Acoustic emission (AE) monitoring is widely used for concrete damage identification, but AE descriptors are often interpreted independently from the stress–strain response, which weakens cross-specimen transfer under small-sample destructive testing. To address this issue, this study proposes a curve-conditioned physics-guided learning framework for damage evolution identification in multi-scale fibre-reinforced rubberized concrete under compression. Irregular event-level AE tables are converted into synchronized loading-window sequences, and each window is coupled with curve-derived mechanical variables. A curve-conditioned physics-guided temporal network is further developed with AE tokens, curve tokens, cross-attention fusion, monotonic latent damage evolution, and multi-task supervision. Leave-one-specimen-out experiments show that AE-only models generalize poorly, whereas curve-conditioned learning substantially improves damage-stage recognition. The best tabular curve-conditioned baseline achieves 0.928 accuracy and 0.905 macro-F1, while the full CC-PGT model further improves the results to 0.987 accuracy, 0.977 macro-F1, 0.023 damage RMSE, and 0.017 damage MAE. These results demonstrate that stress–strain curve conditioning provides an effective and mechanically interpretable route for small-sample AE damage assessment.
Given the increasing application of friction stir welding (FSW) in aluminium alloy (AA) structures, the availability of a reliable constitutive model to describe the material response under cyclic loading is essential for robust structural mechanics analysis. In this study, FSW was employed to produce butt joints in 12-mm-thick AA7075-T6 plates. The hardness distribution and microstructure across the butt joints were characterised. Additionally, a systematic investigation was conducted into the monotonic properties, hysteretic stress-strain curves, cyclic backbones, energy dissipation capacities and accumulative evolution laws for both the butt joints and the corresponding base materials (BMs). The Sparrow Search Algorithm was employed to calibrate the material parameters of the Chaboche and Steel4 models, after which a modified Chaboche model was developed and validated. Moreover, three popular accumulative damage models of Shen-Dong, Park-Ang and Kumar-Satish models were calibrated against the experimental data. A comparative analysis was performed, evaluating the hysteretic stress-strain curves, energy evolution and accumulative damage indices of the FSW joints against those of various other structural metals. The results indicated that plasticity-induced accumulative damage in FSW AA7075-T6 butt joints and corresponding BMs was generally more pronounced than that in most structural steels, but less severe than that observed in AA7A04-T6.
The building sector is a major contributor to greenhouse gas emissions, creating an urgent need for practical approaches to support low-carbon building design. Although Building Information Modeling (BIM) and Life Cycle Assessment (LCA) have been increasingly integrated, their application to hospitality buildings in developing countries remains limited. This study proposes a BIM-integrated LCA framework to evaluate and reduce environmental impacts during the design stage. A twelve-story hotel project in Vietnam was selected as a case study. Autodesk Revit and One Click LCA were integrated to assess environmental performance according to the EN 15978 standard. Two scenarios were compared: a conventional reinforced-concrete baseline design and a low-carbon alternative incorporating supplementary cementitious materials, recycled steel, autoclaved aerated concrete blocks, photovoltaic systems, and water-efficiency measures. The results show that the low-carbon scenario reduced global warming potential from 9.19 million kg CO2e to 5.93 million kg CO2e, corresponding to a reduction of 35.4%. Significant reductions were also observed in acidification, eutrophication, ozone depletion, photochemical ozone formation, and fossil-resource depletion. Compared with recent BIM–LCA studies, which typically report carbon reductions of 15–30%, the proposed framework demonstrates the effectiveness of combining multiple low-carbon strategies within a unified design workflow. Material production remained the dominant contributor to life-cycle impacts in both scenarios, highlighting the importance of embodied-carbon mitigation. The proposed framework provides a practical decision-support tool for architects and engineers and can be extended to other building types and regions with different construction practices and environmental databases.
Stacked modular steel structure (SMSS) is experiencing growing global adoption owing to accelerated construction timelines, design flexibility, and component reusability. Corner-supported module units (CMUs) and bolted connections are typical module units and connection types commonly used in typical SMSS. To investigate the seismic behavior of a typical SMSS, a two-story full-scale SMSS was built using the developed CMUs and tri-directional bolted connections (TBCs), and quasi-static tests were conducted to obtain load displacement response, main component strains, failure modes, and connection behavior. A multi-scale finite element (FE) model of the SMSS was developed and validated, the load transfer mechanism of the connection was investigated, and parametric analyses were performed. Test results indicate that failure in the SMSS occurred in the CMU, with modular beams experiencing significant plastic deformation while modular columns remained elastic. The TBC remained within the elastic range, exhibiting semi-rigid behavior, reflecting a strong connection design principle. The load transfer mechanism analysis according to the multi-scale FE model revealed that the BC mainly resists bending, while the PC and bolts transfer shear and tensile forces to maintain connection integrity and deformation compatibility. In addition, parametric analyses were conducted to investigate the influence of key structural components on the seismic behavior of the SMSS. The results within the investigated ranges indicate that increasing the stiffness of modular beams significantly enhances both the lateral stiffness and load-bearing capacity of the SMSS, while modular columns and braces mainly affect the lateral stiffness. In contrast, spaced columns, BC height, and bolt preload have limited effects on the stiffness and load-bearing capacity of the SMSS, with BC height and bolt preload showing greater effects on stiffness than on load-bearing capacity.
To predict the evolution of the elastic modulus of cement paste under high temperatures and overcome the limitations of existing models, which commonly neglect phase evolution–pore interaction effects and fail to establish reliable micro–macro correlations, this study investigates cement pastes with w/c of 0.53 and 0.35. An integrated macro–micro experimental approach, including uniaxial compression tests, XRD, SEM–EDS, and NI, was employed to systematically reveal the underlying mechanisms governing the evolution of mechanical properties, microstructures, and phase transformations of cement paste exposed to temperatures ranging from 20 to 1000 °C. Based on the MT scheme, SC scheme, and Voigt model, a four-step hierarchical homogenization-based multiscale prediction framework was developed. The proposed framework incorporates temperature-dependent mechanisms, including free water evaporation, AFt decomposition, dehydration-induced degradation of C-S-H gel, Ca(OH)2 decomposition, and microcrack propagation. This framework establishes a quantitative cross-scale linkage between nanoscale hydration products and macroscopic elastic modulus, enabling reliable prediction of the temperature-dependent elastic modulus evolution. The results revealed that the mechanical properties of cement paste exhibited a characteristic increase-decrease evolution trend, with 400 °C representing the critical transition temperature. At 800 °C, the elastic modulus underwent a pronounced reduction, primarily attributed to C-S-H gel dehydration, Ca(OH)2 decomposition, and microcrack propagation. The predicted elastic modulus values showed good agreement with experimental measurements, with the average relative error being below 5%. cement pastes with lower w/c ratios demonstrated superior resistance to thermal degradation owing to their initially denser microstructures. This study establishes a quantitative cross-scale relationship between nanoscale hydration products and the elastic modulus of macroscopic cement paste specimens, providing theoretical insights for the safety assessment and repair strategies of fire-damaged concrete structures.
