analyses indicate that carbonated RA can achieve net-positive CO₂ abatement when under low-carbon energy supply. A mechanistic schematic is presented to synthesise treatment-to-pore-structure/durability pathways across the four principal treatment routes, and a quantitative synthesis plot compares water absorption reductions across all treatment types using 13 data points drawn from included studies. A structured treatment comparison evaluates the energy intensity, industrial scalability, CO₂ footprint, and technology readiness level for each strategy. The remaining challenges include a lack of hybrid treatment studies, limited real-scale durability data, and insufficient mechanistic models linking treatment to pore structure evolution. This review recommends harmonised durability-based criteria and updates to standards (e.g., BS 8500, EN 12620) to support the scalable deployment of treated RA. Full article

Against the background of the global “dual carbon” strategic goal, low-carbon upgrading of road engineering and efficient recycling of waste plastics have become critical approaches to relieve the shortage of natural aggregates and control plastic pollution. Most existing studies only focus on the optimization of single mechanical indicators, while lacking collaborative analysis of mechanical performances and carbon reduction benefits, meaning they cannot provide sufficient scientific support for the design of low-carbon and sustainable road materials. In this study, recycled plastic aggregate (PA) was used to partially replace natural coarse aggregate, and its influence on the mechanical characteristics of cement-stabilized macadam (CSM) was systematically investigated. Combined with life cycle assessment (LCA), the carbon emission reduction potential was quantitatively evaluated, aiming to improve the toughness of road base materials and promote low-carbon sustainable development. The results demonstrate that when the PA content increases from 0% to 20%, the mechanical strength of CSM gradually decreases, while the toughness presents a steady upward trend, and the maximum carbon emission reduction rate reaches 50.8%. The optimal toughness improvement of 28.39% is obtained at the PA content of 16%. This study clarifies the internal correlation between mechanical behaviors and low-carbon benefits of recycled plastic aggregate, provides reliable technical support for the high-value utilization of waste plastics and the optimization of sustainable road materials, and offers important references for the green and low-carbon transformation of transportation infrastructure. Full article

The urgent global need for sustainable infrastructure drives the demand for high-value buildings and waste removal. This paper studies the feasibility of using recycled foam concrete aggregate (FCA) as a substitute for natural coarse aggregate (NCA) in concrete and studies its impact on rheology, mechanical degradation, shear resistance, and the full-range replacement ratio (0–100). The experimental results show that the monotonic change in the workability of fresh concrete determines the lubrication threshold at 60% replacement, which is driven by the volume proportion effect. Beyond this value, capillary suction dominates, and the viscosity rises rapidly. From a mechanical perspective, the porous structure of FCA is conducive to “internal curing” so that moisture is released from the drying interface, but it also becomes a source of defects that change the fault topology. Specifically, the critical transition of the shear failure mode shifts from the debonding of the interface to the crushing of the cross-particle aggregate. At this time, the shear capacity decreases substantially, experiencing a reduction of 71.8% when completely replaced. There is a strong correlation between ultrasonic pulse velocity (UPV), rebound number, and compressive strength, and a multivariate nonlinear regression model (R² > 0.85) with non-destructive strength prediction is ultimately obtained. Based on the balance between mechanical capacity and resource cyclability, an optimal alternative zone of 20% to 40% is proposed. This work not only provides a mechanism for multi-scale coupling between pore structure and structural properties but also provides a data-driven method for the safety assessment of lightweight recycled aggregate concrete (RAC). Full article