Rsif Scholars' Publicationshttps://repository.rsif-paset.org/xmlui/handle/123456789/32024-03-29T15:29:27Z2024-03-29T15:29:27ZEffects of raw and different calcined bentonite on durability and mechanical properties of cement composite materialFode, Tsion AmsaluJande, Yusufu Abeid ChandeKivevele, Thomashttps://repository.rsif-paset.org/xmlui/handle/123456789/3882024-03-12T08:49:39Z2024-07-01T00:00:00ZEffects of raw and different calcined bentonite on durability and mechanical properties of cement composite material
Fode, Tsion Amsalu; Jande, Yusufu Abeid Chande; Kivevele, Thomas
Bentonite is a natural pozzolanic material mostly composed of SiO2 and employed in cementing materials for the reduction of cement consumption and CO2 emission besides improving performance of cement composite material by consuming portlandite to form extra C-S-H gel. So, many researchers studied on partial replacement of bentonite to improve concrete performance. However, bentonite mostly exists as a consolidated form that needs treatment for activation of pozzolanic reactivity to improve performance of cement composite materials. However, it is not well known how different replacement of raw and calcined bentonite affects performance of cementing materials in different hazardous environment. Hence, the present study identified the most influential replacement of bentonite, evaluating different calcined and raw bentonite in environments of acids, salt, and elevated temperature in addition to assessing the mechanical and physical properties of cement composite material. So, the results indicate that the employment of raw and calcined bentonite reduces the fresh bulk density, improves compressive strength, and Vicker hardness at 28 days, reduces the mass loss due to 56 days immersion in 5% HCl, 10% NaCl, and 5% HNO3 compared to the control mixture. Moreover, the employment of calcined bentonite at 800 °C significantly improved the durability and mechanical properties of cement composite materials compared to the control mixture. Specifically, replacing bentonite calcined at 800 °C for 3hs by 20% has the highest compressive strength than all samples after 28 and 56 days. Besides these, the study reveals that the corrosion potential of steel bars embedded in the mortar is reduced as the proportion of raw and different calcined bentonite increases. Generally, the employment of calcined bentonite is very beneficial to get improved performance on mechanical and durability properties of cement composite materials.
Journal article
2024-07-01T00:00:00ZEffect of Natural Pozzolana on Physical and Mechanical Properties of ConcreteFode, Tsion AmsaluJande, Yusufu Abeid ChandeKivevele, Thomashttps://repository.rsif-paset.org/xmlui/handle/123456789/3872024-03-11T18:41:07Z2024-02-13T00:00:00ZEffect of Natural Pozzolana on Physical and Mechanical Properties of Concrete
Fode, Tsion Amsalu; Jande, Yusufu Abeid Chande; Kivevele, Thomas
Construction industries are rapidly growing, sacking high amounts of concrete which has a highly dense microstructure with excellent mechanical properties, more durable, and highly eco-friendly materials. Hence, many of the researchers are interested in solving this problem with replacing concrete by natural pozzolana (NP) which is a supplementary cementitious material mostly from volcanic sources having much active silica content that can improve the durability and mechanical properties of concrete. However, it is not well-known which common optimum replacement range can give the most desirable concrete properties. So, the present study sought to review the effects of replacing NP from volcanic sources on the durability, physical, mechanical, and microstructural properties of concrete, also, to identify the most common dose of a positive effect as a replacement in concrete. The review shows that many of NP used by different literature from different places satisfy ASTM replacement standard in concrete, especially, based on its chemical compositions. Also, the review observed that employing NP in concrete significantly improves concrete workability, lengthens setting time, and reduces bulk density, porosity, water absorption, and chloride ion migration by making denser concrete microstructure. In general, adding 5%–20% of NP in concrete significantly improves compressive strength, split tensile strength, and flexural strength. Specifically, most of the studies found 15% replacement of NP having volcanic sources can give optimum strength. Besides these, most of the studies indicated that the improvement of the strength was more visible at the concrete age of 7–28 days.
Journal article
2024-02-13T00:00:00ZTheoretical investigation of electronic, energetic, and mechanical properties of polyvinyl alcohol/cellulose composite hydrogel electrolyteOffia-Kalu, Nkechi ElizabethNwanonenyi, Simeon ChukwudozieAbdulhakeem, BelloDzade, Nelson YawOnwalu, Peter Azikiwehttps://repository.rsif-paset.org/xmlui/handle/123456789/3862024-03-11T18:13:49Z2024-03-01T00:00:00ZTheoretical investigation of electronic, energetic, and mechanical properties of polyvinyl alcohol/cellulose composite hydrogel electrolyte
Offia-Kalu, Nkechi Elizabeth; Nwanonenyi, Simeon Chukwudozie; Abdulhakeem, Bello; Dzade, Nelson Yaw; Onwalu, Peter Azikiwe
Hydrogels are a new class of electrolytic materials employed in zinc-air batteries due to their significant on the battery's performance. However, the effectiveness of electrolytic hydrogel is affected by factors such as water content, temperature, additives, etc. Using DMol3 and molecular dynamics modeling techniques, this research aimed at investigating the electronic properties, effect of water content, and temperature on the binding energy, cohesive energy, and the mechanical properties of polyvinyl alcohol/cellulose-based composite hydrogel at the molecular level. The electronic optimized structures of the polymeric materials and parameters such as frontier molecular orbitals, band gap and electron density were analyzed. The results revealed that the binding energies of hydrogel polymer composite increased as the number of water molecules in the composite increased up to 60 % after which the binding energy decreased. In addition, the temperature increase led to a decrease in the binding energy of the composite. The cohesive energy density of the composite was highest at 40 % water content while higher temperatures decreased the cohesive energy density of the hydrogel. As the number of water molecules increased from 29 to 256, the tensile modulus increased from 0.707 × 10−3 to 2.821 × 10−3 Gpa; while the bulk modulus (K) increased in the order of K 40 > 50 > 30 > 20 > 10 respectively. These results serve as a theoretical enlightenment and a guide for experimental works in the field of energy conversion and storage devices.
Journal article full text: https://doi.org/10.1016/j.jmgm.2023.108667
2024-03-01T00:00:00ZElectrosorption of paraquat pesticide on activated carbon modified by aluminium oxide (Al2O3) with capacitive deionizationAlfredy, TusekileElisadiki, JoyceDahbi, MouadKing'ondu, Cecil K.Jande, Yusufu Abeid Chandehttps://repository.rsif-paset.org/xmlui/handle/123456789/3852024-03-11T18:13:22Z2024-03-01T00:00:00ZElectrosorption of paraquat pesticide on activated carbon modified by aluminium oxide (Al2O3) with capacitive deionization
Alfredy, Tusekile; Elisadiki, Joyce; Dahbi, Mouad; King'ondu, Cecil K.; Jande, Yusufu Abeid Chande
Composite electrode materials for removing paraquat from contaminated water were synthesized by loading aluminium oxide (Al2O3) onto activated carbon (AC) via co-precipitation method. The composite properties were investigated by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and energy-dispersive X-ray spectroscopy. Capacitive deionization batch experiments compared the electrosorption of paraquat herbicide by the composite electrode and the pristine activated carbon. The performance of the composite electrodes showed that the removal efficiency and adsorption capacity depend on the aluminium oxide loading, applied potential, flow rate, and charging time. At 1.2 V, a flow rate of 15 mL/min, a charging time of 3 h and 20 mg/L PQ initial concentration, the composite electrode (AC/Al2O3-1:1) demonstrated a removal efficiency, electrosorption capacity, and energy consumption of 95.5 %, 1.27 mg/g, and 0.055 kWh/m3, respectively, compared to 62 %, 0.83 mg/g, and 0.11 kWh/m3 for the unmodified AC. The presences of other ions/pollutants were found to have negligible interference on PQ pesticide removal as the removal efficiency and electrosorption capacity of the AC/Al2O3-1:1 composite in both artificial (95.5 %, 1.27 mg/g) and natural water (87.5 % 1.17 mg/g). The study confirmed that composite electrode can reused several times, as there was no significant decrease in its regeneration efficiency even after multiple cycles.
Journal article full text: https://doi.org/10.1016/j.desal.2023.117116
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