2026· Journal of materials in civil engineering· Vol 38· 0 citations· 32 references
Abstract
Design guidance for 3D-printed concrete (3DPC) is constrained by lack of a reliable method to estimate compressive capacity from conventional cast-cube results, particularly for hollow, shell-dominated elements typical of printed walls. This study addresses that gap using representative double-shell hollow cubes with controlled surface slopes (0°, 10°, 20°) to isolate shell load paths and texture-induced eccentricity. Under axial loading, the 0° specimens attained approximately 50% of the cast-cube strength, reflecting cavity-driven load redistribution and interlayer weakness. Introducing slopes further reduced capacity: at 28 days, 10° and 20° cases achieved roughly 37% and 33% of the cast control, respectively. Finite-element analyses corroborated a mechanism of load-path eccentricity, tensile hoop stress, and interface-localized damage near peaks. Based on the experimental matrix, we propose an empirical mapping from cast-cube strength to 3DPC capacity within the tested slope range; the relation provides intentionally conservative lower-bound estimates, underpredicting measured strengths by
∼
12
%
–19% at 14–28 days within the test domain. The findings clarify how hollow cores and surface slopes govern load paths and failure localization in printed shells and provide a practical estimator to support early-stage sizing, material screening, and conservative preliminary design of walls with hollow cores and textured surfaces without requiring full-scale tests under typical conditions.
Evaluating the density-specific compressive performance of metal matrix syntactic foams (MMSFs) is essential for engineering design. Existing data show that density-specific compressive strength depends on materials (matrices and fillers), manufacturing route, and loading conditions. An Ashby-style map compares energy absorption per volume (W) and specific energy absorption (SEA) across different MMSF systems. Functionally graded MMSFs are reviewed for controlling collapse sequence under quasi-static, dynamic, impact, and cyclic loading. Typical failure modes are discussed in terms of localized shear-band failure and diffuse progressive collapse. Besides, this review also discusses analytical and numerical modeling methods for predicting MMSF compressive properties. Analytical models, typically based on Gibson–Ashby theory, reveal density–property relationships but are limited for complex microstructures or nonlinear deformation. Numerical models, especially CT reconstruction-based methods, capture realistic microstructural features and offer greater predictive flexibility. Future work should combine analytical and numerical models to predict density-specific compressive strength more quickly and accurately, supporting MMSF design.
Wanrong Du, I. N. Orbulov· Journal of materials enginee...· 0 citations
Analytical modeling and numerical simulations are employed in this study to examine the plastic behavior of fully clamped foam-filled hexagonal core sandwich beams (FHCSBs) under transverse loading. A yield criterion is developed for the FHCSB cross-section by considering the combined strength contributions of the folded plates and the metallic foam filler. By coupling this criterion with the associated flow rule, an analytical model is developed to predict the large-deflection behavior of FHCSB, specifically accounting for the interaction between bending and axial stretching. To verify the theoretical framework, numerical calculations using Abaqus/Explicit software are performed. The results show that the analytical predictions for post-yield response match the numerical results for both mid-span and offset loading cases. Additionally, a parametric study investigates how face-sheet thickness, foam strength, and cell inclination angle influence the structural performance. The analysis indicates that face-sheet thickness is the primary factor determining the membrane hardening rate, whereas the hexagonal core configuration offers a stable cushioning effect during early-stage deformation. This analytical approach provides an effective tool for assessing the load-carrying capacity and energy absorption of FHCSB structures.
Yiming Cao, Xilin Luo, Yao Wang et al.· International Journal of Pro...· 0 citations
Three-dimensional printed concrete (3DPC) exhibits anisotropic mechanical behaviour due to layer-wise extrusion, yet a standardised methodology for estimating constitutive model parameters from full-field experimental data remains absent. This study presents a digital image correlation (DIC)-based approach for estimating the elastic modulus and compressive strength of 3DPC from uniaxial compression tests. Six printing groups and one cast control were fabricated, with three groups spanning the nozzle diameter extremes prioritised for complete DIC re-analysis. Full-field surface strain was acquired using a custom interactive Ncorr batch pipeline, with verified region-of-interest selection. The secant elastic modulus, derived from DIC displacement gradients, was 27 ± 3 GPa (15 mm nozzle), 17 GPa (30 mm nozzle), and 22 ± 6 GPa (cast control). Preliminary Poisson ratio estimates of 0.16 and 0.17 were obtained from two specimens. Full-field strain maps revealed greater heterogeneity in the printed specimens than in the cast controls. Results indicate that the choice of nozzle diameter impacts both strength and stiffness, with a 59% increase in each when reducing the nozzle diameter from 30 mm to 15 mm at constant layer height. This approach provides preliminary estimates from a single test, though validation against direct extensometry is recommended before its application to structural simulations.
Fenghua Yuan, Mingyang Feng, Lifang Han et al.· Buildings· 0 citations
Sixteen reinforced concrete beams were tested under symmetric concentrated loading to investigate the mechanical behavior of beams designed using the compressive force path (CFP) method, in comparison with specimens designed according to the Chinese Code for Design of Concrete Structures (GB 50010-2010). The test variables included shear-span ratios (4.0, 3.0, 2.5, and 2.0) and sectional dimensions (150 × 300 mm and 250 × 550 mm). The test process and test results were systematically analyzed. The results show that the stress transmitted along the compressive force path is the main factor governing the shear capacity. The CFP beams achieved peak loads comparable to those of the GB beams while using 5.88–39.99% fewer stirrups, with larger savings observed for smaller shear-span ratios. The CFP method predicted the shear capacity with an error of approximately 10% (ranging from 2.24% to 12.45%). The shear strength of the CFP beams decreased with increasing shear-span ratio and effective depth. Overall, the CFP-designed specimens met the expected mechanical performance requirements, verifying the accuracy and applicability of the CFP method.
Lightweight aggregate concrete reduces structural dead load but generally exhibits lower compressive strength and ductility than normal-weight concrete. This study experimentally evaluates the effectiveness of carbon-fibre-reinforced polymer (CFRP) confinement for low-density lightweight aggregate concrete, an area in which data for square sections remain limited. Twelve 300-mm-high specimens with a density of approximately 1550 kg/m³ were tested under monotonic concentric compression. The investigated parameters were concrete compressive strength (15 and 28 MPa), cross-sectional shape (square and circular), and number of CFRP layers (one and two). Failure occurred through localized, extensive, or hoop rupture of the CFRP. The confined specimens exhibited approximately bilinear stress–strain responses and substantial improvements in strength and deformation capacity. For square specimens with 15 MPa concrete, two CFRP layers increased the average strength ratio to 2.27 and the strain ratio to 23.39. Circular specimens developed greater confinement efficiency, reaching an average strength ratio of 3.76 with two layers. Lower-strength concrete showed larger relative ductility gains than higher-strength concrete. These findings demonstrate that CFRP confinement can substantially reduce the brittle response of low-density lightweight concrete and support its use in lightweight, resilient, and earthquake-resistant structural applications.
This study experimentally and analytically investigated the structural performance of hollow reinforced concrete columns (HRCCs) subjected to eccentric compressive loading (
e
/
h
=
0.5
). Three specimens with equal concrete cross-sectional areas and slenderness, differing only in geometry and void ratio, were tested. The results showed that the hollow columns outperformed the solid specimen, achieving up to 35% higher ultimate load and 49% greater energy absorption. Although the crack widths increased in the hollow sections, they remained within the American Concrete Institute’s durability limits, and the cracking behaviors were comparable. Analytical predictions showed good agreement with the experimental results, and the normalized moment interaction diagrams clearly demonstrated that the hollow sections outperformed the solid sections in axial–moment capacity across all eccentricity ratios (
e
/
h
). These findings highlight the geometric efficiency of HRCCs under combined axial and bending effects owing to eccentric loading, offering improved strength and energy dissipation without a significant compromise in stiffness or ductility.
Hussein Ali Al-Bahadli, A. Y. Ali· Journal of Structural Design...· 0 citations