Experimental Investigation and Comparative Analysis of Aluminium Hybrid Metal Matrix Composites Reinforced with Silicon Nitride, Eggshell and Magnesium.

In today's scenario, composite materials play a vital role in automobile, aerospace, and defence sectors because of their higher strength, light weight and other mechanical properties. Aluminium alloy Al6082 is a medium strength alloy with good corrosion resistance properties; hence, it is used for high-stress applications, bridges, cranes, etc. The present work focuses on comparing the mechanical properties of Al6082 and Al6082 with the addition of silicon nitride, magnesium, and bio waste of eggshells. Samples of Al6082 reinforced with 2% of silicon nitride (Si3N4), 5% of eggshell, and 1% magnesium reinforcements were prepared using the crucible casting process. Mechanical properties were evaluated through hardness test, tensile test and compressive tests, which varied with the additives of reinforcement materials. The results showed that the reinforced materials could increase mechanical properties. Further, it will be analysed by the machining parameters involved through the CNC turning process. Analysis of variance from optimisation technique shows a noteworthy increment of material removal rate (MRR) and significant decrement in surface roughness (Ra) and machining time compared to standard aluminium. Additionally, the analysis of mechanical testing has been predicted with the outcomes of stresses and displacements using the ANSYS platform.

Flexural Performance and Microstructural Studies of Trough-Shaped Geopolymer Ferrocement Panels.

Geopolymer mortar is the best solution as an alternative to cement mortar in civil engineering. This paper deals with the effect of geopolymer mortar on the strength and microstructural properties under ambient curing conditions. In this research, geopolymer mortars were prepared with fly ash and steel slag (in the ratio 1:2.0, 1:2.5 and 1:3.0) as precursors with NaOH and Na2SiO3 as activator solution solutions (in the ratios of 0.5, 0.75 and 1.0) with concentrations of NaOH as 8 M, 10 M, 12 M and 14 M to study the compressive strength behaviour. From the experimental results, it was observed that the geopolymer mortar mix with the ratio of fly ash and steel slag 1:2.5, 12 M NaOH solution and the ratio of NaOH and Na2SiO3 0.5 exhibits the maximum compressive strength results in the range of 55 MPa to 60 MPa. From the optimized results, ferrocement panels of size 1000 mm × 1000 mm × 50 mm were developed to study the flexural behaviour. The experimental results of the flexural strength were compared with the analytical results developed through ABAQUS software. It was observed that the Trough-shaped geopolymer ferrocement panel exhibits 56% higher value in its ultimate strength than the analytical work. In addition to the strength properties, microstructural analysis was carried out in the form of SEM, EDAX and XRD from the tested samples.

Experimental Investigation on the Potential Use of Magnetic Water as a Water Reducing Agent in High Strength Concrete.

High-strength concrete is designed for a self-weight reduction structure and exhibits higher resistance to compressive loads. This paper proposes a novel technique to enhance concrete's properties using Magnetic Field Treated Water (MFTW), describing the results of experimental studies to apprehend the fresh, hardened and microstructural behavior of concrete prepared with Magnetic Water (MW) using a permanent magnet with a field intensity of 0.9 Tesla. The novel scheme focuses on utilizing MW as a water-reducing agent instead of SP to improve the workability of fresh concrete with a 0.38 w/c ratio for achieving M40 grade concrete. Results show a 12% improvement in compressive strength and an 8.9% improvement in split tensile strength compared to normal water (NW) with 1% SP. At 30% cement volume reduction, Magnetic Water Concrete (MWC) performs better than Normal Water Concrete (NWC). Microstructure examination shows that a smaller Calcium Hydrate (CH) crystal is formed with MW and its mineral composition is observed through Energy Dispersive X-ray Analysis (EDAX).

Influence of Magnetic Water on Concrete Properties with Different Magnetic Field Exposure Times.

The characteristics of a concrete mix are purely dependent on the hydration of cement that is carried forward by using the water quality used in the mix. Several researchers have focused on incorporating pozzolanic or nanomaterials to improve the hydration mechanisms and impart high strength to concrete. A new technology has been introduced to improve the properties of concrete by magnetic-field-treated water (MFTW). Due to magnetization, water particles become charged and the molecules inside the water cluster decrease from 13 to 5 or 6, which eventually decreases the hardness of water, thus improving the strength of concrete when compared to the use of normal water (NW). In advanced construction techniques and practices, the application of Magnetic Water (MW) plays an important role in boosting physicochemical properties. This research work focused on evaluating the standards of water quality through physiochemical analysis, such as Electrical Conductivity (EC), Viscosity, pH, and Total Dissolved Solids (TDS) with the MW at different exposure periods (60 min (MW60), 45 min (MW45), 30 min (MW30), 15 min (MW15), and instant exposure (MWI)). Experiments were carried out to evaluate the fresh, hardened, and microstructural behavior of concrete made with magnetic water (MW) using a permanent magnet of PERMAG (N407) under a field intensity of 0.9 Tesla. In addition, optical properties such as X-ray Diffraction (XRD) and Ultraviolet (UV) absorption were considered for the MW60 mix to ensure water magnetization. Characterization methods such as Fourier Transform Infrared Spectroscopy (FT-IR), Thermogravimetric Analysis (TGA), and Scanning Electron Microscopy (SEM) were employed for NWC and MWC to quantify the hydrated products. From the results, it was observed that the magnetic effect on water characteristics showed significant improvement in the concrete properties with the increase in exposure duration. There were increments of 25.6% and 24.1% in workability and compressive strength, respectively, for the MW60 mix compared to normal water concrete (NWC).

Mechanical, Physico-Chemical and Morphological Characterization of Energy Optimised Furnace (EOF) Steel Slag as Coarse Aggregate in Concrete.

This research tests energy optimised furnace (EOF) steel slag as substitution for natural coarse aggregate in concrete. Steel slag's usefulness as a substitute for natural coarse aggregate in concrete is the primary goal of this research. According to IS:2386-1963, the characterization of EOF steel slag, as coarse, is done by examining the shape and size of a particle, mechanical properties, physical properties, soundness, and alkali-aggregate reactivity. Tests for detection of staining material in steel slag and hardness of inter-facial transition zone in hardened cement paste were also carried out. The chemical analysis of the steel slag reveals the stability of oxides present in the steel slag. Microstructural characterization by SEM (scanning electron microscope) analysis of steel slag aggregate was also employed to support the characterization and XRD analysis, and it was found that the EOF steel slag is crystalline. The digital image processing technique (DIP) is adopted to study the shape indices, circularity, sphericity, shape factor, and roundness of natural and EOF steel slag aggregate. According to the characterization and strength investigation, steel slag aggregate outperforms natural coarse aggregate.

Experimental Study on Self Compacting Fibrous Concrete Comprising Magnesium Sulphate Solution Treated Recycled Aggregates.

It appears that the awareness and intentions to use recycled concrete aggregate (RCA) in concrete are expanding over the globe. The production of self-compacting concrete (SCC) using RCA is an emerging field in the construction sector. However, the highly porous and absorptive nature of adhered mortar on RCA's surface leads to reduced concrete strength, which can be removed with the application of various techniques, such as acid treatment. This study investigated the effect of the partial replacement of silica fume by cement and natural aggregate (NA) by RCA with and without steel fibre. The used RCA was treated with magnesium sulphate solution. It was immersed in solutions with different concentrations of 10%, 15% and 20% and for different periods of 5, 10 and 15 days. Sixteen mixes were prepared, which were divided into six groups with or without 1% of steel fibre content. The fresh properties, compressive strength, split tensile strength and impact resistance were examined. The results revealed that the strengths of the mixes with 20% RCA were marginally better than those of the control mixes. The compressive strength and split tensile strength were reduced by 34% and 35% at 60% RCA content, respectively, as compared to the control mixes.