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NANO-ENGINEERED NA-BENTONITE THIN FILM MEMBRANES FOR SUSTAINABLE WATERPROOFING OF CIVIL STRUCTURES

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Waterproofing remains a critical challenge in the durability and service life of concrete infrastructure, particularly in environments exposed to moisture ingress and shrinkage-induced cracking. Conventional bentonite-based systems, while effective, often require high material consumption and may exhibit limitations in performance consistency. This study explores the development of nano-Na-bentonite derived from Egyptian bentonitic clay through solvothermal (NBS) and precipitation (NBP) synthesis routes. By leveraging nano-scale engineering, the research aims to enhance swelling behavior, hydrophobicity, and crack-sealing efficiency, ultimately offering a sustainable and high-performance alternative for waterproofing civil structures. Material Preparation and Nano-Modification Techniques The starting Egyptian bentonite was subjected to activation and purification processes to ensure the removal of impurities and optimization of montmorillonite content prior to nano-modification. Two s...
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Neural Backstepping Output-Constrained Control for Flexible Civil Aircraft Overload Tracking

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Ride quality and flight safety are critical performance indicators for flexible civil aircraft, particularly under atmospheric disturbances such as gusts and turbulence. Normal overload tracking must satisfy stringent comfort and safety standards defined by ISO 2631-1 and MIL-F-9490D. This paper proposes a neural backstepping output-constrained control strategy to ensure accurate overload tracking while strictly respecting ride quality constraints. Normal Overload Constraints and Control Objectives The normal overload constraint arises from the need to limit excessive accelerations that degrade passenger comfort and structural integrity. To explicitly address these constraints, the control design incorporates an integral barrier Lyapunov function (IBLF), which guarantees that the overload response remains within a predefined safe interval throughout system operation. Neural Backstepping Control Framework A backstepping-based control architecture is developed for the flexible aircr...
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Intelligent Infrastructure Crack Detection Using MSEDBO-Optimized Deep Learning

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  Infrastructure surface crack detection is a vital task in structural health monitoring, directly influencing the safety, durability, and serviceability of civil engineering assets. Although deep learning methods have achieved notable success in automated crack detection, their performance is often constrained by inefficient hyperparameter tuning, susceptibility to local optima, and suboptimal feature extraction. This study addresses these limitations by proposing an intelligent optimization-driven crack detection framework. Limitations of Conventional Deep Learning-Based Crack Detection Traditional deep learning models rely heavily on manual or heuristic-based hyperparameter selection, which can lead to unstable training outcomes and reduced generalization performance. Moreover, commonly used optimization techniques may become trapped in local optima, resulting in inaccurate crack localization and increased false positive rates, particularly when dealing with complex backgroun...
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Thermal Feasibility of Ground Source Heat Pump Systems for Civil Defense Facilities

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Persistently high cooling loads and strict safety requirements make thermal regulation in civil defense facilities particularly challenging. Conventional cooling systems often struggle to meet long-term efficiency, reliability, and concealment demands. This study evaluates the thermal feasibility of a ground source heat pump (GSHP) system with high concealment for application in the Zhushan civil defense facility in Nanjing, China, aiming to assess its suitability for managing continuous and intensive cooling demands. Numerical Modeling of Ground Heat Exchange A three-dimensional numerical model was developed to simulate coupled flow and heat transfer processes within the ground heat exchanger (GHE). The model incorporates unsaturated porous soil conditions, time-varying fluid flow rates, and environmental disturbances, enabling realistic representation of heat transfer between the circulating fluid, grout, and surrounding soil. This modeling framework provides a robust basis for eval...
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Sustainable Rockfall Protection Using Recycled Tyres for Enhanced Impact Resistance

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  Rockfall hazards present a serious risk to infrastructure in mountainous and hilly regions, demanding mitigation systems that are both mechanically robust and economically viable. Reinforced concrete rockfall barriers are commonly used, yet their performance under high-energy impacts depends heavily on energy-absorbing components. This study investigates innovative and sustainable approaches to enhance rockfall barrier performance, with a particular focus on replacing conventional materials with recycled alternatives. Numerical Modelling of Rockfall Impact A detailed finite element model of a double-anchored reinforced concrete rockfall barrier was developed using Abaqus/Explicit. The barrier was subjected to a high-velocity impact of 25 m/s from a 1 m diameter spherical rock, representing severe rockfall conditions. This numerical framework enabled accurate simulation of impact dynamics, deformation behavior, and energy dissipation mechanisms within the barrier system. Perfo...
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Accident Causality Analysis of Steel Structure Collapses During Construction

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Accidents in the construction sector are widely studied from the perspective of occupational safety, with emphasis on fatalities and injuries. However, construction accidents also have profound impacts on construction processes, project continuity, and structural integrity. Among these, steel structure collapses during construction represent critical events that require systematic investigation. This study addresses this gap by conducting a comprehensive analysis of the causes of steel structure collapses during construction. Steel Structure Collapses as Process Failures Structural collapses during construction are not isolated incidents but complex failures arising from multiple interacting factors. These events often disrupt construction workflows, cause economic losses, and undermine public confidence in engineering practices. Understanding collapses as process-related failures allows for a broader safety perspective beyond individual worker-related incidents. AcciMap Framework f...
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Phosphate Biomineralisation for Sustainable Biocementation in Civil and Geoenvironmental Engineering

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Over the past two decades, biocementation has emerged as a promising technique for ground improvement, crack healing, and the restoration of building materials and heritage stones. Most existing research has focused on calcite-based biocements produced through urea-hydrolysis pathways. However, the generation of ammonia by-products and limited durability in acidic environments restrict the large-scale and sustainable application of these methods. This review introduces phosphate biomineralisation as a novel and environmentally favorable alternative. Limitations of Conventional Calcite-Based Biocementation Microbially induced carbonate precipitation (MICP) and enzymatically induced carbonate precipitation (EICP) rely heavily on urea hydrolysis, which produces ammonia that must be treated or removed. This not only increases environmental risk but also raises operational costs. Additionally, carbonate-based biocements exhibit reduced durability under acidic conditions, limiting their ap...
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