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Mechanical Properties of Sustainable Base Course Binder Incorporating GGBFS and Spent FCC Catalyst
No full textThis study investigates the feasibility of utilizing ground granulated blast furnace slag (GGBFS) and spent fluid catalytic cracking (FCC) catalyst as partial cement replacements in pavement base course materials. Various blends of GGBFS and FCC catalyst were evaluated as binders for unbound granular base (UGB) material, with total binder content fixed at 10% by weight. Mechanical properties were assessed through unconfined compressive strength (UCS) and splitting tensile strength tests at 3, 7, 28, and 56 days. Microstructural analysis was conducted using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Results indicate that an optimal blend of 60% FCC and 40% GGBS achieved the highest UCS of 9.6 MPa at 56 days, exceeding typical requirements for cement-treated base materials. All investigated mix proportions surpassed the minimum 28-day strength requirement of 4 MPa for pavement base applications. Splitting tensile strength results corroborated compressive strength trends, with enhanced tensile-to-compressive strength ratios suggesting improved crack resistance potential. Microstructural analysis revealed a dense, well-reacted cementitious system supporting the observed mechanical performance. These findings demonstrate the technical feasibility and potential environmental benefits of incorporating high volumes of GGBS and spent FCC catalyst in pavement base materials, offering a sustainable alternative to conventional cement-based binders. Doi: 10.28991/CEJ-2025-011-03-012 Full Text: PD
Investigation of an Innovative Technique for R.C. Square Footing Reinforced by GFRP and BFRP Bars with HSC
No full textThe utilization of alternate reinforcement materials to improve footing capacity performance has garnered significant interest in recent years. Limited research has been conducted to understand the impacts of basalt reinforcement. This study aims to investigate the performance of the high-strength concrete (HSC) footing reinforced by alternative materials such as glass fiber-reinforced polymer (GFRP) bars and basalt fiber-reinforced polymer (BFRP) bars. This work contains experimental and finite element (FE) numerical modeling aimed at investigating the behavior and crack propagation of HSC footings. Axial load investigations were conducted on RC square footings with cross sections of 300í—300í—90 mm for different materials in reinforcing the RC footing, and an experimental investigation of mechanical properties has been carried out. The main reinforcement for the footing has been varied. Two types of material, namely, glass fiber-reinforced polymer (GFRP) bars and basalt fiber-reinforced polymer (BFRP) bars, were used. Four types of concrete mixture were used: normal concrete (NC), high-strength concrete (HSC), glass fiber-reinforced concrete (GFRC), and HSC+ glass fiber bristles. The experimental results demonstrated an improvement in the ultimate load by 28-49% and an enhancement in performance represented in the cracking pattern. Additionally, a 3D nonlinear finite element (FE) analysis utilizing Abaqus software was conducted to verify the numerical results with experimental findings; the results proved the suitability of the employed experimental setup. Doi: 10.28991/CEJ-2025-011-04-017 Full Text: PD
Bond Strength Evaluation of Waterproofing Membrane Assembly in Concrete Bridges
No full textOn the concrete bridge decks overlaid by HMA, slippage cracks usually appear on the HMA layer because of the presence of waterproofing membranes below the HMA layer and a lack of bonding of the membrane with the PCC underlying layer. The objective of this work is to develop a laboratory-based method for the fabrication of test samples of an HMA layer, waterproofing membrane, and PCC layer system. In addition, a bond strength test procedure was adapted to evaluate the bonding of the three layers assembly at different test temperatures in the laboratory prior to the field application. According to the obtained evaluation results, it was found that the weakest bond in the HMA, waterproofing membrane, and PCC assembly is the bond between the HMA layer and the waterproofing membrane. The bond strength of the assembly is highly affected by increasing temperature, since it lost approximately 75% of its strength when the test temperature increased from 25°C to 50°C. Likewise, as the test temperature increased from 25°C to 60°C, the assembly lost approximately 75% of its strength. Therefore, the bond strength should be evaluated at the expected pavement temperature in the field, specifically at the membrane interface level. Doi: 10.28991/CEJ-2025-011-02-010 Full Text: PD
IRI Performance Models for Flexible, Semi-Rigid and Composite Pavements in Double-Carriageway Roads
No full textPavement Management Systems (PMS) depend upon reliable pavement performance models. In this paper, our aim is to develop International Roughness Index (IRI) prediction models for the heavily trafficked (right-hand) lanes of motorways in the province of Gipuzkoa (Spain) in flexible, semi-rigid, and composite pavements. A deterministic approach was selected, based on the available information in the PMS employed in that province, covering complete pavement structures. Omitting pavement type, the model yielded a determination coefficient (R²) of 0.696 with only three variables: pavement age, cumulative volume of heavy vehicles travelling through the section, and total thickness of bituminous layers. Then, two superior models were generated with pavement type as a variable, yielding R²values of 0.781 and 0.795, respectively. Unlike the opaque features of Machine Learning (ML), the deterministic models captured precise relationships between the variables to a high degree of accuracy. They can moreover be applied to all pavements with bituminous layers, unlike many other models that are only applicable to a single pavement type. Furthermore, the models are presented for freeways where traffic is randomly distributed between lanes; a less widely covered topic in the literature. Doi: 10.28991/CEJ-2025-011-05-01 Full Text: PD
Advanced Reclaimed Asphalt Pavement Treatment for Sustainable Pervious Concrete: Optimizing Strength, Hydraulic Performance and Long-Term Durability
No full textThe increasing depletion of natural aggregates and escalating construction waste necessitate the implementation of environmentally friendly substitutes in concrete production. This study explores the incorporation of treated Reclaimed Asphalt Pavement (RAP) as an eco-efficient alternative to traditional coarse aggregates in pervious concrete (PC) matrices by evaluating its structural integrity, permeability, durability, and microstructural characteristics. A comprehensive multi-stage treatment process involving solar heating, natural oxidation, and mechanical roughening was employed to enhance aggregate bonding and bitumen reduction. The treatment of RAP was conducted for three treatment durations: 0-month, 12 months, and 24 months. Coarse aggregates were substituted with 0%, 25%, 50%, 75%, and 100% RAP by weight, and all mixtures were cured for 90 days. The investigation focused on evaluating essential functional characteristics, including density, porosity, hydraulic conductivity, compressive and flexural responses, as well as durability under abrasion and chemical exposure to sulphate and chloride environments. Microstructural analysis utilizing Energy Dispersive X-ray Analysis (EDAX) demonstrated a substantial reduction in bitumen content, as evidenced by a declining carbon peak with increased treatment duration. Additionally, Scanning Electron Microscopy (SEM) micrographs revealed fewer voids, increased C-S-H formation, and improved bonding, with minor Interfacial Transition Zone (ITZ) variations across 12-month and 24-month treatments. The findings highlight that extended RAP treatment significantly improves density, reduces porosity, enhances compressive and flexural strength, and lowers permeability. Furthermore, 24-month treated RAP demonstrated superior durability, exhibiting enhanced abrasion and chemical resistance due to improved aggregate cohesion and matrix integration. This study establishes that pervious concrete with more than 50% RAP content, previously considered unviable, is structurally feasible when suitable treatment and gradation techniques are used, thereby advancing sustainable construction materials. Doi: 10.28991/CEJ-2025-011-04-019 Full Text: PD
Correlation of Methylene Blue Value with the Behavior of Natural and Stabilized Expansive Soils
No full textThis study investigates the expansive nature of soils from various regions in Indonesia, focusing on their natural and post-stabilization characteristics. The research aims to bridge the gap in understanding the relationship between Methylene Blue Value (MBV) and soil expansivity, both in natural and stabilized states. Soil samples were systematically collected from seven locations across three Indonesian islands and subjected to a range of laboratory tests, including X-ray diffraction analysis, to determine their properties and mineral composition. Compaction and swell tests were conducted to establish Maximum Dry Density (MDD) and Optimum Moisture Content (OMC), as well as swell pressure and free swell parameters. The study further explored soil improvement techniques using cement and lime stabilizers at varying concentrations from 5% to 15%. The results indicated that both cement and lime significantly reduce swell pressure and free swell, with a 15% additive concentration being optimal for mitigation. The analysis revealed a strong correlation between MBV and soil expansivity, with higher MBV values indicating greater expansivity. Regression analysis showed a non-linear relationship between MBV and swell pressure, explaining 97.8% of the variation in swell pressure. Additionally, a linear relationship between MBV and the expansive mineral content was identified, suggesting that the Methylene Blue Test can serve as a cost-effective and rapid substitute for identifying expansive minerals in the soil. The findings highlight the reliability of MBV as an indicator of soil behavior and its potential application in predicting soil expansivity. Doi: 10.28991/CEJ-2025-011-05-020 Full Text: PD
Examining Social Acceptability of Solar Innovations in Smart Cities
No full textObjective: The global challenge of climate change and the need for energy conservation have prompted a reevaluation of energy sources and policies worldwide. This study aims to investigate the societal acceptability of solar photovoltaic (PV) systems among citizens of smart cities, an aspect crucial yet underexplored in the context of renewable energy technologies. Methods/Analysis: A comprehensive survey was conducted involving 560 respondents to assess public perceptions, attitudes, and behaviors toward solar PV systems. The study also examined the moderating effects of area (urban/rural), gender, trust, and duration of use (experience) on societal acceptability. Findings: The results show that both independent and moderating variables significantly influence the social acceptability of solar innovations in smart cities. Key factors identified include the user-friendly design of solar systems, effective awareness campaigns highlighting their benefits, and compatibility with existing technologies. These elements are crucial in fostering positive attitudes and intentions towards the adoption of solar energy. Novelty/Improvement:This research provides valuable insights for policymakers, energy planners, and researchers, emphasizing the importance of considering demographic and experiential factors in policy-making. The findings suggest that societal acceptance of solar PV systems can be enhanced by targeting area-specific needs, leveraging trust, and promoting the benefits of prolonged usage experience. Doi: 10.28991/CEJ-2025-011-02-016 Full Text: PD
Improving Efficiency and Accuracy in Construction Sales Valuation via Random Search Optimization
No full textThe valuation of construction project sales depends on various economic variables and indices. While accurate cost predictions support financial planning and risk management, traditional grid-search optimization-based machine learning techniques often demand extensive computational resources for training and optimization, especially when large datasets require comprehensive machine learning models. Recent investigations highlighted that random search optimization can shorten the training time of ensemble machine learning methods. Nevertheless, its effectiveness for construction project cost valuation, especially when examining model accuracy and training time, is still unclear. This research examines the usability of random search optimization for machine learning models in construction project sales valuation and compares it with the standard grid search approach. A large dataset with 103 inputs from 372 construction projects is used as the basis of the investigation. Six different machine learning models are designed and optimized under grid search and random search approaches to evaluate training time and predictive accuracy. The study results indicate that random search optimization cuts training time by up to 70% and preserves a high level of accuracy, with the best-performing model achieving an R² of 0.98 on the test set. These findings highlight random search optimization as a strong alternative to grid search, providing significant computational savings without harming model performance. The study offers guidance on effective hyperparameter tuning methods that may facilitate scalable and budget-friendly predictive models for construction project valuation
Optimization of Dualistic Reservoir System Two-Dimensional Rule Curve with Three Allocation Rules
No full textA two-dimensional operation chart is commonly used to manage the operation of a dual-reservoir system, where the water storage in each reservoir is accurately considered in the water-supply decision. The dual reservoir chart should be combined with one allocation rule to better represent water supply distribution between reservoirs. In this study, the 2D rule curve was coupled with three allocation rules: variable allocation ratios, fixed allocation ratios, and compensation regulation, to identify the efficiency of using these rules with the 2D rule curve in operating the dual reservoirs. Mosul-Dukan dual reservoirs in Iraq were implemented as a study area using monthly data extended from 2001 to 2020. The Shuffled Complex Evolution Algorithm was used to optimize the water allocation ratios. The results revealed that the variable allocation ratios were superior to the other two rules in terms of water deficit, in which the total water shortage of the variable allocation ratios rule was 56590 Mm3. The total shortage was less than that obtained by the fixed allocation ratio and compensation regulation rules by 0.9% and 56%, respectively. Finally, the variable allocation ratio was more suitable for application with a 2D reservoir rule curve than the two remaining rules (fixed allocation ratio and compensation regulation rules). The variable allocation ratios sustainably manage reservoirs in the regions that suffer from water scarcity and represent the most vulnerable to the impact of climate change. Doi: 10.28991/CEJ-2024-010-02-04 Full Text: PD
Evaluation of Alkali-Activated Mortar Incorporating Combined and Uncombined Fly Ash and GGBS Enhanced with Nano Alumina
No full textThe present research focuses on assessing the fresh and hardened properties as well as the durability performance of alkali-activated mortar in an ambient environment and the impact of integrating nano-alumina (NA) at a 2% ratio as a substitute for binder materials in alkali-activated mortar (AAM). Additionally, it assesses the effectiveness of alkali-activated mortar employing different blends of ground granulated blast furnace slag (GGBS) and fly ash as environmentally friendly substitute building materials. Fly ash (FA), ground granulated blast slag (GGBS), and an equal mixture of GGBS and FA make up these binder ingredients. As a result, the main binders contain GGBS, FA, or a 50/50 mixture of GGBS and FA. The sodium hydroxide (NaOH) concentration is fixed at a 12-molarity level, and the alkali activator solution to binder ratio is kept at 0.5. In the alkali solution, the ratio of sodium silicate to sodium hydroxide is always 2.5. The study evaluates various properties of AAM, such as compressive strength, flowability, unit weight, flexural tensile strength, and durability, under ambient conditions at a steady room temperature of 23±3°C. Results indicate that AAM mixtures devoid of NA exhibit a higher flow rate compared to those containing NA. Nonetheless, the flowability of AAM mixtures aligns well with standard requirements, being modest yet adequate. Significantly, the inclusion of NA enhances the mechanical properties and durability of AAM, demonstrating its beneficial effects. Doi: 10.28991/CEJ-2024-010-03-016 Full Text: PD