2031 research outputs found
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Mechanical Properties of Cement-Stabilized Sandy Soils Modified with Consoil
Get PDFThis study investigates the mechanical enhancement of sandy soils through cement stabilization modified with Consoil, targeting improved pavement substructure performance. Unconfined compressive strength (UCS) tests were conducted on samples with varying cement contents (3%, 6%, 9%), Consoil dosages (0%, 5%, 10%, 15%, 20% by cement weight), and curing periods (3, 7, 28, 90 days). Field Emission Scanning Electron Microscopy and X-Ray Diffraction analyses complemented mechanical testing to understand strengthening mechanisms. Results demonstrated that 15% Consoil consistently optimized strength development across all cement contents, with 9% cement and 15% Consoil achieving peak 90-day UCS of 17.74 MPa, representing a 67% increase over control samples. Microstructural analysis revealed progressive matrix refinement with increasing Consoil content, while XRD indicated enhanced pozzolanic activity through calcium hydroxide consumption. The study introduces Consoil as an effective stabilization additive, establishing optimal dosage rates and demonstrating significant strength improvements through synergistic cement-Consoil interactions. The findings provide new insights into strength enhancement mechanisms in Consoil-modified cement-stabilized soils, offering practical guidelines for designing high-performance pavement substructures. The research contributes to sustainable construction practices by optimizing cement usage through Consoil incorporation. Doi: 10.28991/CEJ-2025-011-01-011 Full Text: PD
Enhancing Construction Safety Evaluation Through a Standardized Rating Tool System
Get PDFIndonesia has achieved considerable advancements in infrastructure development over the past decade; yet, the incidence of work-related accidents in the construction sector continues to be elevated. Data indicates that the rising trend of infrastructure projects in Indonesia correlates with the annual increase in work-related accidents. This signifies that a construction safety issue persists. Despite the establishment of pertinent rules, the execution of the construction safety management system remains suboptimal. Noncompliance with safety rules is a primary contributor to construction accidents. Consequently, measurement is essential to evaluate the enforcement of construction safety regulations. Regrettably, the execution of safety performance metrics in building projects has been inadequate. It is executed customarily using non-standardized parameters, differing from one project to another. This project seeks to create a rating tool system for assessing construction safety performance and to analyze the relationship model between information systems and safety rating tools in relation to construction safety performance. This study employs both qualitative and quantitative methodologies. The initial phase involved the development of an information system for measuring construction safety performance, utilizing characteristics derived via expert validation. The second stage examined the impact of the system on construction safety performance. The findings indicated that the information system and safety rating tools positively impact construction safety performance. Furthermore, the Safety Rating Tools system standardizes the assessment of construction safety performance, rendering it more straightforward and efficient. The evaluation results aim to enhance compliance to safety standards to prevent building mishaps. Doi: 10.28991/CEJ-2025-011-04-016 Full Text: PD
Nonlinear Finite Element Analysis of I-Steel Beam with Sinusoidal Web
Get PDFFor structural models, existing research frequently uses deterministic numerical analysis. Test findings, however, constantly point out uncertainties, especially about variables like the imposed load's amplitude, geometrical dimensions, material unpredictability, and inadequate experiential data. In response, scholars have focused more on probabilistic design models, realizing their importance for precisely forecasting structural performance. This research aims to incorporate reliability-based analysis into the numerical modeling of steel beams with sinusoidal webs. A steel welded plate beam with an I-section and a sinusoidal web has been taken into consideration in this study. The web height is 750 mm, the web thickness is 2.0 mm, the flange width is 300 mm, and the flange thickness is 5.0 mm. The beam's length, l = 1000 mm, has two 10.0 mm thick stiffeners positioned beneath the applied load to stop the flange from failing locally as a result of load concentration and end plate supports that are 5 mm thick. The commercial software application ANSYS ver. 2019 R3 has been used to perform a nonlinear finite element analysis in order to examine the failure modes and load capacities. In the first stage of this study, the changing of the amplitude/period ratio, A/P, was taken into consideration to examine the failure capacity loads and deformed shapes to optimize the amplitude/period ratio. In the second stage, the optimum amplitude/period ratio, A/P, was taken, and changing the period/span ratios, P/L, made the best use of the period/span ratios by examining the failure capacity loads and deformed forms. Doi: 10.28991/CEJ-2025-011-03-08 Full Text: PD
Consolidation Behavior of Soft Soil Treated with PVDs and Vacuum-Surcharge Preloading
Get PDFPrefabricated vertical drain (PVD) combined with vacuum-surcharge preloading is a widely used ground improvement technique to accelerate the dissipation of excess pore water pressure and reduce the soil compressibility. However, difficulties in the numerical simulations of water dissipation and equivalent permeability of soil with PVDs in three-dimensional (3D) and two-dimensional (2D) settings cause substantial deviation of numerical results from observational data. Moreover, the optimum length of PVDs has not been well documented. Accordingly, this work analyzes a project in Dong Nai, Vietnam, where a 37-meter-thick soft soil was treated with PVDs and vacuum-surcharge preloading. In this work, the field observations and finite element method with consolidation theory were used to analyze the ground settlements, lateral displacements, and excess pore water pressure. The observed and simulated data shows that (i) the rate of settlements in the first 60 days of increasing preloading pressure is about 2.1 times faster than that in the next 110 days of constant preloading pressure, (ii) at 170 days, the ground-surface lateral displacement at the toe of the embankment is around 50 mm and reaches its maximum value of 150 mm at 1.55 m depth, and (iii) the dissipation of pore water pressure is closely correlated with the settlement rate. Moreover, back analysis indicates that a permeability conversion ratio from 1.872 to 4.538 should be applied to achieve the same degree of consolidation between 3D and 2D models. Lastly, the optimum length of PVDs in this project is 28 m, around 76% of the fully penetrated length into the soft layer
Optimization Framework for ASIAN and National Road Networks in Lao PDR Using the Stochastic Markov Model
Get PDFDeveloping effective road network management is crucial for the socioeconomic development of developing countries, particularly the Lao People's Democratic Republic (Lao PDR or Laos). The current road maintenance system in Lao PDR uses a traditional reactive maintenance approach, addressing road deterioration only after the condition reaches a critical state. This study proposes a stochastic Markov Decision Process (MDP) framework to enhance traditional road management practices. The proposed MDP framework shifts from a conventional reactive to a proactive strategy by considering probabilistic pavement performance and optimally allocating funding to rapidly deteriorating sections. This study enables decision-makers to determine the optimal intervention strategies based on different scenarios. The comparison of the ASIAN Road network, high technical design and construction, and the National Road network, standard technical design and construction, in different scenarios provides a workable framework for maintaining Laos, and other developing countries, road condition despite limited resources and sustainable development concerns. This comprehensive framework includes estimating deterioration rates, defining policies, conducting life-cycle cost (LCC) analysis, and determining optimal strategies that minimize LCC subject to financial and performance constraints. This study highlights significant improvements in decision-making, particularly in resource allocation, by creating innovative and preventive approaches that enhance the efficiency of road management systems and ensure sustainable maintenance practices in Lao PDR. Doi: 10.28991/CEJ-2025-011-05-023 Full Text: PD
Influence of Bacillus Subtilis Bacteria on Strength and Durability of Concrete with Silica Fume
Get PDFThis study investigates the influence of Bacillus subtilis bacteria on the strength and durability properties of M30 concrete with and without silica fume. The experimental study was conducted on four concrete mix series: conventional concrete (B1), conventional concrete with silica fume (B2), bacterial concrete without any admixtures (B3), and bacterial concrete with silica fume (B4). Silica fume was incorporated at replacement levels of 5% and 10% by weight of cement for the B2 and B4 mix series to evaluate its effect on bacterial activity and concrete performance. The study measured compressive strength, split tensile strength, and water absorption to assess mechanical and durability properties. Results reveal that bacterial concrete (B3 and B4) exhibits improved strength and durability compared to conventional concrete (B1 and B2). Furthermore, silica fume enhances the performance of bacterial concrete due to its pozzolanic action, which refines the microstructure and provides additional nucleation sites for calcium carbonate precipitation by Bacillus subtilis. Among all mixes, B4 with 10% silica fume achieved the highest strength and durability, demonstrating the synergistic effect of bacteria and silica fume. This research highlights the potential of bacterial concrete with silica fume as an innovative material for sustainable construction, offering improved mechanical performance and reduced permeability. Doi: 10.28991/CEJ-2025-011-05-013 Full Text: PD
Response of Long-term Cyclic Laterally Loaded Monopiles in Sand
Get PDFThe offshore wind energy industry has grown rapidly, with large-diameter monopiles becoming the primary foundation choice for offshore turbines. Monopile designs emphasize serviceability and fatigue limits, enforcing strict rotation limits set by manufacturers. These structures face considerable lateral cyclic loads from waves, currents, and wind. Existing design codes such as API and DNV GL are commonly used but do not sufficiently capture monopile behavior under cyclic loading, particularly regarding load cycle count, amplitude, and type. Moreover, the dynamic response of the monopile-soil system, which affects the foundation’s natural frequency, depends on the pile-soil interaction stiffness—an aspect neglected in current standards. This research reports results from seventeen 1-g cyclic loading experiments and six monotonic tests on monopiles installed in dry sand. Findings reveal that cyclic deformation is significantly influenced by sand relative density, load cycle number, and cyclic load characteristics (magnitude and type). Cyclic loading also alters the pile-soil stiffness. Accumulated rotation grows exponentially with increasing load cycles, while cyclic secant stiffness increases logarithmically. The study further identifies asymmetric two-way cyclic loading as the most damaging load pattern for monopile performance
Infrared Thermal Monitoring of Intersection Elements of Urban Road Infrastructure and Road Traffic Via Drone
Get PDFThis paper presents a thermographic analysis of a street junction within an urban road network, focusing on identifying thermal load sources generated by vehicle traffic”an increasingly significant environmental concern for urban populations. The study explores the application of thermographic methods at urban intersections and the creation of thermal maps. These approaches support the advancement of intelligent transport systems, aligning with smart city initiatives aimed at optimizing traffic flow management. Additionally, the findings provide potential for assessing the conditions of both road transport infrastructure and vehicles. By adopting this comprehensive perspective for monitoring urban environments and transportation systems, cities can enhance overall quality of life and public well-being. The results emphasize the value of conducting broad-scope studies, suggesting that combining ground-based and aerial thermal imaging leads to more informed decision-making. Doi: 10.28991/CEJ-2025-011-05-02 Full Text: PD
A Novel One-Sided Push-Out Test for Shear Connectors in Composite Beams
Get PDFThe small-scale push-out test (POT) is widely utilized to investigate the characteristic behavior of shear connectors as an available alternative to full-scale beam tests, which are often costly and time-consuming. However, several researchers have expressed issues regarding the POT specimen setup during testing due to inconsistencies between the results of POTs and beam bending tests. In this paper, a new configuration for a one-slab POT is developed to address these issues. To validate the developed method of testing, several POTs and OSPOTs were conducted and compared against each other and with those of previous research. The load-slip curves obtained from the OSPOTs were then evaluated against the curves obtained from four empirical expressions. Furthermore, a database of different POT configurations and setups, specifically 114 tests, selected from the previous research that employed the 19 mm shear stud, was analyzed in detail. Subsequently, the results of these tests and the proposed OSPOT method were compared with the predictions offered by several empirical equations. The results indicated that the results of the OSPOT are more consistent with the codes and empirical equations compared to typical POT. Hence, this OSPOT setup could be used as an efficient and economic option for the POT, as it has the potential to double the number of results for the same resources and simplify the casting procedure, which is particularly significant when numerous tests are required for the experimental campaign. Also, the OSPOT results revealed more ductile behavior for the shear studs, which is consistent with the full-scale beams’ testing
Revolutionizing Recycled Aggregate Concrete: A Dual Approach Using HCl Treatment and Silica Fume
Get PDFDebris from building and demolition projects, as well as the shortage of natural resources, have become more pressing issues on a global scale in recent times. Even though concrete, the utmost adaptable building material, is a vital factor in the development of the infrastructural and industrial sectors, it has been claimed that it is not an environmentally friendly material due to its potential for profound environmental influence beyond its use and critical resource-consumption nature. Nevertheless, it will continue to be the dominant building material utilized globally. The present research aims to investigate the synergistic effects of the treatment of recycled concrete aggregate (RCA) by hydrochloric acid (HCl) and the replacement of cement by silica fume (SF) on the mechanical properties of produced concrete. Four groups of concrete mixes were prepared: (1) untreated recycled concrete aggregate (URCA), (2) HCl-treated recycled concrete aggregate (TRCA), (3) URCA with SF replacement, and (4) TRCA with SF replacement. The HCl treatment was applied at four molarities (0.2M, 0.4M, 0.6M, and 0.8M), while SF was used to replace cement by weight at four ratios (5%, 10%, 15%, and 20%). The results were evaluated in terms of the 7, 14, and 28-day compressive strength. The findings indicated that TRCA mixes significantly outperformed URCA mixes in terms of the mechanical properties, namely the 28-day compressive strength, in which the optimal mix was that with 100% TRCA by 0.4M HCl combined with 5% SF replacement. The results also demonstrated that 0.6M HCl treatment significantly enhanced the quality of RCA by removing weakly adhered mortar, leading to a nearly 21% rise in the 28-day compressive strength compared to URCA with complete replacement. Indeed, adding further SF enhanced the performance, as using 75% of TRCA+10% SF achieved the highest compressive strength of 38.7 MPa at 28 days, equalling around 25% improvement over the URCA with the same replacing level. Doi: 10.28991/CEJ-2025-011-05-08 Full Text: PD