Indian Journal of Engineering and Materials Sciences (IJEMS)

Effect of quick lime addition for improving compressive strength of fly ash based (cement free) geopolymer concrete

2024-11-07T18:07:25+0530

In this current investigation, a comprehensive exploration has been undertaken to advance the development of “Class F” fly ash- based Geopolymeric mortar and concrete, utilizing fly ash sourced from the Satpura Thermal Power station in Sarni, District Betul, Madhya Pradesh, India. The study systematically investigates the Influence of Quick Lime Addition in the formulation of Fly Ash-based Geopolymeric Mortar and Concrete, with a particular focus on enhancing Compressive Strength within the constraints of Ambient Atmosphere conditions. The Geopolymeric binder is meticulously crafted using sodium hydroxide and sodium silicate as alkaline activators. Systematic variations of Quick Lime dosages (ranging from 0% to 10% by weight of fly ash) were introduced, and the ensuing specimens underwent scrutiny for standard consistency and setting time under ambient temperature curing. The outcomes underscore a discernible trend wherein the judicious addition of 7 to 9 wt.% calcium oxide (Quick Lime) to the fly ash matrix precipitates a noteworthy reduction in setting time at room temperature, concurrently manifesting a substantial enhancement in compressive strength for Geopolymeric mortar and concrete formulations. The elucidation of the binder's microstructural phases and their chemical characteristics was pursued through rigorous analytical methodologies, encompassing X-ray fluorescence (XRF), X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Field Emission Scanning Electron Microscopy (FE-SEM). Cost Analysis was also done for 1m3 concrete, the comparison between Conventional Concrete (M25) and fly ash based Geopolymer concrete.

Seismic acceleration amplification factor under fixed and pin supported RC frame building

2025-08-07T11:51:59+0530

Assessing non-structural elements' vulnerability to acceleration relies on peak horizontal floor acceleration. Given the dynamic nature of structures, estimates for forces acting on elements like mechanical, electrical, or architectural components are crucial. The amplification factor for these non-structural components is affected not just by building height but also by the structural support conditions. This study examined five distinct building models spanning 2, 4, 6, 8, and 10 stories. These models were analysed using the linear time history method under various near-field Chi-chi earthquake scenarios (ranging from 0.01g to 0.067g, 0.067g to 0.2g, and 0.2g to 0.32g). This analysis aimed to determine the acceleration amplification factor (Ω), representing the ratio of peak floor acceleration to ground acceleration, for both fixed and pinned support conditions. A disparity emerged after comparing the actual acceleration amplification values under fixed and pinned support conditions with those from previous models. While some models performed adequately under fixed support conditions, others yielded accurate results under pinned support conditions. Consequently, there's no singular formula capable of effectively accommodating both support conditions across the varying ranges of ground motion.

Enhanced mechanical and durability performance of dry mix concrete made with silica-coated aggregates

2025-02-05T10:27:06+0530

This research work has focused on enhancing the mechanical and durability properties of M40 grade concrete by replacing natural granite coarse aggregates with silica-coated granite aggregates. The mix has been further improved by changing the order of mixing ingredients and by using a mechanically modifying binder. Improvement in the fresh state properties of all the mixes has been observed due to the formation of a lubricating layer over the aggregates as a result of the slurry coating compared to control concrete. Around 48% increase in 28 days’ compressive strength, 47% enhancement in flexural strength and 36% in tensile strength have been observed with the modified formulations. Furthermore, the enhanced formulation lowers the chloride penetration by 20% and water penetration by 80%. The dense interfacial transition zone of scanning electron microscopic images has shown that the use of silica-coated aggregates, along with mechanically modifying the binder and changing the order of mixing, has imparted superior mechanical and durability properties to the concrete compared to conventional methods.

Fully coupled analysis of a floating offshore wind turbine under wind and wave loading

2024-08-29T11:11:37+0530

Floating Offshore Wind Turbines (FOWTs) have been exposed to a multi-hazard scenario of wind and wave conditions, which have acted simultaneously. To assess their combined effect on the FOWT and to ensure the safety and stability of the supporting structure, numerous complex loading conditions, such as wind-induced aerodynamic loads, wave-induced hydrodynamic loads, and the dynamics of the supporting structure, have been considered. In this study, a comprehensive time-domain analysis of the NREL 5 MW Reference Wind Turbine (RWT) supported on the OC4 DeepCwind semi-submersible has been carried out under both operating and parked conditions using the aero-hydroservo-elastic tool OpenFAST. The operating condition of the FOWT has included simulations at various wind speeds from cut-in to cut-out wind speed, with co-existing wave parameters for each wind speed. Based on the fully coupled analysis of the FOWT under simultaneously acting wind and wave conditions, the principal parameters required for the structural design of the rotor and supporting structure, such as blade-root moments and tower fore-aft/overturning moments, have been presented, alongside the key aspects of environment-structure interactions.

Design, development and field evaluation of a tractor-operated ginger planter

2024-11-25T22:20:55+0530

Ginger rhizome planting has been a challenge for farmers in India due to the lack of suitable machinery. Farmers continue to rely on traditional planting methods, which are time-consuming, labour-intensive, and associated with significant human drudgery and a high demand for manual labour. Major ginger-growing states often experience labour shortages during the sowing season. To address this challenge, a tractor-operated ginger planter was developed and tested at ICAR-Central Institute of Agricultural Engineering, Bhopal, for planting ginger seed rhizomes. The field tests revealed that cup size, speed, and ginger seed grades significantly influenced the performance of the developed planter. As the cup size increased, the percentage of multiples increased, while the percentage of missed seeds decreased. The highest quality of feed index was observed at the speed of 2 km/h with cup size A₂for graded seeds. The developed ginger rhizome planter enables precise planting of seed rhizomes, with an effective field capacity of 0.25 ha/h and required 50 man-h/ha. The labour requirement is reduced by 76% (11 times) compared to conventional planting methods. Furthermore, the developed planter cuts operational costs by 40% and significantly reduces the human drudgery involved in ginger planting operations.

Development of a portable digital colour meter for lignocellulosic fibers

2025-04-15T14:52:15+0530

The present study has intended to develop a battery-powered portable digital colour meter that works on the principle of photo reflectance to measure the whitness value of lignocellulosic fibres. The developed instrument has comprised light-emitting diodes, photodiodes, capacitor, display, microcontroller, and battery with booster. Light-emitting diodes (LEDs) of 5 mm have been used to provide uniform illumination and BPW34 silicon PIN photodiode sensors provided to measure the reflected light from the fibre, which intern produces voltage, which has then calibrated for color values. The calibration has revealed that there is a high degree of correlation between output voltages for given whitness value with R2 value more than 0.97. The developed instrument has been tested for three fibres i.e., jute, mesta and kenaf. The results have been compared with commercially available colour measuring instruments like colour and lustre meter and spectrophotometer. A comparative analysis has shown that the readings from the developed portable instrument are not significantly different (P > 0.05) from those of commercial instruments. Further, instrument measurements are repeatable and reproducible in nature. The device is battery-powered, with a charge lasting up to two days. The instrument can be used to measure the color of other fibers as well.

Effect of radial jets in exhaust system of spark ignition engine – Exergy analysis

2025-04-15T12:21:00+0530

This research has examined the effect of radial air injectors on the theoretical exergy of an exhaust system in a Spark Ignition (SI) engine. The radial air injectors have been installed in three different positions along the silencer’s bend pipe. Exergy analysis has determined the amount of irreversibility in a process, and its quality, associated with the thermodynamic efficiency of work output. The results of the study have indicated that system efficiency has increased when using radial air injectors. The measurement of exergy destruction with 8 radial jets present has been 0.1679 kWh. With 16 jets, this value has risen to 0.2019 kWh and has increased further to 0.23 kWh with 24 jets. The results of the experiments have been analyzed, and it can be concluded that increasing the quantity of radial jets has had an effect on a system’s exergy performance. These results have provided evidence for the advantage of employing radial air injectors in exhaust systems of SI engines to make them more efficient and to decrease their negative environmental effects.

Electrical discharge machining of EN-40B high carbon alloy steel: Investigation of recast layer and multi-performance optimization

2025-03-06T22:16:20+0530

This study has investigated the machinability of EN-40 high-carbon alloy steel in electrical discharge machining (EDM) by analysing the recast layer morphology. Taguchi’s L16 design and the desirability function approach (DFA) with a simple optimization algorithm (SOPTA) have been used to optimize pulse on time (Ton), pulse off time (Toff), low voltage current(LV), and high voltage current (HV). Performance metrics have included rate of material removal (RMR), tool wear rate (TWR), and surface roughness (Ra). The SOPTA algorithm using MATLAB 22a has determined the optimal settings (LV = 25A, HV = 2A, Ton = 40 μs, Toff = 25 μs) with a composite desirability of 0.5784. A confirmatory test has verified the optimal setting and compared it with the initial setting. The experimental results have shown that EDM performance has been significantly enhanced by the proposed method, with RMR, TWR, and Ra having improved by 66.32%, 70.36%, and 55.64%, respectively.

Analysis of motor-battery combinations in EV system

2025-06-27T12:03:45+0530

Electric vehicles (EVs) have appeared as a potential option, giving zero emissions and a cleaner means of transportation. However, as the adoption of EVs has increased, the selection of the right motor and battery combination has become ever more important. This study has examined the performance of Brushless DC (BLDC), Induction Motor (IM), and Permanent Magnet Synchronous Motor (PMSM) for electric vehicle traction applications when powered by lithium-ion batteries. Because of its precision, quick dynamic response, and simplicity in attaining appropriate speed and torque control, the Field-Oriented Control (FOC) technique with PI controller has been used in this work. The simulation model and results have been carried out and compared by using MATLAB Software.

Hydrogel bonding meets pozzolanic reaction: A dual approach to soil stabilization

2024-11-12T19:07:39+0530

The present paper has addressed the development of the guar gum (GG) biopolymer and fly ash (FA) in soil stabilization with the objective of improving the geotechnical properties of weak soils. Unconfined compressive strength (UCS) and california bearing ratio (CBR) tests have been used to evaluate the performance of soils with varying proportions of GG and FA during different curing periods in the laboratory. The UCS results have indicated that the maximum response has been observed with 2% GG and 5% FA, where the UCS has risen considerably from 83.15 kPa in untreated soil to 356.11 kPa after 28 days of curing. Similarly, the CBR tests conducted under unsoaked conditions have shown an increase from 6.34 in untreated soil to 12.32 with the same 2% GG and 5% FA mix. The soaked CBR values have also improved, reaching 7.67% compared to 4.72% in untreated soil. The findings have demonstrated that soil strength has been significantly enhanced with curing time, with the most notable improvements occurring within the first seven days and continuing up to 28 days as a result of pozzolanic reactions. These outcomes have suggested that the integration of GG and FA has represented a cost-effective and environmentally friendly stabilization technique, offering enhanced compressive and load-bearing capacity, particularly in problematic soil conditions, and serving as a sustainable substitute for conventional chemical stabilizers such
as cement and lime.