This study investigated the possibility of developing self-compacting concrete (SCC) utilising silicomanganese fume (SMF), an industrial waste material. SCC was produced by replacing cement with 10, 20, 30, 40, 50, 60, 70, 80 and 90% SMF. First, an assessment of the fresh properties of 10 SCC mixtures was carried out, and then mixtures satisfying the fresh requirements were selected for further evaluation. Plastic shrinkage and setting time of the fresh SMF-SCC mixtures were measured, and thereafter the mechanical properties and drying shrinkage were evaluated. The incorporation of SMF increased the dosage of superplasticizer required for a certain flow, but it enhanced the filling ability and passing ability of SCC. In addition, the incorporation of SMF increased the plastic and drying shrinkage, as well as initial and final setting times. Although there was an improvement in mechanical properties of SCC mixtures containing 10 and 20% SMF, increasing the quantity of SMF beyond 20% negatively affected the mechanical properties. Furthermore, the use of SMF decreased the cost of SCC by 7–42% and the CO2 emission decreased by 10–68%.
Laser-induced breakdown spectroscopy (LIBS) is a powerful technique for elemental detection across various domains, including engineering, science, and med
This paper describes a study on finite element modeling (FEM) carried out on the ABAQUS platform for the prediction of flexural strength of corrosion-damaged reinforced concrete (RC) beams strengthened using layers of ultra-high-performance concrete (UHPC). Considering different combinations of the degree of reinforcement corrosion and thickness and configuration of UHPC layers, a total of twenty-two corroded, un-strengthened, and strengthened RC beam specimens were tested to record their flexural behavior. Following the flexural testing, the FEM was carried out considering the degradation in the diameter and the yielding strength of the corroded reinforcing bars. The cohesive surface bonding approach was used to simulate the interfacial bond stress slip between the corroded bars and surrounding concrete. The results of the FEM were validated using the experimental test results of the respective beam specimens. The FEM results (including crack pattern, flexural strength, stiffness, and linear and nonlinear behavior of the strengthened RC beams) were found to be in close agreement with the corresponding experimental test results. This indicates that the proposed FEMs can capture the flexural behavior of the corroded RC beams strengthened using layers of UHPC with high accuracy. Furthermore, a parametric study was carried out using the validated FEMs to investigate the effects of varying the compressive strength and thickness of UHPC layers on the flexural strength of the corroded strengthened RC beams.
The corrosion of reinforcing steel in concrete has been reported as one of the main durability problems of reinforced concrete (RC) structures exposed to chloride, carbonation or both. To investigate the structural performances of RC structures subjected to corrosive exposure, the corrosion of rebars embedded in concrete is accelerated to induce a targeted degree of reinforcement corrosion in a short time duration. Several earlier researchers have attempted to develop a setup to induce the accelerated corrosion of steel bars in concrete structures. However, the induced corrosion has not been simulative of the naturally occurring corrosion of steel in concrete, causing a lack of accuracy in the test results. In this study, an attempt was made to develop a novel approach that could be utilized to induce required degrees of reinforcement corrosion following a natural pattern. To demonstrate the efficacy of the proposed setup and procedure of introducing uniform reinforcement corrosion, RC beam specimens were designed, cast, and corroded to three different corrosion levels. After inducing reinforcement corrosion, the beams were tested under flexural stress, and then the corroded bars were extracted to measure the mass loss due to corrosion. The visual inspection and gravimetric and flexural test results showed the capability of the proposed corrosion setup and procedure to induce the targeted uniform corrosion of steel bars, simulating a real-life scenario and facilitating the evaluation of the effect of reinforcement corrosion on the flexural performances of RC beams with very high accuracy.
The present work shows the plate's wave propagation behavior made of exponent-law-based functionally graded materials (E-FGM) supported by viscoelastic foundations. In extreme thermal environments, where the E-FGMs are considered highly effective, the temperature influences the composite plate's properties. Therefore, this present study aims to investigate the wave propagation of the E-FGM plates by considering the temperature-dependent effective properties as functions of the position across the thickness and the thermal increase. The governing equations of the E-FGM plate are obtained by employing a simple higher-order shear deformation theory (HSDT) and utilizing the Hamilton principle. An eigenvalue problem is formulated to determine the principal wave propagation frequency. The effects of viscoelastic parameters on E-FGM plates' phase velocities under uniform thermal changes are investigated in detail. The results indicate that introducing metal-ceramic mixtures in the plate would lower the phase velocity in the plate. Furthermore, increasing a uniform temperature in the plate would deteriorate the foundation and plates and, therefore, result in lower velocity and less stiffness.
The studies assessed whether aging waste carbonated water (WCW) from wet carbonation of recycled concrete powder (RCP) affects cement hydration and performance. WCW was produced using MgCl2 solutions of 0.1, 0.2, 0.4, and 0.8 M, with carbonation times of 30, 90, 180, and 300 minutes. It was reused as mixing water immediately after carbonation (t₀) or after four months of storage (t₄ₘ), while Portland cement was partially replaced with 10% non-carbonated RCP. Isothermal calorimetry (≥72 h) measured induction, peak behavior, and total heat release. Heatmap analysis revealed that aging reversed the response surface: the cumulative heat optimum shifted from 0.1 M–300 min (12,500) at t₀ to 0.4 M–300 min (12,999) at t₄ₘ, with increases at 0.4–0.8 M (+1,399 at 0.4 M–300 min) and consistent decreases at 0.2 M (to −992 at 300 min). Therefore, aged WCW enhanced mixtures with higher Mg and longer carbonation times but reduced hydration at lower Mg levels. These trends were interpreted as storage-driven changes in ion species, including precipitation of Mg-bearing phases, CO₂ re-equilibration, and altered chloride activity. Future research will evaluate the practical implications by creating UHPC mixes with 10–30% RCP using aged WCW for mechanical properties, supporting a circular-water strategy that lowers freshwater demand while maintaining performance.
This paper seeks to study and investigate the wave dispersion behavior in porous functionally graded (FG) carbon nanotube-reinforced composite (CNTRC) beams. The beams comprise four patterns of single-walled carbon nanotubes (SWCNTs) distributed in the polymer matrix. The mixture rule is used to estimate the CNTR beams’ material properties. Innovative to this study are three porosity models describing the porosity distributions within the matrix and a three-unknown integral higher-order shear deformation theory (HSDT) modeling analytically the CNTRC beams with a novel shape function expressing the distributions of shear stresses and strains. The equations of motion for CNTRC beams are derived based on Hamilton’s principle. The stiffness and mass matrices are formulated by a generalized solution of harmonic wave propagation to express the wave dispersion relations. Numerical comparisons with previously published works verify the applicability of this mathematical model. The paper studies the effects of CNTs patterns through the polymer matrix, porosity models, and volume fractions of the porosity and CNTs. Based on the analytical results, augmenting the porosity and CNTs volume fractions leads to faster phase and group velocities. Furthermore, the impact of CNTs volume fractions, porosity models, and porosity volume fractions becomes more pronounced as the wavenumber increases.
The use of concrete-filled stainless steel tubular (CFSST) members is relatively innovative and new. CFSST columns can be used for bridge piers, multi-story buildings and other supporting structures. However, a common mode of failure with these type of tubular composite columns is inelastic outward local buckling occurring at the column ends. Therefore, this paper presents the results of experimental, numerical and analytical investigations into the behavior of circular CFSST columns strengthened by carbon fiber reinforced polymer (CFRP) wrap and subjected to axial compression loading. The experimental investigation comprised three series of tests. The main variables tested were the diameter to thickness ratio of the stainless steel tube and the thickness of the CFRP wrap. 3D finite element models (FEMs) were developed for CFRP-wrapped CFSST columns using the ABAQUS software and were validated with experimental results. An extensive parametric study was carried out by using the validated FEMs. It was shown from the experimental and FEMs results that CFRP jacketing was highly effective in improving the axial load carrying capacity and axial shortening capacity of the CFSST columns. Finally, an analytical model based on the FE parametric study results was proposed to predict the axial load carrying capacity of the CFRP-wrapped CFSST columns.
