Upcycling autoclaved aerated concrete into sustainable and energy-efficient geopolymers with improved structural attributes Mohammad Reza Hanafi, Hamed Rahimpour, Zohre Babai Golsefidi, Sahar Zinatloo-Ajabshir, Somayeh Mollaei, Faramarz Moodi, Hamid Zarrabi, Ahmad Fahmi Energy Nexus, 2026 This study aims to achieve the complete recycling of post-demolition autoclaved aerated concrete (AAC) and to develop sustainable, energy-efficient, and high-performance geopolymer construction materials. Recycled AAC powder with different particle sizes was used as the aluminosilicate precursor and mixed with alkaline activators consisting of water glass and sodium hydroxide at concentrations of 4, 8, 12, and 16 mol. The effects of alkaline concentration, activator ratio, curing temperature, and precursor particle size on the mechanical properties and bulk density of the synthesized geopolymer materials were systematically evaluated. Increasing sodium hydroxide concentration and the water glass-to-sodium hydroxide ratio enhanced mechanical strength, while higher curing temperatures decreased bulk density. Under optimal conditions (12 molar sodium hydroxide, activator ratio of 2, curing at 85°C, and a particle size of 150 µm), the compressive, tensile, and flexural strengths reached 27.03, 3.51, and 2.73 MPa, respectively. Water absorption after 24 hours was measured at 11.9 wt.%, and chemical/microstructural analyses revealed a dense and homogeneous matrix consistent with complete geopolymerization. A life cycle assessment demonstrated an 86% reduction in climate-change impact, along with lower resource consumption, water use, and toxicity compared to ordinary Portland cement, confirming the environmental advantages of the proposed approach. Overall, the findings demonstrate that post-demolition AAC can be fully upcycled into structurally efficient and environmentally responsible geopolymer materials, with strong potential for application in sustainable construction products including high-performance precast elements and masonry units.
Development of a novel energy fuse for enhancing blast resistance in masonry infill walls Gholamreza Ostadi Asl, Somayeh Mollaei, Shahram Derogar, Fatemeh Nadiri Soflu, Ceren Ince, Flavio Stochino Engineering Structures, 2026 This study investigates the effectiveness of autoclaved aerated concrete (AAC) blocks as vertically embedded energy fuses for enhancing the blast resistance of masonry infill walls. A novel configuration is proposed, in which AAC layers act as sacrificial and replaceable elements that absorb and redistribute blast energy before it is transmitted through the wall. Validated finite element models were developed to simulate the structural behaviour of infill walls subjected to a wide range of explosive charge weights and standoff distances. Key response parameters, including support reactions, energy dissipation, displacement, velocity, and stress distribution in mortar, brick, and AAC components, were systematically evaluated. The results demonstrate that the AAC fuse system significantly improves blast performance: peak wall displacement was reduced by up to 80 %, base reaction forces by approximately 7 %, and peak stresses in mortar and brick by 59 % and over 30 %, respectively. Additionally, the presence of AAC layers reduced sensitivity to boundary conditions, highlighting its potential in retrofit applications where full anchorage is not feasible. The system also enhanced structural damping, promoted more uniform deformation patterns, and improved energy absorption over time relative to conventional masonry walls. These findings confirm that the proposed AAC energy fuse represents a practical and cost-effective strategy for improving the blast resilience of masonry infill walls, particularly in aging or vulnerable structures where traditional reinforcement methods may be difficult to implement. • A novel AAC fuse system is proposed to enhance blast resistance of infill walls. • FE models simulate response under various TNT loads and standoff distances. • The AAC fuse reduces displacement, base force, and stresses in walls significantly. • Performance is less sensitive to boundary conditions and anchorage limits. • AAC boosts energy absorption and enables low-cost, sustainable retrofitting.
Nonlinear Seismic Performance Evaluation of Hybrid Base Isolation Systems Peyman Narjabadifam, Somayeh Mollaei, Ehsan Noroozinejad Farsangi, Majid Khataei Journal of Structural Design and Construction Practice, 2025 A variety of base isolation systems and their combinations with dampers are applicable in practice. However, most previous studies focused on few numbers of the isolation systems. Therefore, a more comprehensive investigation is crucial. All the possible variations of hybrid base isolation configurations had inspired this research. Seismic performance of the series and parallel hybrid base isolation systems were extensively investigated in the current research using commercially available software. The studied hybrid systems were included lead rubber bearings (LRBs) in combined with linear or nonlinear dampers at base or superstructure levels. The high-damping rubber bearings (HDRBs), the friction pendulum systems (FPS), and a fixed-base reference structure were also investigated and compared. The considered earthquake records were selected in four major groups including far-field, near-field with fling step, near-field with forward directivity for the normal component, and near-field with forward directivity for the parallel component. Based on the main results, the FPS system had least sensitivity to the earthquake frequency content. In contrast, the LRB with linear damper at superstructure level was the most sensitive system to the frequency content of the earthquakes. The LRB combination in parallel with a flat sliding (FS) system showed a better performance in controlling the acceleration and residual displacement responses compared with FPS. Besides, the isolation systems with linear dampers performed better than the nonlinear ones under all the earthquake groups. Results proved that augmented dampers (both linear and nonlinear) at the isolation level had more enhancing effects than the HDRB system alone. Generally, adding dampers to the base level was more effective than that of the superstructure level. The LRB combined with linear damper was the most effective combination in controlling the isolation residual displacement response.
A Numerical Method for Estimating the Dynamic Response of Structures مهدی بابایی, میثم جلیل خانی, سمیه ملایی Journal of Civil and Environmental Engineering, 2025 A novel numerical method is proposed for computing the seismic response of linear and nonlinear systems. Single-degree-of-freedom (SDOF) and multi-degree-of-freedom (MDOF) systems are covered. The method is called load impulse method (LIM) because it uses the load impulse concept in its formulation. LIM is first extended for analyzing linear damped systems whose damping ratios are almost greater than 1% and nonlinear systems in general. To formulate LIM, the governing differential equation of motion (DEOM) is modified to have appropriate form for numerical integration. Then, it is integrated over time step using trapezoidal integration rule. Rearranging the obtained equation, the required relations are generated for computing seismic response of dynamic systems through simple iteration. The seismic response of several linear and nonlinear structural systems under dynamic loads is determined through the proposed LIM. A detailed comparison is then carried out between the results of LIM and those obtained from Duhamel integral, Newmark-β, and Wilson-θ methods. The results clearly show that the proposed LIM can robustly estimate the displacement, velocity, and acceleration time-histories of the dynamic systems within satisfactory computational cost.
Comparative probability-based seismic safety assessment of base-isolated buildings: A case study , Peyman Narjabadifam, Somayeh Mollaei, , Ehsan Noroozinejad, , Mehdi Babaei, , Navid Mousavi, and Advances in Civil and Architectural Engineering, 2024 Seismic fragility curves are used to assess the structural vulnerability probability at various damage states. In this study, the effects of different isolation systems on the seismic safety of a two-dimensional reinforced concrete moment-resisting frame are investigated. The reference structure was a hotel building in California, USA. A comparative probability-based seismic safety assessment for building components was conducted on the superstructure hypothetically fitted with various isolation systems. In this regard, two categories of isolation systems, including rubber‐ and friction‐based systems, were selected. The high damping rubber bearings and friction pendulum systems were considered. Incremental dynamic analyses were conducted for a suite of earthquake records to develop the fragility curves considering modelling, demand, and capacity uncertainties. Based on the results, it was observed that the building failure probability reduction was influenced by the seismic isolation systems rather than the fixed base (un-retrofitted) model. Furthermore, the high damping rubber bearings system was found to be more reliable than the friction pendulum system in the limit states considered. However, no significant discrepancy was observed in the performance of the building fitted with isolation systems at higher damage states.
Experimental-Numerical Assessment of Mechanical Behavior of Laboratory-Made Steel and NiTi Shape Memory Alloy Wire Ropes Peyman Narjabadifam, Neda Fazlalipour, Somayeh Mollaei, Mohammad Momeni, Ali Saman Watandoust, Mahdi Chavoshi, Alireza Babaeian Amini, Farshad Karazmay Buildings, 2024 The mechanical behaviors of laboratory-fabricated steel and superelastic shape memory alloy (SMA) wire ropes are assessed in this study through a comprehensive approach encompassing both experimental investigations and finite element (FE) numerical simulations. The assessment of steel wire ropes involves experimental scrutiny under sinusoidal cyclic loading and natural earthquake loading conditions. In parallel, SMA wire ropes’ behaviors are analyzed utilizing FE simulations employing the widely acknowledged ABAQUS software version 2020. The validation of all numerical simulations is undertaken against the experimentally observed behaviors. Moreover, full-scale steel wire ropes are subjected to shaking table tests to validate the simulations, facilitating a comparative analysis between the mechanical responses of SMA and steel wire ropes. The findings demonstrate that SMA wire ropes exhibit superelastic behavior akin to SMA wires, with marginal variations in overall response observed across distinct configurations, akin to steel wire ropes. Furthermore, augmenting the helix angle of SMA wire ropes results in reduced stress and increased strain when exposed to the El Centro earthquake scenario. Nevertheless, the mechanical response of SMA wire ropes closely mirrors that of a single wire.
Design of lead-rubber-bearing isolation systems using a grasshopper optimisation algorithm Somayeh Mollaei, Ehsan Noroozinejad Farsangi, Mehdi Babaei, Fatemeh Mehri, Fakhraddin Ghahramani Proceedings of the Institution of Civil Engineers Forensic Engineering, 2023 Seismic isolation is an efficient method for improving the seismic behaviour of building structures. Sensitivity analysis of the behaviour of base-isolated structures is essential for investigating the effects of various mechanical and environmental factors on the performance of seismic isolation systems. In this study, the optimal design of a lead-rubber-bearing seismic isolation system was investigated by considering irregular mass conditions and near-fault seismic excitation. The grasshopper optimisation algorithm was used to optimise the design of the isolation system. Sensitivity analysis of the seismic response of the isolated structures was carried out for the mechanical parameters of the isolation system, mass irregularity in the building and near-fault earthquakes. The results proved the efficiency of the algorithm in optimal design problems for structural isolation systems. Also, the sensitivity analysis of the seismic behaviour of base-isolated structures showed that the yield base shear index had the most important effects in analysis. Furthermore, mass irregularity showed a negligible influence on the behaviour of the isolated structures.
Application of a Novel Optimization Algorithm in Design of Lead Rubber Bearing Isolation Systems for Seismic Rehabilitation of Building Structures F. Mehri, S. Mollaei, E. Noroozinejad Farsangi, M. Babaei, F. Ghahramani International Journal of Engineering Transactions A Basics, 2023 Various mechanical and geometrical parameters have different effects on the isolation system's performance. Thus, a sensitivity study of the isolated structures' behavior is an essential matter. In this regard, the isolation systems should be designed using optimization approaches to consider the effects of the different factors. In this study, the optimal design of the lead rubber bearing (LRB) seismic isolation was conducted by considering mass irregularity and near-fault seismic excitation effects. Also, sensitivity analysis of the behavior of the considered isolated buildings was implemented concerning the mechanical parameters of the LRB system. A nonlinear time history dynamic analysis was used here, and the design optimization of the LRB isolator was programmed using the newly introduced grasshopper optimization algorithm (GOA). The main purpose was to investigate the ability of the GOA to optimize the design parameters of the LRB-isolated frames. The results proved the desirable ability of the GOA to solve optimal design problems for isolation systems. Also, the sensitivity analysis of the seismic behavior of LRB base-isolated structures showed that the yield base shear index had the most important effects. Also, the mass irregularity parameter showed a negligible influence.
A Predictive Model for the Strength of a Novel Geopolymer Construction Material Produced by Autoclaved Aerated Concrete Waste , Somayeh Mollaei, Ahmad Fahmi, , Davoud Jahani, , Zohre Babaei Golsefidi, , Reza Babaei, , Mohammad Reza Hanafi, and International Journal of Sustainable Construction Engineering and Technology, 2023 Carbon dioxide emission and consumption of large amounts of natural resources are the environmental hazards observed in the production process of various commonly used construction materials, like Portland cement and clay bricks. Also, debris from the demolition of old buildings and disposing of the waste of construction material factories also cause environmental pollution. Producing environmentally friendly geopolymer materials with recycling construction wastes containing aluminosilicate resources and alkaline activators could be an effective method for reduction of environmental hazards. This paper is an innovative feasibility study of geopolymer material production using the waste autoclaved aerated concrete (AAC) powder. Here, a mix of AAC powder together with activator solution containing sodium hydroxide and sodium silicate at different concentrations was used to prepare the geopolymer mortar samples. The specimens were oven-cured at different temperatures. The effects of sodium hydroxide concentration and curing temperature on the compressive, tensile, and flexural strengths, as well as water absorption of the samples, were investigated. The main contribution of this study is the feasibility of the successful fabrication of geopolymer material based on AAC waste powder with desirable mechanical properties. Namely, the compressive strength of the base AAC blocks used here was 3 MPa and the maximum strength of the produced geopolymer material using the AAC powder was about 21 MPa. The test results were used to develop a model to predict the compressive strength of the proposed geopolymer AAC material to the effective parameters by Gene Expression Programming. The model predictions were confirmed using an extra series of test results implemented by the authors.
Development of analytical models for RC columns under blast loading considering strain rate effects International Journal of Integrated Engineering, 2017
RECENT SCHOLAR PUBLICATIONS
Experimental Investigation of the Effect of Nano materials on the Dynamic Properties of Cemented Fine-Grained Soils S Mollaei, GR Ostadi Asl, M Mollaei, S Taheri, S Nasri Journal of Civil and Environmental Engineering , 2026 2026
Development of a novel energy fuse for enhancing blast resistance in masonry infill walls GO Asl, S Mollaei, S Derogar, FN Soflu, C Ince, F Stochino Engineering Structures 349, 121837 , 2026 2026 Citations: 1
Upcycling autoclaved aerated concrete into sustainable and energy-efficient geopolymers with improved structural attributes MR Hanafi, H Rahimpour, Z Babai Golsefidi, S Zinatloo-Ajabshir, ... Energy Nexus 21 (2026), 100685 , 2026 2026 Citations: 5
Energy Nexus MR Hanafi, H Rahimpour, ZB Golsefidi, S Zinatloo-Ajabshir, S Mollaei, ... Energy 21 (10068), 5 , 2026 2026
Investigation of the Simultaneous Effects of Seismic and Explosive Loading in RC Frames G Ostadi-Asl, S Mollaei, A Shah Mohammadi Journal of Civil and Environmental Engineering 55 (120), 75-88 , 2025 2025
Nonlinear seismic performance evaluation of hybrid base isolation systems P Narjabadifam, S Mollaei, E Noroozinejad Farsangi, M Khataei Journal of Structural Design and Construction Practice 30 (2), 04025003 , 2025 2025 Citations: 2
The Factors Affecting the Implementation of Building Retrofitting Projects in East Azerbaijan Province, Iran S Mollaei, M Babaei, B Khalili, M Khezri Disaster Prevention and Management Knowledge (quarterly) 14 (4), 496-521 , 2025 2025
A numerical method for estimating the dynamic response of structures M Babaei, M Jalilkhani, S Mollaei Journal of Civil and Environmental Engineering 55 (1), 1-19 , 2025 2025 Citations: 8
Experimental-Numerical Assessment of Mechanical Behavior of Laboratory-Made Steel and NiTi Shape Memory Alloy Wire Ropes P Narjabadifam, N Fazlalipour, S Mollaei, M Momeni, AS Watandoust, ... Buildings 14 (6), 1567 , 2024 2024 Citations: 3
Design of lead-rubber-bearing isolation systems using a grasshopper optimisation algorithm S Mollaei, EN Farsangi, M Babaei, F Mehri, F Ghahramani Proceedings of the Institution of Civil Engineers-Forensic Engineering 177 … , 2024 2024 Citations: 4
Comparative probability-based seismic safety assessment of base-isolated buildings: A case study P Narjabadifam, S Mollaei, EN Farsangi, M Babaei, N Mousavi Advances in Civil and Architectural Engineering 15 (28), 33-49 , 2024 2024 Citations: 3
Numerical analysis of seismic behavior of an arched-roof 3D-Printed building P Narjabadifam, S Mollaei, E Farsangi, S Talebi Gradjevinski Mater. i Konstr 67 (1), 1-15 , 2024 2024 Citations: 3
Application of a novel optimization algorithm in design of lead rubber bearing isolation systems for seismic rehabilitation of building structures F Mehri, S Mollaei, EN Farsangi, MH Babaei, F Ghahramani International Journal of Engineering, Transactions C: Aspects 36 (3), 594-603 , 2023 2023 Citations: 8
Code-based study of pounding prevention between adjacent buildings P Narjabadifam, S Mollaei, M Babaei, N Shahmahammadi Journal of Structural and Construction Engineering 9 (12), 81-100 , 2023 2023
A predictive model for the strength of a novel geopolymer construction material produced by autoclaved aerated concrete waste S Mollaei, A Fahmi, D Jahani, ZB Golsefidi, R Babaei, MR Hanafi International Journal of Sustainable Construction Engineering and Technology … , 2023 2023 Citations: 12
Comparative Probability Based Seismic Safety Assessment of Base Isolated Building Frames P Narjabadifam, S Mollaei, M Babaei, N Mousavi 2023 Citations: 1
Torsional buckling of functionally graded graphene reinforced composite laminated cylindrical panel: S. Mollaei et al. S Mollaei, M Babaei, K Asemi Archive of Applied Mechanics 93 (2), 427-435 , 2023 2023 Citations: 56
Investigation of behavior of masonry walls constructed with autoclaved aerated concrete blocks under blast loading S Mollaei, R Babaei Ghazijahani, E Noroozinejad Farsangi, D Jahani Applied Sciences 12 (17), 8725 , 2022 2022 Citations: 21
New methods for dynamic analysis of structural systems under earthquake loads M Babaei, M Jalilkhani, SH Ghasemi, S Mollaei Journal of Rehabilitation in Civil Engineering 10 (3), 81-99 , 2022 2022 Citations: 14
Laboratory study of high-resistance laterite-based geopolymer bricks S Mollaei, Y Marabi, A Fahmi, AR Babaeian International Journal of Integrated Engineering 14 (1), 240-250 , 2022 2022 Citations: 7
MOST CITED SCHOLAR PUBLICATIONS
Free vibration analysis of FG porous joined truncated conical-cylindrical shell reinforced by graphene platelets F Kiarasi, M Babaei, S Mollaei, M Mohammadi, K Asemi Advances in nano research 11 (4), 361-380 , 2021 2021 Citations: 59
Torsional buckling of functionally graded graphene reinforced composite laminated cylindrical panel: S. Mollaei et al. S Mollaei, M Babaei, K Asemi Archive of Applied Mechanics 93 (2), 427-435 , 2023 2023 Citations: 56
Investigation of axial strengthened reinforced concrete columns under lateral blast loading M Esmaeilnia Omran, S Mollaei Shock and vibration 2017 (1), 3252543 , 2017 2017 Citations: 31
Investigation of behavior of masonry walls constructed with autoclaved aerated concrete blocks under blast loading S Mollaei, R Babaei Ghazijahani, E Noroozinejad Farsangi, D Jahani Applied Sciences 12 (17), 8725 , 2022 2022 Citations: 21
Numerical solution of beam equation using neural networks and evolutionary optimization tools M Babaei, A Atasoy, I Hajirasouliha, S Mollaei, M Jalilkhani Adv Comput Des 7 (1), 1-17 , 2022 2022 Citations: 15
New methods for dynamic analysis of structural systems under earthquake loads M Babaei, M Jalilkhani, SH Ghasemi, S Mollaei Journal of Rehabilitation in Civil Engineering 10 (3), 81-99 , 2022 2022 Citations: 14
Spreading, fingering instability and shrinking of a hydrosoluble surfactant on water S Mollaei, AH Darooneh Experimental Thermal and Fluid Science 86, 98-101 , 2017 2017 Citations: 13
A predictive model for the strength of a novel geopolymer construction material produced by autoclaved aerated concrete waste S Mollaei, A Fahmi, D Jahani, ZB Golsefidi, R Babaei, MR Hanafi International Journal of Sustainable Construction Engineering and Technology … , 2023 2023 Citations: 12
Preparing pressure-impulse diagrams for reinforced concrete columns with constant axial load using single degree of freedom approach RA Izadifard, S Mollaei, MEN Omran International Journal of Advancements in Technology 7 (4), 9 , 2016 2016 Citations: 10
Assessment of empirical formulas for estimating residual axial capacity of blast damaged RC columns ME Omran, S Mollaei European Journal of Sustainable Development 6 (3), 383-383 , 2017 2017 Citations: 9
A numerical method for estimating the dynamic response of structures M Babaei, M Jalilkhani, S Mollaei Journal of Civil and Environmental Engineering 55 (1), 1-19 , 2025 2025 Citations: 8
Application of a novel optimization algorithm in design of lead rubber bearing isolation systems for seismic rehabilitation of building structures F Mehri, S Mollaei, EN Farsangi, MH Babaei, F Ghahramani International Journal of Engineering, Transactions C: Aspects 36 (3), 594-603 , 2023 2023 Citations: 8
Laboratory study of high-resistance laterite-based geopolymer bricks S Mollaei, Y Marabi, A Fahmi, AR Babaeian International Journal of Integrated Engineering 14 (1), 240-250 , 2022 2022 Citations: 7
Assessment of damage and residual load capacity of the normal and retrofitted rc columns against the impact loading S Mollaei, M Babaei, M JalilKhani Journal of Rehabilitation in Civil Engineering 9 (1), 29-51 , 2021 2021 Citations: 7
INVESTIGATING THE EFFECTS OF FLIPPED METHOD IN ONLINE COURSE ON STUDENTS'LEARNING AND SATISFACTION DURING COVID-19 PANDEMICA CASE STUDY: TECHNICAL ENGLISH COURSE FOR CIVIL … S Mollaei, ZF Ajabshir Majallah-i Amuzih-i Muhandisi-i Iran 23 (89), 113-6 , 2021 2021 Citations: 6
Estimation of RC columns’ response under the effect of lateral blast loading by SDOF method and comparison with FEM M Esmaeil Nia Omran, S Mollaei Journal of Structural and Construction Engineering 4 (3), 81-90 , 2017 2017 Citations: 6
Upcycling autoclaved aerated concrete into sustainable and energy-efficient geopolymers with improved structural attributes MR Hanafi, H Rahimpour, Z Babai Golsefidi, S Zinatloo-Ajabshir, ... Energy Nexus 21 (2026), 100685 , 2026 2026 Citations: 5
Design of lead-rubber-bearing isolation systems using a grasshopper optimisation algorithm S Mollaei, EN Farsangi, M Babaei, F Mehri, F Ghahramani Proceedings of the Institution of Civil Engineers-Forensic Engineering 177 … , 2024 2024 Citations: 4
IDENTIFICATION AND ANALYSIS OF THE STRATEGIC DRIVERS OF ENTREPRENEURIAL UNIVERSITY USING BY CROSS IMPACT ANALYSIS APPROACH S Mohammadpour, H Salarzehi, AR Kamalian, NM Yaghoubi, M Mehdi Iranian Journal of Engineering Education 23 (89), 133-156 , 2021 2021 Citations: 4
Experimental-Numerical Assessment of Mechanical Behavior of Laboratory-Made Steel and NiTi Shape Memory Alloy Wire Ropes P Narjabadifam, N Fazlalipour, S Mollaei, M Momeni, AS Watandoust, ... Buildings 14 (6), 1567 , 2024 2024 Citations: 3
