The durability and security of reinforced concrete (RC) structures, particularly in chloride-rich environments, rely significantly on structural health monitoring (SHM). This study examines corrosion monitoring in high yielding strength deformed steel (HYSD) 500 grade Rebars and epoxy coated steel bars exposed to chloride ingress using the electro-mechanical impedance (EMI) technique. Before immersing the steel bars in chloride solutions, simulating marine or de-icing conditions, baseline impedance readings were recorded using piezoelectric sensors attached to the rebars. Impedance data was then continuously collected to track corrosion related changes in mechanical properties. The initial findings reveal distinct impedance patterns for the two types of steel bars. Compared to HYSD 500 grade steel, epoxy coated bars exhibited slower and less pronounced impedance variations, indicating greater resistance to corrosion and chloride penetration. These results validate the EMI technique as an effective and reliable method for early detection of chloride induced corrosion, offering valuable insights for real time SHM. The study underscores the superior corrosion resistance of epoxy coated bars and their potential to enhance the lifespan of RC structures. Additionally, it highlights the importance of innovative SHM techniques in infrastructure management, contributing to more effective maintenance strategies.

This study investigates the effectiveness of high shear dispersion (HSD) as a scalable and energy-efficient technique for incorporating nano-alumina (NA) into conventional M40-grade concrete, addressing a key limitation of nanoparticle agglomeration commonly reported in nano-modified cementitious systems. Nano-alumina was incorporated at dosages of 0.5%, 1.0%, and 1.5% by weight of cement, and its influence on mechanical performance, durability, microstructural refinement, and statistical reliability was systematically evaluated. Results demonstrate that HSD enables uniform NA dispersion in the range of 10–30 nm, leading to pronounced improvements in concrete performance. At 28 days, the compressive, split tensile, and flexural strengths increased by 26.99%, 37.5%, and 48.14%, respectively, for concrete containing 1.5% NA, compared to the control mix. Long-term curing further enhanced performance, with compressive strength reaching 74.04 MPa at 180 days. Durability assessments revealed improved resistance to chemical attack (NaCl, HCl, and H2SO4), freeze–thaw cycles, and elevated temperatures up to 400 °C, attributed to refined pore structure and reduced permeability. Microstructural analysis using SEM–EDX confirmed significant matrix densification, reduction in average void size by approximately 65%, narrowing of the interfacial transition zone, and the formation of secondary calcium–alumina–silicate–hydrate (C–A–S–H) gel. In addition, multivariable regression and Weibull statistical analyses demonstrated enhanced strength predictability and reduced variability with increasing NA dosage. Overall, this study establishes high shear dispersion as a practical and field-compatible alternative to ultrasonication, enabling reliable nano-alumina integration for the development of high-performance and durable concrete systems.

The primary objective of this study is to compare slab track systems and traditional ballasted track systems for high-speed rail (HSR) applications. The comparison focuses on design characteristics, life-cycle cost (LCC), maintenance requirements, structural performance, and environmental impacts. The goal is to evaluate suitability and long-term benefits of slab tracks in contrast to ballasted tracks, particularly in the context of growing HSR demands. The study is based on a comprehensive literature review, covering theoretical analyses, experimental investigations, and numerical simulations related to high-speed slab tracks. It includes comparative assessments of life-cycle cost, structural behavior, and maintenance strategies for both systems. Additionally, real-world case studies from HSR projects globally, with a special emphasis on India, are examined to identify trends, practical challenges, and best practices. The findings reveal that slab track systems, although requiring higher initial investments, offer significant advantages in terms of durability, structural robustness, and reduced maintenance needs. Numerical simulations demonstrate that slab tracks possess superior load-bearing capacity and better stability under dynamic HSR loads compared to ballasted tracks. Environmentally, slab tracks contribute to reduced noise and vibration levels, supporting sustainability goals. Life-cycle cost analysis confirms their economic efficiency over the operational lifespan. Slab track systems outperform traditional ballasted tracks in high-speed rail applications by offering improved performance, enhanced safety, and long-term cost-effectiveness. Their environmental benefits and low maintenance requirements make them strategic choice for future rail infrastructure. The study recommends adopting advanced slab track technologies in upcoming HSR projects and suggests future research should focus on optimizing construction materials, refining installation techniques, and strengthening performance monitoring systems.

The preservation of heritage structures has been a critical task globally, but using repairs without determining their compatibility with the existing materials causes the structures to deteriorate. Therefore, the prime objective of this study is to assess the bonding performance of old mortar prevalent in Indian historical structures with lime sand mortar and cement sand mortar as repair materials. Lime surkhi, lime sand, mud sand, mud surkhi, cement sand and cement surkhi mortar have been selected as substrates to assess their bonding compatibility with lime sand and cement sand mortar. The composite specimens have been tested to evaluate their performance under shear and tension by split, bi-surface and slant shear strength tests. The results suggest that the slant shear strength test and bi-surface strength test are suitable tests for assessing the compatibility of the lime surkhi, lime sand, mud sand, mud surkhi, cement sand and cement surkhi mortars with lime sand and cement sand repair mortars. The materials exhibiting adhesion repair are suitable for repair purposes. It is also inferred from the present study that the repairs should be performed by preparing the surface so that the substrate interface forms a 30° angle with the repair interface for a stronger bond. The experimental findings are validated with numerical simulations using Ansys software, and strong coherence is established between the experimental and simulation results.

This study develops a reusable non-bonded piezoceramic sensor (NBPS) system for split-tensile structural health monitoring of steel fibre concrete structures. The research addresses critical limitations in conventional destructive testing methodologies by integrating electromechanical impedance (EMI) signatures with deep learning regression for non-destructive tensile performance evaluation. The enhanced monitoring system evaluated both healthy and damaged steel fibre concrete cylinders at six volumetric dosages (0.25–1.5

The safety and comfort of high-speed train operations depend on effective and dependable track systems. A structural comparison of slab and ballasted track systems under static loading circumstances is presented in this work, with an emphasis on high-speed railway applications. The Mumbai–Ahmedabad high-speed rail corridor's actual geometry and material characteristics are included in the study via the use of finite element modelling in ANSYS. The primary structural responses—deflection, bending stress, and shear stress—were assessed. The results indicate that slab track systems perform better structurally than ballasted tracks, with a 45

Structural health monitoring (SHM) is vital for ensuring the longevity and safety of reinforced concrete structures, particularly in environments exposed to sulfates. This study investigates the application of the electro-mechanical impedance (EMI) technique to monitor sulfate attack in HYSD 500 grade steel bars, Epoxy-coated steel bars, and Glass fiber reinforced polymer (GFRP) bars. To simulate circumstances typical of sulfate-rich environments, such as those seen in industrial or marine settings, baseline impedance measurements were acquired using piezoelectric sensors fixated to the surface of these reinforcement bars before exposing them to sulfate solutions. Impedance data were recorded at regular intervals to detect changes in mechanical properties due to sulfate-induced degradation. Preliminary results show distinct differences in conductance signatures among the three types of reinforcement bars. Epoxy-coated steel bars exhibit delayed and less pronounced changes in conductance signatures, indicating better resistance to sulfate ingress and degradation compared to HYSD 500 grade steel bars. Additionally, GFRP bars demonstrated a unique degradation pattern, showcasing their non-metallic composition’s resistance to corrosion but susceptibility to material deterioration over prolonged sulfate exposure. This study confirms that the EMI technique is a sensitive and reliable method for early detection of sulfate attack, providing valuable data for real-time SHM. The findings highlight the superior sulfate resistance of epoxy-coated and GFRP bars, emphasizing their potential for extending the lifespan of reinforced concrete structures. This research contributes to improved maintenance strategies and underscores the importance of innovative SHM techniques in infrastructure management.

This research develops a novel non-destructive measurement approach integrating electro-mechanical impedance (EMI) technology with innovative reusable non-bonded surface piezoelectric sensors (NBPS) for steel fibre cement-based materials (SFCM). The measurement of SFCM structural health monitoring faces significant limitations due to reliance on destructive testing methods. Therefore, this experimental program can systematically provide damage assessment of SFCM specimens containing hooked-end steel fibres at six dosage levels (0.25, 0.5, 0.75, 1, 1.25, and 1.5 %) with aspect ratios of 55 and 65, evaluating both healthy and damaged states over 28 days. EMI signature analysis focused on resonance frequency shifts and peak conductance variations, with damage quantification achieved through statistical metrics including RMSD and MAPD. Results demonstrate that specimens with an aspect ratio of 65 consistently outperformed those with an aspect ratio of 55, achieving optimal compressive strength of 60.95 MPa at 0.75 % fibre content (47.5 % improvement). Machine learning frameworks accomplished outstanding compressive strength prediction (R2 = 0.99) with immediate convergence, developing EMI-based analysis. The validated EMI-NBPS system offers a transformative non-destructive solution for structural health monitoring, enabling immediate strength assessment and damage detection in fibre-reinforced cementitious materials for construction quality control and infrastructure monitoring applications. This paper will serve as a primary reference for non-bonded PZT in SFCM damage monitoring due to the crucial process of strength changes, focusing on the observation, calibration, and validation of selecting structural parameters, including equivalent stiffness, damping, and mass.

Corrosion of reinforcement is one of the primary causes of deterioration in reinforced concrete (RC) structures exposed to chloride-rich environments. Even though other reinforcement materials like epoxy-coated and glass fiber reinforced polymer (GFRP) rebars have been established to enhance durability, there are very few reliable monitoring methods that can help to assess deterioration in the various reinforcement systems. To address this, the Electro-Mechanical Impedance (EMI) technique with embedded piezoelectric sensor (EPS) was utilized in this research to measure the chloride-induced degradation of RC specimen with three types of reinforcement (High Yield Strength Deformed (HYSD) 500, epoxy-coated and GFRP bars) and three types of concrete systems (ordinary Portland cement (OPC), Portland pozzolana cement (PPC) and limestone calcined clay cement (LC³)). The specimens were subjected to accelerated chloride exposure using an impressed voltage setup in a 3.5% NaCl solution. EMI responses were evaluated using statistical damage indices, including root mean square deviation (RMSD) and mean absolute percentage deviation (MAPD), along with equivalent structural parameters derived from impedance. Results indicate significant variation in deterioration across RC combinations. HYSD 500 specimens exhibited the highest damage, with RMSD reaching 81.33% and stiffness reduction up to 64.10% in OPC systems. Epoxy-coated reinforcement showed reduced deterioration, with stiffness reduction between 17% and 52%, demonstrating the protective role of the coating. In contrast, GFRP specimens exhibited minimal stiffness variation (<5%), confirming the absence of electrochemical corrosion. Among the binders, LC³ systems consistently demonstrated delayed deterioration and lower damage indices compared to OPC and PPC systems. A combined durability framework using radar analysis and a Composite Performance Index (CPI) further confirmed the superior performance of LC³ based systems. The study demonstrates that EMI-based multi-parameter assessment provides an effective non-destructive approach for evaluating durability of RC systems under chloride exposure.

The increasing demand for sustainable construction materials has encouraged the utilization of industrial by-products as partial replacements for cement in concrete. This study investigates the performance of M40 grade concrete incorporating calcined clay (CC) and calcined lime sludge (CLS) as supplementary cementitious materials. Different concrete mixes were prepared by replacing cement with CC and CLS at proportions of 5%-20%. The fresh and hardened properties of concrete were evaluated through workability, compressive strength, split tensile strength, flexural strength, and water absorption tests at different curing ages. The results indicated that concrete workability decreased with increasing replacement levels due to the higher specific surface areas of CC and CLS. However, the mechanical properties improved at moderate replacement levels. The optimum mix (15% CC + 10% CLS) showed similar to 15%-20% higher compressive strength compared to the control at 90 days, with reduced water absorption. The mix containing 15% CC and 10% CLS exhibited the highest split tensile, and flexural strengths compared with the control mix, indicating a synergistic effect between the pozzolanic activity of CC and the calcium-rich composition of lime sludge. Beyond this replacement level, a reduction in strength and an increase in water absorption were observed. Response surface methodology effectively identified the optimum mix of 15% CC and 10% CLS, with a curing period of 90 days, demonstrating higher predictive capability for optimizing the mechanical and durability characteristics of concrete. This study demonstrates that the combined use of CC and CLS can enhance the mechanical performance of concrete while reducing cement consumption and promoting the sustainable utilization of industrial waste materials, supporting SDGs 9, 11, and 13.

This study presents a data-driven framework to optimize the mechanical and workability performance of geopolymer concrete (GPC) by refining key mix parameters liquid-to-binder ratio, NaOH molarity, SS/SH ratio, superplasticizer dosage, and curing temperature. Produced from industrial by-products such as fly ash and activated with alkaline solutions, GPC offers a sustainable alternative to cement-based concrete but lacks standardized mix design guidelines due to complex interactions among variables. A comprehensive dataset of 550 samples, comprising 300 literature data points and 250 experimental mixes, was developed to train and validate predictive models. The dataset covers a wide range of parameters: L/B ratio (0.24–0.8), fly ash content (250–530 kg/m3), coarse aggregates (654–1567 kg/m3), fine aggregates (318–817 kg/m3), NaOH molarity (8–16 M), SS/SH ratio (1.5–3.5), and curing temperature (27–100 °C). Experimental results identified optimal mix conditions: L/B ratio of 0.55, 1.5

This study aims to identify variables that influence the vibration-dampening characteristics of an elastic anti-vibration slab mat layer in railway slab tracks. Specifically, it investigates how the motion of vehicle over slab track, combined with stationary load, transforms into a dynamic load due to instability between the rail and wheel surfaces. The research question focuses on understanding how an additional anti-vibration slab mat layer installed beneath the concrete layer affects the overall vibration response of slab track system. There are two sections to the study. The first section provides an overview of current high-demand prefabricated concrete slab track systems for high-speed rail. The second section involves a detailed vibration response analysis, employing a parametric investigation using the finite element method (FEM) to evaluate the influence of elastic material slab mat layer on vibration response of precast slab track system. The findings from the vibration response analysis indicate that certain mechanical specifications of the anti-vibration mat significantly contribute to reducing the vibration response in slab track. These specifications include increased thickness, lower stiffness, train velocity, track stiffness, damping properties, and load variations have been analysed to evaluate their influence on system performance. This study offers valuable insights into design and application of slab mat layers, providing recommendations for their implementation in high-speed rail systems. The results demonstrate that optimizing thickness, stiffness, and damping ratio of anti-vibration mat can effectively mitigate vibrations, thereby enhancing overall functionality and efficiency of high-speed rail systems. Higher train speeds and axle loads significantly increase rail and slab accelerations, with slab responses being more sensitive to lighter loads. Assessing track performance is essential to ensure safety under high-speed and heavy-load conditions. Increasing slab mat thickness effectively reduces displacements, especially for slab displacements at higher foundation modulus values.

The cement industry accounts for nearly 8% of global CO2 emissions, underscoring the urgent need for eco-efficient construction materials that align with the Sustainable Development Goals (SDGs). This study explores the partial replacement of Ordinary Portland Cement with lime sludge (LS), a calcium-rich industrial by-product from paper manufacturing and metakaolin (MK), a reactive pozzolana derived from calcined clay, to develop sustainable concrete composites supporting the 3R principles (Reduce, Reuse, Recycle) SDGs 9 and 11. The research aimed to determine the optimal proportions of LS and MK for enhancing concrete performance while reducing cement consumption and overall energy demand. A total of 16 concrete mixes (M25 grade) were designed with varying LS (0%–15%) and MK (0%–15%) replacement levels. The mix containing 10% LS and 10% MK (L10M10) demonstrated superior performance, showing a 22.8% increase in 28-day compressive strength and a 25.8% improvement at 90 days compared with the control (L0M0). Flexural and tensile strengths improved by 13.2% and 12.5%, respectively. The density of L10M10 increased by over 10%, while water absorption decreased from 8% to 6.4% and acid-induced mass loss reduced from 10% to 8% after 12 weeks, indicating enhanced durability. Scanning electron microscopy analysis revealed a denser microstructure with refined C–S–H gel formation and minimal porosity, whereas energy dispersive spectroscopy confirmed favorable Ca/Si (1.8) and Si/Al (26) ratios promoting stability and strength. This approach demonstrates a 20%–25% potential energy saving during clinker production and encourages valorization of industrial by-products, reducing landfill waste.

With the progress in codal provisions for steel structure design, it has significantly reinforced the durability and flexibility in modern design. With the introduction of new Indian Standard code for design and detailing for steel building, IS 18168:2023 has replaced the earlier provision mentioned in section 12 of IS 800:2007. This study emphasizes taking into consideration new clauses for design of steel building and compares these provisions through modelling different structural steel systems under seismic events. The structure analyzed on loading combination defined in new code as well as load combination outlined in IS1893:2016. The concept of capacity-protected elements is also introduced in this code which is explored in this study. The code mentions the limiting value for the slenderness ratio at the location of plastic hinge formation. For the current study, G+4 structure is being prepared which is situated in Earthquake Zone IV. ETABS 2019 version is used and results are compared on the parameter such as storey drift, maximum story displacement and base shear value of SMRF, SCBF &; EBF structural system. The beam-column strength ratio is defined in this code. The finding of this study reveals that SMRF system has the maximum storey drift in X direction but least in Y-direction. In all three structural system used in this study EBF structural system exhibit the highest base shear while SMRF system shows minimum value of base shear.

Nearly 8% of carbon dioxide is emitted by the cement industry, which highlights the demand for alternatives which supports sustainable development. this study focuses on developing a sustainable concrete by the partial replacement of cement with calcium rich lime sludge (LS) and aluminosilicate material from calcinated kaolinite clay popularly known as Metakaolin (MK). The main aim is to formulate eco-friendly concrete composites that advance the 3R principles (Reduce, Reuse, Recycle) and align with sustainable development goals (SDGs) 9 and 11. 16 concrete mixes of M25 grade are prepared, varying LS and MK content from 0 to 15%, to evaluate the combined effect on workability, strength, and durability. Mechanical and durability tests were supported by microstructural (SEM) and elemental (EDS) analyses to assess matrix refinement and hydration properties. The mix with 10% LS and 10% MK delivered the better performance, attaining a 22.5% and 25.8% hike in 28- and 90-day compressive strength, respectively, compared to the control mix. The tensile and flexural strengths improved by 12.5 and 13.2%, respectively. M10L10 also exhibited a greater than 10% hike in density, water absorption (reduction from 8% to 6.4%), and lesser acid-induced weight loss (from 10 to 8%), reflecting chemical resistance and enhanced impermeability. The SEM results showed a compact microstructure dominated by CSH gel, while EDS indicated balanced Ca/Si (1.8) and Si/Al (26) ratios, denoting improved stability of gel. The synergistic reaction between MK and LS not only improved mechanical and durability parameters but also cut cement demand and reduced carbon dioxide emissions. The regression analysis effectively predicts behaviour of concrete and validates the efficiency of MK-LS blends as a sustainable, high-performance alternative to conventional cementitious materials (CCMs). Therefore, this dual-waste approach offers a 20-25% energy saving in clinker production and promotes industrial waste valorisation, contributing to a circular, low-carbon, and scalable pathway for sustainable concrete development.

Nanotechnology has emerged as a transformative approach to enhancing the concrete properties. This research examines the impact of nano-titanium dioxide (NT) on the concrete properties. NT was incorporated in varying dosages (0.5%, 1%, and 1.5% by weight of the cement) to assess its impact on strength, toughness, and resilience. The results demonstrated a significant enhancement in mechanical properties, with a peak compressive strength of 65.20 ± 1.03 MPa, a split tensile strength of 3.44 ± 0.17 MPa, and a flexural strength of 9.5 ± 0.47 MPa at a 1.5% NT dosage after 28 days of curing. Furthermore, the long-term performance was notable, as the compressive strength further increased to 75.25 ± 1.10 MPa at 180 days, confirming the sustained strength-gain potential of NT-incorporated concrete. Also, durability assessments were conducted under aggressive conditions, including exposure to 4% NaCl, HCl, and H2SO4 for 90 days. Additional tests, including rapid chloride penetrability test (RCPT), surface resistivity, freeze-thaw resistance, and accelerated carbonation, were conducted to assess long-term durability along with its economic feasibility. The NT-incorporated concrete demonstrated enhanced resistance to chloride ingress, acid attack, and elevated temperatures (200-600 °C), with improved modulus of elasticity and fire resistance. Furthermore, durability assessments revealed a noteworthy contrast, i.e., while resistivity tests classified NT-incorporated concretes as having 'very low' chloride penetrability, RCPT values remained in the 'moderate' category. This divergence underscores the need for multiple durability indices in evaluating nano-concretes. Microstructural analyses using scanning electron microscopy confirmed the densification effect of NT, leading to a refined pore structure and improved bond efficiency within the cementitious matrix. Moreover, economic analysis confirms the economic viability of nano-titanium concrete, demonstrating significant long-term savings through service life extension despite higher initial investment. This research highlights the potential of NT in developing high-performance, durable concrete, reinforcing the importance of nanotechnology in construction industry.

The primary focus of this work is to evaluate dynamic responses of precast slab track systems under the influence of high-speed trains. This study is crucial for India, as it addresses the challenges of implementing advanced rail systems to meet growing transportation demands while ensuring safety, efficiency, and sustainability. A computational methodology based on moving element method is utilised, incorporating moving coordinate system in order to model vehicle-track coupling system in terms of dynamically behaviour. The vehicle is represented as 26-degree-of-freedom multi-body system, with nonlinear Hertz contact theory governing wheel-rail interactions. The slab track is demonstrated as three-layer Euler–Bernoulli beam structure, considering nonlinear friction behavior of rail pads. The study solves nonlinear dynamic equations of motion using Newmark integration method. The results indicate that moving element method provides accurate predictions of dynamic responses, with outcomes aligning closely with traditional finite element methods. Parametric studies highlight effects of track irregularities, train speed, and track material properties on system's performance. For optimal design, stiffness of rail pad, subgrade, and cement asphalt mortar layer are identified as critical parameters. This study concludes that moving element method is an efficient and reliable computational tool for analyzing dynamic interactions in high-speed rail systems, offering insights into optimizing slab track designs. The model assumes linear elastic behavior for structural materials, such as concrete and mortar, which may not fully capture nonlinearities under extreme loading conditions.