Civil Engineering Journal (C.E.J)
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    859 research outputs found

    Effect of Bonding Area on Bond Stress Behavior of GFRP Bars in Concrete

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    The application of Glass Fiber Reinforced Polymer (GFRP) bars is suitable for concrete structures that are susceptible to corrosion, owing to their corrosion-resistant characteristics. Therefore, it is feasible to reduce the concrete cover on reinforced concrete beams by utilizing GFRP bars. However, this can reduce the bonding strength between GFRP bars and concrete. Therefore, this study aims to investigate the bonding behavior between GFRP bars and concrete as a preliminary test for structural applications. The bond stress behavior between GFRP bars and concrete was analyzed by 18 pull-out tests. The test specimens comprised GFRP bars with three different variations, namely GFRP bars with concrete cover (GFRP-C), GFRP bars without concrete cover (GFRP-E), and GFRP bars with a complete wrapping of GFRP sheet (GFRP-C-Sheet). The bond stress-slip curve, bond strength, and failure pattern were utilized to analyze the effect of each variation. The research results indicate that the bonding stress between GFRP bars and concrete was strongly influenced by the concrete cover, where the bonding strength decreased by 65%. Nevertheless, the utilization of a complete wrapping GFR) sheet resulted in a 26.4% increase in bonding stress. The present study has identified three distinct modes of failure, including pull-out (GFRP-C), concrete crushing (GFRP-E), and GFRP sheet debonding (GFRP-C-Sheet). Doi: 10.28991/CEJ-SP2023-09-010 Full Text: PD

    Improving CBR Parameter of Expansive Soil Using the Carbonate Precipitation Method with Tofu Waste as a Biocatalyst

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    Expansive soil is problematic from an infrastructural perspective, including the subgrade of pavement construction. The high swelling and shrinkage of this soil promotes subgrade imbalance, resulting in severe pavement construction problems. One potential soil improvement method is the carbonate precipitation method; however, this method requires a catalyst. This research aims to evaluate the use of tofu waste as a biocatalyst in the carbonate precipitation method to improve expansive soil. Several variations of tofu waste reacted with reagents (urea and calcium chloride) as treatment solutions. Soil identification, hydrolysis, precipitation, Atterberg limits, California bearing ratio (CBR), scanning electron microscopy (SEM), and X-ray diffraction (XRD) tests were performed. The results showed that the optimum tofu waste concentration was 40 g/L. The swelling ratio in the soil treated with carbonate decreased by 12.5%. The CBR value of the treated soil also increased by 23.9%. The SEM and XRD analysis results showed the formation of aragonite, calcite, and vaterite. Moreover, this study confirmed that tofu waste is a promising biocatalyst for carbonate precipitation. Doi: 10.28991/CEJ-SP2023-09-013 Full Text: PD

    Evolution of Durability and Mechanical Behaviour of Mud Mortar Stabilized with Oil Shale Ash, Lime, and Cement

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    The investigation into earthen construction technologies and materials is now acknowledged as a crucial area requiring further research. Earthen mortars are prevalent in both modern and traditional construction due to the abundance of earth material, their favorable thermal properties, and their low embodied energy. The objective of this study is to support the use of natural materials collected from north Jordan to enhance the mechanical properties and durability of mud mortar. The local soil was stabilized using Oil Shale Ash (OSA), Ordinary Portland Cement (OPC), and lime for producing mud mortar. Particle size analysis, plastic limit, liquid limit, XRD, and XRF were applied to assess the geotechnical characterization and mineral composition of the earthen stabilizers and local soil. In order to examine the mechanical properties (specifically compressive strength) and durability characteristics (such as water absorption and shrinkage) of mud mortar, a total of 8 mixtures were prepared. One of these mixtures served as a control, while the others were created by substituting soil with varying proportions of OSA, cement, and lime. The results show that the mud mortar contained 10% OSA and 10% cement, which exhibited the highest compressive strength. Moreover, an increase in the proportion of OSA in the soil led to a decrease in absorption and linear shrinkage, indicating that OSA is an effective stabilizing agent for mud mortar. Doi: 10.28991/CEJ-2023-09-09-06 Full Text: PD

    Seismic Risk Assessment and Rehabilitation Method of Existing RCC Structures Using Micro Concrete

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    Aging reinforced concrete (RC) building structures typically experience more severe damage and are prone to collapse during earthquakes, constituting a primary factor in casualties and direct economic losses. To enhance the seismic performance of these old structures, this paper proposes a seismic risk assessment and a micro-concrete restoration method. It applies the process to an existing three-story reinforced concrete structure. A practical framework for mitigating structural vulnerabilities in seismic-prone regions was proposed. Then an as-built survey was conducted to create as-built architectural and structural drawings. Concrete core tests, ferroscans, and rebar tests were also performed. Based on field surveys and test data, nonlinear static and dynamic analyses have been used to evaluate structural safety. Concrete column jacketing was used to strengthen weak existing columns with micro-concrete. In assessing the structural response of retrofitted buildings, a comparison was made to their initial state. The comparison shows that applying concrete column jacketing with micro concrete can reduce other structural elements' demand capacity ratio (DCR), minimize maximum displacements, and enhance overall stiffness. The results indicate that the proposed method effectively evaluates the seismic risk of aging structures and enhances seismic resilience in existing buildings. Moreover, the application to the actual structure demonstrates that micro-concrete is highly durable and compatible with parent-concrete. Doi: 10.28991/CEJ-2023-09-12-04 Full Text: PD

    Compilation of Parameter Control for Mapping the Potential Landslide Areas

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    Batu Tourism City is located in a mountainous area, so based on information from the BNPB, it has quite a large potential for landslides. Landslide hazards can frequently disrupt public traffic due to road cuts. Landslide mapping digitally will contribute to handling and mitigation activities since the database can be updated in real time to anticipate landslide hazards. This study aims to map landslide-prone areas located in the Payung zone, Songgokerto Village, and Batu City. Landslide areas can be determined by mapping analysis using GIS software. GIS can determine the classification level for a landslide susceptible area. Some input data that will influence landslides, such as rainfall, wind, earthquakes, etc., was collected as the control parameters. All parts of the study area could be classified as areas with minor, medium, and major potential for landslides. Primary data are collected from geo-surveying (aerial images) using drone devices for interpretation of landslide susceptibility areas, geophysical to identify the type of soil or rock layers that completed their behavior, and slip planes as well using geo-electric, geotechnical engineering to predict slope stability with the correlation from cone penetration test (CPT) data, and geo-hydraulic to observe the rainfall and the catchment area model using the available secondary data. Geometrically, measurement data found that the average slope angle at the upper and lower of the East Java Province highway is around 40–50o. Studies from geophysical data identified that the hilly terrain in the object study area has been dominated by the weathered rock layer. Geotechnical data obtained shows the soil layers at the slope location will be stable with the water content under 35% during the dry season and may become unstable with the water content reaching over 50% due to the increase in saturation during the rainy season. The landslide that occurred was more caused by seepage behavior from surface water flow towards the sloping plane, and then the safety factor during the rainy season reached the critical values at SF = 0.58. During the dry season, the unsaturated process due to the temperature change generates a safety factor (SF) of more than 1.2. The compilation data produced maps of susceptible landslides and surface flow distribution. Doi: 10.28991/CEJ-2023-09-04-016 Full Text: PD

    Numerical Analysis and Parametric Study on Multiple Degrees-of-Freedom Frames

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    The design of multiple degrees-of-freedom frames is critical in civil engineering, as these structures are commonly used in various applications such as buildings, bridges, and industrial structures. In this study, a six-degrees-of-freedom beam-column element stiffness matrix was formulated by superposition of beam and truss elements stiffness matrices and was adapted to statically analyze indeterminate frame structures. The development of a numerical model for the frame structures was achieved using the finite element method in the current study. Also, the investigation of the effects of various parameters such as frame geometries, material properties, and loading conditions was conducted on the internal forces developed in the frame structures. Three different parametric study cases that presented the frame structures with varying geometries and loading conditions were analyzed utilizing this matrix approach for the sake of emphasis and to evaluate the flexibility and adequacy of this formula to analyze the indeterminate frames using the MATLAB software. The analysis method comprised the derivation of the system displacements employing the relationships between the stiffness matrix and fixed end forces as the force vector and taking the attained displacements, which would be transformed to the local coordinates to obtain the member forces. The computed results from the element stiffness matrix approach were further statistically compared with the results achieved from the finite element software (SAP2000) applying the analysis of variance (ANOVA). The statistical results showed a P-value > 0.05, which indicated a good correlation between the compared results and adequate performance for the derived beam-column element matrix formula method. Doi: 10.28991/CEJ-2023-09-07-012 Full Text: PD

    Effect of Openings on the Torsional Behavior of SCC Box Beams Under Monotonic and Repeated Loading

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    Repeated Torsional loading occurs in many concrete structures, such as offshore structures, freeways, multistory parking garages, and other structures; however, repeated torsional loading is still poorly understood. This study aims to investigate the effect of openings on the ultimate and cracking torques, angle of twist, and modes of failure of self-compacted R.C. box beams under monotonic and repeated loading. Two groups of eight half-scale box beams with different numbers of circular openings in the web with a diameter of about 30% of the hollow box dimension were investigated. The first group (I) included four beams: one was the control box beam without openings, whereas the rest of the beams were hollow with one, two, or three openings in the web tested under monotonic loading. The second group (II) consisted of the same details as the first one tested under repeated loading. The range of the repeated loading was about 30% and 60% of the ultimate load of the monotonic tests. The study showed that the cracking and ultimate torques and the angle of twist of the tested beams were significantly reduced due to openings in the web. Results revealed a more pronounced effect for monotonic loading, with a maximum reduction of 20% and 26.8% in cracking and ultimate torsional strength, respectively, compared to monotonic loading. Moreover, results revealed that repeated loading causes inelastic deformations in proportion to the number of loading cycles. Doi: 10.28991/CEJ-2023-09-09-015 Full Text: PD

    Potential Erosion in Mining, Oil Palm Plantations, and Watersheds Reforestation Areas

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    Erosion forecasting is a complex issue generated by numerous causes, the extent of which varies based on the unique area and conditions. Changes in rainfall, land cover, and watershed function are the primary causes of increased erosion. This study aims to scrutinize the actual and potential erosion in the mining area (MA), oil palm plantations (OPP), and watersheds reforestation (WR) in Asoloe, South Konawe, Indonesia. We utilized qualitative research methods and surveys with the USLE model. MA shares the highest actual erosion with 332.30 tons/ha/year, with an average erosion of 27.69 tons/ha/year from 2011 to 2022. Meanwhile, the potential erosion is 4747.19 tons/ha/year, with an average of 395.60 tons/ha/year. In terms of current conditions, 44.6% of rainfall engenders erosion with more than 0.5 t/ha and 33.9% with more than 1 t/ha. This study successfully demonstrates that for given location and area characteristics, high amounts of rainfall and changes in land function eminently affect soil erosion and that the potential erosion changes that occur in the Asoloe watershed every year are exceptionally influenced by changes in land use and land function. Therefore, some mitigation strategies and policies must be taken to reduce the risk of future erosion. Doi: 10.28991/CEJ-2023-09-09-07 Full Text: PD

    Laboratory Innovation to Investigate Concrete Paving Blocks Compressive Strength

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    This research aims to evaluate the block method against the cube test method using variations in thickness. Paving blocks can be produced using a hydraulic machine or a simple press, and their performance can be measured based on density and compressive strength tests. The block test method shows that with the same material composition forming the paving block, a paving block with a higher thickness can lead to a lower compressive strength value. In contrast, the cube test method shows different results. The paving blocks used in this study had width and length sizes of 100 and 200 mm, respectively, and had varying heights of 60, 80, and 100 mm. The results reveal that the compressive strength of concrete paving blocks is more precise based on density. Furthermore, the empirical equation and conversion coefficient of the compressive strength of the block test to the cube test have been obtained. This empirical equation is highly recommended for the road pavement industry in controlling the quality of compressive strength, even when using block tests. Further research can help develop a formula for using additive materials in paving blocks. Doi: 10.28991/CEJ-2023-09-11-03 Full Text: PD

    Effect of Class F Fly Ash on Strength Properties of Concrete

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    Reducing the amount of CO2 emissions in the environment is one of the priorities of the EPA and other environmental agencies. A way to reduce CO2 emissions is by using fly ash in the concrete industry. Aside from environmental benefits, fly ash has numerous quality advantages; some of the positive effects were recognized earlier; however, in this research, the objective is to replace cement with a different percentage of class F fly ash with a low CaO content to produce sustainable concrete. Laboratory tests were performed to examine the rational percentage of cement replaced by class F fly ash in ordinary concrete C–25/30 and high-performance concrete C–50/60. In total, twelve different mix designs were prepared to examine consistency, setting time, shrinkage, and compressive strength in different periods of curing for more than 600 days. Using recycled material in new buildings still has some obstacles, but the future of construction must be green, so this research indicates that the objective of producing ordinary and high-performance concrete was achieved by replacing 30% of cement with class F fly ash. Doi: 10.28991/CEJ-2023-09-09-011 Full Text: PD

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    Civil Engineering Journal (C.E.J) is based in Iran
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