The development of sustainable structural materials is critical for reducing the environmental impact of construction. This study investigates lightweight geopolymer concrete (LWGC) incorporating expanded perlite aggregate (EPA) at 0–20% replacement of fine aggregate. Fresh and hardened properties, including workability, density and compressive and flexural strengths, are evaluated experimentally, while the modulus of elasticity is determined empirically. Microstructural investigation is conducted to examine the interaction between EPA and the geopolymer matrix. Finite element analysis (FEA) is employed to evaluate structural response under seismic loading using experimentally derived material properties. The experimentally observed porosity and stiffness reduction due to lower modulus of elasticity, were reflected in the seismic response analysis, demonstrating enhanced damping capacity. Existing studies on LWGC with EPA primarily address density reduction and strength development, with limited consideration of seismic performance. The results indicate that increasing EPA content improves workability and reduces density while maintaining adequate mechanical properties.
Construction sector is a major contributor to global CO₂ emissions, largely due to the production of cement, which are highly energy-intensive. In present investigation, the fresh and hardened properties of cement mortar reinforced with Abutilon indicum fibres was studied by varying the proportions of GGBS (10%, 20%, and 30%) and Microsilica (2.5%, 5%, 7.5%, and 10%). The treated fibre reinforced cement mortar blended with 10% GGBS and 5% Microsilica in partial substitution of cement was found to be the optimal combination with 12.5%, 9.1% and 18.2% increase in compressive, flexural and tensile strengths. Also, GGBS and MS demonstrate a significant interactive effect with p-value less than 0.05, contributing not only independently to the improvement of the mechanical properties but also enhancing this effect through synergistic interactions. Hence, blended cement mortar featuring Abutilon indicum fibres aids in maintaining the integrity and promoting the long-term performance of composites for sustainable construction applications.
This study investigates the cyclic behavior of double-tee moment connections without shear tabs using European steel profiles. A three-dimensional finite element model was developed in ANSYS Workbench and validated against experimental results. The model included material and geometric nonlinearities, contact interactions, bolt pretension, and a Chaboche kinematic hardening model to simulate cyclic inelastic behavior. A parametric study examined the effects of T-flange and T-stem thickness, bolt spacing, continuity and doubler plates, reinforcing plates, beam web stiffeners, and circular web openings. Connection performance was evaluated in terms of rotational stiffness, moment capacity, energy dissipation, stress distribution, and plastic hinge formation. Artificial neural network (ANN) models were also developed to predict monotonic and cyclic response parameters. The results show that T-flange thickness and local reinforcement details most significantly improve seismic performance, while bolt spacing has a limited influence. ANN models provided accurate and efficient predictions for preliminary connection assessment.
Urban road networks are critical for maintaining accessibility and emergency response after earthquakes, particularly in densely built areas. This study examines how the spatial pattern of earthquake-induced road blockages affects the structural resilience of a road network in Istanbul. The intact network was compared with two hypothetical scenarios in which the same number of links was blocked, either in a dispersed or localized pattern. Connectivity, intersection density, and changes in network shape across spatial scales were evaluated together. Results show that the spatial arrangement of blocked roads strongly influences network response. Dispersed disruption caused a much larger loss of high-density intersection areas, whereas localized disruption produced a greater reduction in network redundancy while preserving much of the original dense structure. Both scenarios also simplified the spatial organization of the surviving network. Combining these complementary indicators provides a basis for identifying vulnerable road networks and supporting post-earthquake transport planning.
This study investigates the dynamic properties of fiber-reinforced rubberized recycled concrete incorporating recycled coarse aggregate (RCA), crumb rubber (CR), and polypropylene (PP) fiber through free vibration testing. Nine reinforced concrete columns (150 × 150 × 950 mm) incorporating 30% RCA, 0%–15% CR, and 0%–0.5% PP fiber were prepared and tested under three impact energies. The measured acceleration responses were used to evaluate natural frequency, time period, damping ratio, and damping coefficient. Results showed that CR increased the displacement and natural time period. Although the damping ratio increased with CR content, the damping coefficient decreased beyond a certain CR percentage due to reduced natural frequency. On the contrary, incorporating fiber reduced displacement, enhanced the damping ratio and damping coefficient, and maintained time periods comparable to conventional concrete. Moreover, the curvature ductility improved further by incorporating fiber in addition to CR. This study concludes that PP fiber can improve the dynamic performance of rubberized recycled concrete for sustainable structural applications.
