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Assessing Liquefaction Potential in Alluvial Plains Through Spatiotemporal Analysis Using Liquefaction Probability Index
Get PDFLiquefaction is one of the most important processes in soil dynamics. It is a loss of strength coupled with a rapid increase in pore pressure, causing soil particles to burst for a short period. Several approaches have been developed to calculate the residual or liquefied shear strength of cohesionless soils. Using the liquefaction probability index (LPI) created by Juang et al. (2003), the primary goal of this publication is to map spatiotemporal variations in the liquefaction potential of deposits in the Oued Drader and Marja Zerga alluvial plains of the mio-plio-quaternary Gharb basin. The cone penetration test (CPT) and semi-empirical techniques developed to measure the risk of liquefaction and create a mapping of liquefiable zones on a national scale for the first time are the primary sources of information used in the computation of the liquefaction potential index (LPI), which will be highly applicable and relevant for upcoming research projects. According to the IPL calculation, liquefaction is expected to be confirmed for the sandy and silty-sandy formations in Oued Drader and Marja Zerga. The spatial-temporal variations will depend on the formation's granulometry, saturation level, and liquidity limit. The lateral and spatial variety of the Marja Zerga and Oued Drader plain deposits is reflected in this architecture of liquefaction variation. Doi: 10.28991/CEJ-2024-010-06-018 Full Text: PD
Optimizing Landfill Site Selection Using Fuzzy-AHP and GIS for Sustainable Urban Planning
Get PDFCareful landfill selection with minimal environmental impact is vital for urban planners. This study aims to identify suitable sites for controlled landfills using Fuzzy-AHP integrated with Remote Sensing and GIS, considering a 20-year projection of population and solid waste generation. Initially, twelve sub-criteria were identified, grouped into environmental, socio-economic, and physical categories, and then weighted using paired comparison matrices involving nine experts. The sub-criteria were rasterized and classified into four suitability levels. The weighted overlay of sub-criteria maps generated a territorial suitability model. Within the Alto Utcubamba Commonwealth (Amazonas, Peru), 0.069%, 41.70%, 66.934%, 0.20%, and 12.4% of the territory are suitable, moderately suitable, less suitable, unsuitable, and restricted, respectively, for landfill establishment. Subsequently, 16 highly suitable sites were selected based on the required area (S4 polygons ≥ 0.505 ha) in line with the projected solid waste generation over 20 years. Of the 16 selected areas, only 15 met the shape index. The model showed high accuracy (AUC = 0.784) during validation. Furthermore, this study provides a comprehensive framework for making decisions about waste management in developing countries, enhancing understanding of key factors in selecting landfill sites. It also offers a deeper insight into global and local factors that determine the suitability of landfill sites. Doi: 10.28991/CEJ-2024-010-06-01 Full Text: PD
Utilization of Hybrid SIFCON to Improve Performance and Properties of Slab System Openings
Get PDFThis research aims to enhance Slurry Infiltrated Fibrous Concrete (SIFCON) by incorporating both long and short fibers, with the goal of increasing ductility and mechanical properties behavior. The study also evaluates the effectiveness of SIFCON in strengthening two-way reinforced concrete slabs with large openings. Various SIFCON mixes were created, integrating hooked-end fibers, micro steel fibers, and different volume ratios (Vf) of hybrid steel fibers (one-third, one-half, and two-thirds). A reference mix with 2% hybrid fiber-reinforced concrete (SFC) was formulated for comparison. Hybrid SIFCON samples demonstrated superior mechanical properties compared to those reinforced with hooked fibers, showing higher compressive strength, cylinder compressive strength, flexural strength, and direct tensile strength by 14%, 13.9%, 38.2%, and 58.2%, respectively, at 28 days, but a lower splitting tensile strength by 24%. Compared to micro steel fiber-reinforced samples, hybrid SIFCON exhibited higher compressive strength, cylinder compressive strength, flexural strength, and splitting tensile strength by 18.2%, 51%, 167.5%, and 43.6%, respectively, but a lower direct tensile strength by 7.4%. The study involved nine two-way square slabs with various mixtures of normal concrete, mortar-infiltrated fiber concrete, and full SIFCON. Control samples were constructed using normal-strength concrete. The application of SIFCON increased punching shear strength by 3.21% to 154.25% compared to the control samples. Doi: 10.28991/CEJ-2024-010-11-07 Full Text: PD
Utilizing Recycled Sand from Excavation Wastes for Sustainable Cement Mortar Production
Get PDFThis research investigates the feasibility of using recycled sand produced from excavation waste as natural sand alternative for sustainable cement mortar production. Two different types of recycled sand, namely limestone powder (RS1) and scalping powder (RS2), were collected and characterized. Thorough characterization encompassed particle size distribution, morphology, specific gravity, water absorption, and chemical composition. The recycled sands are then utilized to replace natural sand in mortar compositions, with varying proportions reaching up to 20%. The properties of the produced mortars were examined using the following tests: compressive strength, workability, density, water absorption, and thermal stability via thermogravimetric analysis (TGA). The results revealed that the inclusion of RS in cement mortar led to a decrease in compressive strength and workability, coupled with an increase in water absorption for both types of recycled sand. The decline in strength became more pronounced with higher RS proportions, with RS1 demonstrating superior compressive strength compared to RS2. Despite these effects, the thermal stability of cement mortar was only marginally impacted by the presence of RS. This research underscored the promise of recycled sand from excavation waste in cement mortar production, highlighting performance characteristics and suggesting further investigation, especially regarding thermal behavior under elevated temperatures. Doi: 10.28991/CEJ-2024-010-06-012 Full Text: PD
Performance of Asphalt Mixtures Modified with Nano-Eggshell Powder
Get PDFPrimary issues in pavement engineering, such as rutting, moisture damage, and fatigue cracking, have prompted numerous studies aimed at improving pavement performance. Utilizing biomaterial waste to modify bitumen through nanotechnology is a promising approach to improve asphalt-mixture properties and aligns with goals of sustainability and reducing the dependence on non-renewable resources. Therefore, the primary objective of this study was to investigate the effect of nano-eggshell powder (NESP) as a sustainable bio-modifier for bitumen on the mechanical properties of asphalt mixtures. To achieve this, asphalt mixtures containing 0% (control), 5%, and 9% NESP were developed, and their mechanical properties were investigated through various tests such as moisture damage, Marshall immersion stability, resilient modulus, dynamic creep, double-punch shear, water immersion, and wheel tracking. The results showed that NESP reduced the moisture susceptibility of the mixtures by increasing their tensile strength ratio. Additionally, the durability of the asphalt mixtures improved as the NESP content was increased. Moreover, the addition of NESP significantly enhanced the resilient modulus and dynamic creep of the asphalt mixtures. The double-punch test revealed that the NESP improved the rutting and fatigue resistance of the asphalt mixtures. Furthermore, the water-immersion test indicated that NESP enhanced the adhesion properties between the bitumen and the aggregate. Finally, the wheel-track test results suggested that the mixtures modified with NESP exhibited a lower rut depth than the control mixtures. Notably, 9% NESP was optimal for enhancing the mechanical properties of the asphalt mixture. The study demonstrated that using NESP as a bio-modifier for bitumen is feasible and offers a more sustainable alternative to traditional bitumen additives. Doi: 10.28991/CEJ-2024-010-11-016 Full Text: PD
Leak Detection in Urban Hydraulic Systems Using the K-BiLSTM-Monte Carlo Dropout Model
Get PDFUtility companies lose approximately 35 liters of water for every 100 produced due to incorrect, illegal connections and the poor condition of pipes. This study develops an intelligent model to detect leaks using the Kalman filter, BiLSTM neural networks, and the Monte Carlo Dropout algorithm. Using data from the Empresa de Acueductos y Alcantarillados de Bogotá (EAAB), Colombia, autocorrelation analysis, PCA, cluster analysis, ADF and Durbin-Watson tests, Hurst exponent, spectral analysis, and wavelet transform were performed. Then, Kalman filtering techniques were applied, and a BiLSTM architecture controlled with Monte Carlo dropout was implemented. The results showed an accuracy of 87.48% in training and 80.48% in validation. Temporal analysis revealed a stationary behavior in the flow series, and the decrease in spectral intensity around 0.25 Hz was related to pressure perturbations caused by leaks. A detailed evaluation of pressure and flow signals identified leak patterns with high precision, demonstrating the effectiveness of the wavelet spectrogram in detecting energy disturbances. The novelty of the study lies in the integration of advanced artificial intelligence and combinatorial optimization techniques to improve water resource management, allowing early and accurate detection of leaks, significantly improving compared to traditional methods. Doi: 10.28991/CEJ-2024-010-07-01 Full Text: PD
Effectiveness of Different Configurations of Ferrocement Retrofitting for Seismic Protection of Confined Masonry: A Numerical Study
Get PDFA ferrocement layer, which consists of a wire mesh and cement mortar, is a popular retrofitting method for existing structural elements, particularly wall or slab panels. This paper presents a study on the effectiveness of different configurations of ferrocement for seismic retrofitting of confined masonry through finite element analysis. The masonry panel was modeled using expanded brick-unit elements, where the element was expanded in size by as much as half of the mortar thickness, and an interacting zero-thickness interface was applied to mimic the elastic-plastic and damage behavior during tension, shear, and compression. The concrete damage plasticity (CDP) model was used to model the confining reinforced concrete frame and overlay mortar in the ferrocement layer, and the reinforcing bars and wire mesh were modeled using elastic-plastic behavior. In the present numerical study, nine models were subjected to cyclic and pushover shear test simulations, considering the effects of the number of ferrocement layers and the wire mesh orientation. The volumetric ratio of the wire mesh to the masonry (Ïwm) ranged from 0.48% to 1.92%, whereas the ratio of the mortar overlay to the masonry (Ïmo) varies from 10.42% to 41.66%. Based on the increase in the lateral strength, the model with the largest volume of the ferrocement layer exhibited the largest increase in strength. However, the most cost-effective retrofitting configuration was presented by model DS-1-45, in which a single layer of ferrocement was applied on both sides of the wall using 45° of wire mesh orientation. The DS-1-45 model provided a lateral strength increase of more than 6 times compared to the original unreinforced model. Doi: 10.28991/CEJ-2024-010-09-02 Full Text: PD
A Formula for Predicting Primary Settlement of Tropical Highly Organic Soil and Peat in the Field
Get PDFHighly organic soil and peat are problematic soils due to their low bearing capacity and high compressibility. In tropical regions, the presence of woody material in these soils often affects the stress-compression and time-compression curves in load-increment consolidation tests, leading to unusual shapes. Consequently, conventional inorganic soil theory and the Cα/Ccconcept are inadequate for analyzing their compression behavior. As an alternative, the Gibson and Lo model can be used to obtain compression parameters from single-load consolidation tests. However, this method introduces considerable discrepancies when predicting the primary settlement. To address this issue, this paper proposes a formula for predicting the primary settlement in highly organic soil and peat in the field, especially in tropical regions. Samples were collected from several locations in Indonesia. The formula was constructed from the stress-strain relationship during the primary compression stage, obtained from numerous single-load consolidation tests. Long-term field settlement is predicted by combining this empirical equation for primary settlement with the Gibson and Lo model for secondary settlement. The proposed formula was verified using field soil monitoring data, demonstrating reasonable accuracy in predicting the primary settlement of highly organic soil and peat. Doi: 10.28991/CEJ-2024-010-11-03 Full Text: PD
Experimental Investigation on Pervious Recycled Aggregate Concrete Made of Waste Porcelain
Get PDFThe current study examines the physical, mechanical, and durability of eco-efficient pervious concrete produced with partial and complete substitutions of natural aggregate (NA) by recycled aggregate (RA) waste from demolished concrete and porcelain. The experimental investigation assessed the workability (slump test), compressive strength, flexural strength, and tensile strength along with the concrete's water permeability, impact, and abrasion resistance. Seven mixes were examined; the first is a control mix with natural aggregate, and the other six are made with various RA ratios, including 30%, 70%, and 100%. The sand was also fully replaced by waste porcelain, even though the ratio of sand used in pervious concrete was low. The results revealed that using waste concrete and porcelain adversely affected the workability of fresh pervious concrete mixes, reducing it by approximately 14%. Furthermore, a decrease in the strength of pervious concrete was noticed, especially in the splitting tensile strength, where the reduction reached 32%. Moreover, the impact resistance of pervious concrete made with RA reduced by 29% compared to that made with NA; the same applies to durability, with an increase of 20% in weight loss. On the other hand, using both recycled concrete and recycled porcelain improved the permeability of the pervious concrete, which reached 30%. Pervious concrete made with waste concrete and porcelain can be an acceptable alternative to that made from natural aggregate due to its improved water permeability and positive environmental impact. However, further investigation is important to consider strength and durability enhancement. Doi: 10.28991/CEJ-2024-010-09-08 Full Text: PD
Evaluating the Rutting Resistance of Asphalt Mixtures Containing Waste Steel and Treated Recycled Concrete Aggregate
Get PDFUsing treated recycled concrete aggregate (RCA) in asphalt with waste steel reinforcement benefits the economy and the environment while delaying asphalt pavement deterioration. This study examined the impact of using RCA in several percentages reinforced by three dosages of waste steel: 0.3, 0.6, and 0.9 added as a proportion of mixture weight. The RCA was immersed in a 0.1M Hydrochloric acid solution for one day to treat the weak cement mortar in RCA and reduce the thickness of this layer. The assessment was carried out in a laboratory using the typical Marshall test to determine the optimum quantity of asphalt contents, the volumetric properties of asphalt mixtures, and the wheel tracking test; the study involved ten rectangular slabs measuring 30í—40í—5 cm, and they were repeatedly subjected to 700 N wheel loads at 55°C to test their rut resistance. According to the study, while Marshall's stability increased, adding waste steel and RCA did not significantly alter the volumetric properties of asphalt mixes. The greatest improvement in Marshall stability, 45.18% over the conventional mix, was seen in the mix, including 75% RCA and 0.9% waste steel. The rutting performance decreased with the addition of RCA and rose with the inclusion of waste steel. The results indicate that adding waste steel to asphalt mixtures effectively increases the rutting resistance. The mixture with 50% RCA and 0.9% waste steel showed less rutting depth of 25.01% than the conventional mix. Doi: 10.28991/CEJ-2024-010-11-011 Full Text: PD