Mechanical Performance of Steel Fiber Reinforced Geopolymer Concrete
Maddula Rama Manikantha, M. Sophia
Page Numbers : 252-255
DOI : 10.36348/sjce.2022.v06i10.001
Concrete is used more than water worldwide. The need for Conventional concrete rises in tandem with the demand for concrete as a building material. According to estimates, cement production rose from 1.5 billion tons in 1995 to 4.5 billion tons in 2020. Finding a substitute for Cement concrete, whose production uses the most resources, is therefore inevitable. Researchers have been inspired to create an alternative binder paste to totally replace cement paste by the use of supplemental cementing ingredients such fly ash, silica fume, granulated blast furnace slag, and rice-husk ash. These inorganic amorphous binders will chemically react to form geo polymer concrete, a cutting-edge building material. We use additional cementitious materials in this that react with alkaline activators to create an Al-O-Si-O gel that has a comparable bonding strength to C-S-H gel. Because geopolymer concrete is already somewhat brittle, increasing its flexural and tensile strength is necessary. There are fibres included. In this study, the mechanical properties of geopolymer [M50] concrete with steel fibres were examined by curing it in an ambient condition.
Sept. 30, 2022
Polynomial Based Nonlinear Analysis of CCCS Thin Isotropic Rectangular Plate
Enem, J. I
Page Numbers : 235-243
DOI : 10.36348/sjce.2022.v06i09.002
This work is aimed at formulating a polynomial function for the nonlinear analysis of CCCS isotropic rectangular thin plate. The previous researchers used trigonometry function as their shape function on the decoupled Von Karman’s equations to obtain particular stress and displacement function respectively. Trigonometry function can only be used effectively for SSSS and CCCC plates; apart from these boundaries conditions its efficiency reduces. This present work hence used a polynomial function to formulate the approximate shape function for the CCCS plate. Direct variational calculus was used applied on Von Karman’s equations to obtain the general form of minimized total potential energy which serves as a platform for the determination of coefficient factor( Amplitude or coefficient of deflection). The numerical values of CCCS plate under unit load were obtained using Amplitude equation formulated. These values were obtained for various aspect ratio (ranging from 1 to 1.5 with an increment of 0.1). This work was compared with the previous work  and the percentage difference in the results are within the acceptable limit. This results indicate that the approach adopted by the present work is adequate, reliable and satisfactory for the analysis of CCCS rectangular plate.
Sept. 30, 2022
Development of Polynomial Based Program for Nonlinear Isotropic Rectangular Thin Plate
Enem, J. I
Page Numbers : 244-251
DOI : 10.36348/sjce.2022.v06i09.003
The work is aim at the development of a computer program for the nonlinear analysis of rectangular thin isotropic plate on Ritz method. Twelve boundary conditions were analyzed which include: SSSS, CCCC, CSCS, CSSS, CCSS, CCCS, CCFC, SSFS, CCFS, SCFC, CSFS, and SCFS. General expressions for displacement and stress functions for large deflection of isotropic thin rectangular plate under uniformly distributed transverse loading were obtained by direct integration of Von karman’s non-linear governing differential compatibility and equilibrium equations. Polynomial function as shape function was on the decoupled Von Karman’s equations to obtain particular stress and displacement functions respectively. Non-linear total potential Energy was formulated using Von Karman equilibrium equation and Ritz method was deployed in this formulation. A computer based program was developed using Matlab programming language to circumvent the challenges involved in solving the governing differential equations of thin rectangular plates. The developed program is capable of determining deflection and stresses at any point of the plate against the usual method of evaluating deflection at the center. The results obtained were compared with those of previous researchers The comparison made are only for SSSS, CCCC and CCCS plates. It was so because the remaining boundary conditions considered in this work have not been researched upon by previous researchers. From results obtained, the average percentage differences recorded for SSSS, CCCC, and CCCS plates for the present and previous studies are 4.01978%, 3.7646%, and 5.02% respectively. The percentage differences for the three plates compared are within acceptable limit of 0.05 or 5% level of significance in statistics. From the comparison made, it was obvious that an excellent agreement was observed in all cases thus indicating applicability and validity of the polynomial function and computer program for solving exact plate bending problems.
Original Research Article
Sept. 4, 2022
Modelling Studies of Retrofitted Anchorage System in Exterior Beam Column Joint by Supplementary Steel
Padmanabham, K, Rambabu, K, Sairam, K
Page Numbers : 215-234
DOI : 10.36348/sjce.2022.v06i09.001
A Nonlinear finite element based ABAQUS modeling studies were conducted to evaluate the performance of exterior Beam Column Joint (BCJ) under quasi-static test loads. Six integrated BCJ models representing different configurations of beam reinforcement anchored in joint are verified by using a novel retrofitting technique called "Post Installation of Supplementary Anchorage" (PISA) by using headed bar as supplementary steel. The configuration of beam reinforcement anchored in column are described by straight bar,90 degree bend ,180 degree hook (confirming to design code IS456:2000) and single head, double head bars (confirming to ACI 318-19, ACI 352R-02 ) and 90 degree long bend of ductile detailing (as per IS 13920-2016). Two series (A&B) of integrated joint specimens representing conventional (series-A) and retrofitted anchorage (series-B) systems are modeled and tested by using ABAQUS software. The test parameters considered are configuration of anchorage system and presence of supplementary anchorage. The test variables representing nonlinear performance of retrofitted joint system are Von Mises stress conditions, Principal tensile stress, Moment-Rotation, Degraded stiffness, Crack mechanics and Damage index. The results shows good improvement of post failure conditions of exterior beam-column joint such as relocation of plastic hinge mechanism and failure mechanics of retrofitted joint system. Also the results validated with experimental program on typical specimens casted and tested. This study imparts useful information on implicit retrofitting methods applied by external means in exterior beam-column joint. It also promotes performance based design principles with viable construction practice.
Original Research Article
Aug. 21, 2022
Compressive Strength and Optimization of Concrete Produced by Replacing Cement with Coconut Shell Ash (CSA) and Groundnut Shell Ash (GSA)
Sidi Yusuf Abdurrahman, Bunyamin Ayodeji Olawumi, Yakubu Idris, Ashiru Mode, Mohammed Abdulmumin Nda
Page Numbers : 207-214
DOI : 10.36348/sjce.2022.v06i08.002
The compressive strength and optimization of concrete produced by replacing cement with CSA and GSA was conducted in this study. The materials used were cement, water, fine aggregate, coarse aggregate, CSA, and GSA. The CSA and GSA replaced cement at 5, 10, 15, 20, and 25% in combination, with a total of seventy two (72) cubes cast, while the concrete compressive strength was determined after curing by complete immersion in water at 7, 14, 21, and 28 days. The modeling and optimization was done with the aid of design expert (version 13) software, while the Analysis of Variance (ANOVA) was done using SPSS (Statistical Package for Social Sciences) version 23 and adopting the Least Square Difference (LSD) method. Results from the findings showed that the CSA used in the study is a good reactive pozzolana, and the GSA is not a reactive pozzolana. Also, the increase in CSA and GSA content in concrete reduces its workability, and concrete compressive strength. However, cement replaced with 5%CSA-0%GSA gave the optimum 28 days compressive strength which is not statistically significantly from the control concrete and can be used to produce concrete of compressive strength close to the control. Further findings from the regression model showed that CSA-GSA concrete compressive strength significantly fits a linear model and can be used to predict the 7, 14, 21, and 28 days compressive strength of CSA-GSA concrete, while the optimized result showed that CSA and GSA replacement of cement at 3.29% and 4.45% respectively yielded an optimum compressive strength of approximately 22.31N/mm2.
Original Research Article
Aug. 11, 2022
Modeling and Optimization of Concrete Compressive Strength Produced by Replacing Natural Aggregate with Recycled Coarse and Recycled Asphalt Pavement Aggregates
Adamu Lawan, Aliyu Abubakar Abbas, Joshua Ochepo
Page Numbers : 197-206
DOI : 10.36348/sjce.2022.v06i08.001
The modeling and optimization of concrete compressive strength produced by replacing natural aggregate (NA) with recycled coarse aggregate (RCA) and recycled asphalt pavement (RAP) aggregates was investigated. The materials used were cement, water, fine aggregate, and coarse aggregate (NA, RCA, and RAP). The RCA and RAP replaced NA at 20, 40, 60, 80, and 100% separately, and in combination, with a total of two hundred and forty (240) cubes cast, while the concrete compressive strength was determined after curing by complete immersion in water at 3, 7, 14, 21, and 28 days. The modeling and optimization was done with the aid of design expert (version 13) software, while the Analysis of Variance (ANOVA) was done using SPSS (Statistical Package for Social Sciences) version 23 and adopting the Least Square Difference (LSD) method. Results from the findings showed that the optimum 28 days concrete compressive strength are concrete produced with 20%RAP, 40%(20%RAP +20%RCA), 60%(30%RAP + 30%RCA), and 80%(40%RAP + 40%RCA) replacements which are not significantly different from the control concrete, however, 40%(20%RAP +20%RCA) and 80%(40%RAP + 40%RCA) concrete had compressive strength higher than the control concrete. Also, the 3, 7, 21, and 28 days compressive strength can be predicted with quadratic model, while the 14 days strength can be predicted with 2-Factor Interaction (2FI) model. The optimization result showed that by replacing natural aggregate with 10.0% RAP and 50.0% RCA, the 28 days compressive strength of the concrete was 33.74N/mm2.
Original Research Article
July 29, 2022
Self-Potential; Thinking Style, Emotional Response, and Communication Patterns for New Students at the University of Lampung (UNILA) in 2021
Muhammad Nurwahidin, Moch Johan Pratama
Page Numbers : 192-196
DOI : 10.36348/sjce.2022.v06i07.003
The purpose of this study is (1) to analyze how the type of thinking style of UNILA new students in 2021. (2) to analyze how the type of emotional response of UNILA freshmen in 2021. (3) to analyze the types of communication patterns of UNILA new students in 2021. Research this was carried out simultaneously with the moment of orientation for new students at the University of Lampung in 2021. Descriptive quantitative research methods were used in this study. The subjects in this study were 5,065 new UNILA students in 2021. The survey method was used in this study. The data were analyzed using descriptive qualitative analysis using the SPSS version 22 application tool. The researcher found that (1) the majority of new students (43.3%) had a reflection type of thinking style. (2) the majority of new students (38.7%) had emotional response pattern with empathic type. (3) the majority of new students (43.4%) have a patterned communication pattern.