Incorporating fibers into reinforced cement concrete significantly enhances the structural suitability under impact and seismic loads by augmenting the stiffness and energy-saving efficiency of the material. Concrete cracks activate the vital fiber behavior called the bridge effect, enhancing the structure's strength and ductility. Since adding fibers to the concrete mix does not reduce water content but rather impairs workability due to the friction generated between fibers and the mixed paste, resulting in fiber balling. This phenomenon diminishes the performance of fiber-reinforced concrete. Adequate distribution and dispersion of fiber in the mix increases the strength and thus avoids the occurrence of fiber balling. According to reviews, nylon fiber dosages ranging from 1.5% to 3% result in effectively performing nylon fiber-reinforced concrete, which exhibits sufficient strength, durability, and flexibility. In this study, experiments have been conducted to better understand the behavior of nylon fiber-reinforced concrete at elevated temperatures by using 17 mm, 25 mm, and 50 mm nylon fiber at 1.5% and 3% dosages. When comparing different temperatures, such as normal temperature condition and elevated temperature conditions (400 °C and 800 °C), always 1.5% dosage has shown the best result for compressive strength and split tensile strength. Here, 3% dosage of nylon fiber has shown reduced mechanical strength because of the effect of fiber balling. As far as compressive strength has taken into account in three temperature cases (normal temperature, 400 °C and 800 °C), 1.5% dosage and 50 mm length of nylon fiber has achieved the most effective strength result. Besides, when split tensile strength has been concerned, 1.5% dosage and 25 mm length of nylon fiber have given the best result compared to other lengths and dosage in three temperature conditions.
This study investigates the sustainability and performance of M20 and M30 grade concrete incorporating Ground Granulated Blast Furnace Slag (GGBFS) and Pond Ash as partial replacements for Ordinary Portland Cement (OPC) and fine aggregates, respectively. Replacement levels were varied between 10% and 50%, and their effects on workability, strength, and durability were analyzed using Multiple Linear Regression (MLR) and Principal Component Analysis (PCA). Concrete mixes with up to 40% replacement demonstrated enhanced workability (R² = 99.96%, MAPE = 0.85%), attributed to improved particle packing and reduced internal friction. However, beyond this threshold, workability declined due to increased porosity and water absorption. Compressive strength (CS), flexural strength (FS), and split tensile strength (SPT) showed a diminishing trend with higher replacement levels. Model for compressive strength achieved an R² of 97.21% and MAPE of 3.21%, while flexural strength model had an R² of 99.68% and MAPE of 1.13%, indicating high predictive accuracy. Durability assessments revealed a decline in water absorption ( R² = 88.05%, MAPE = 5.45%) and acid attack resistance (R² = 99.83%, MAPE = 0.58%) with increasing GGBFS and Pond Ash content, primarily due to increased porosity and altered microstructural characteristics. Microstructural analysis confirmed reduced hydration density and weaker bond formation at higher replacement levels. Economically and environmentally, the use of GGBFS and Pond Ash reduces carbon emissions and reliance on natural resources, providing cost-effective and sustainable alternatives for concrete production. The findings highlight that optimal replacement levels (up to 40%) achieve a balance between sustainability and mechanical performance, contributing to sustainable development in construction.
Recycled aggregates have gained popularity in the recent decade. In this paper, central composite design and response surface methodology as an analytical approach were implemented to determine experimental design and prepare models of concrete properties made by recycled aggregates in the lab. Three important factors were chosen: the compressive strength (fc) of parent concretes, the rate of substitution of parent concretes, and the amount of cement. In contrast, compressive strength (fc), tensile strength (ft), and water absorption of recycled concrete were considered target responses. Statistical analyses reveal that models were acceptable with R2 values. Both statistical and experimental studies represent that fc, ft, and water absorption of concrete mainly relied on fc of parent concretes. The increase in the fc of parent concretes from 19 MPa to 36 MPa led to the rise in the fc of new concretes from 27 MPa to 38 MPa. In addition, when the substitution rate changed from 8% to 92%, fc of concretes changed from 26 MPa to 30 MPa. Recycled concretes with higher strength could be generated if the fc of parent concrete is high enough, mainly because of the better bond between paste and aggregates. The optimization of multiple responses reveals that a high percentage of parent concretes with high fc could be used in concrete mixtures without a considerable fall in mechanical properties.
The state of bridges in Indonesia is concerning, with only 1.2% of the 18,990 national bridges classified as being in good condition. A significant number of bridge failures stem from inadequate maintenance, highlighting the urgent need for a structured and effective quality management approach. This research develops a Work Breakdown Structure (WBS)-based Quality Management System (QMS) framework specifically for concrete bridge maintenance to enhance performance and ensure adherence to national standards. The QMS encompasses three main stages—inspection, maintenance, and rehabilitation—comprising 10 activities systematically aligned with bridge maintenance requirements. Quantitative findings from expert validation showed high suitability of the QMS framework, with average scores of 4.0 to 5.0 across content, format, and performance effectiveness. Statistical analysis with 33 respondents revealed a strong positive correlation (r = 0.768) between the QMS and key maintenance performance indicators such as structural safety and bridge importance, explaining 54.9% and 59.9% of the variance, respectively. Qualitative insights emphasized the enhanced organization and durability of maintenance processes, supported by 10 Standard Operating Procedures (SOPs), work instructions, and checklists. This study's novelty lies in integrating WBS into QMS for concrete bridge maintenance, providing a structured methodology for achieving consistent and high-quality outcomes. The implementation of this framework is anticipated to significantly improve the safety, reliability, and sustainability of bridge infrastructure in Indonesia.
The utilization of composite castellated beams in structures is common due to the increased bending strength and stiffness of the beam. However, the presence of openings in castellated beams reduces their shear strength. The increased bending strength allows these beams to be used over longer spans; however, the reduced shear strength makes shear force effects more pronounced in such beams. In this study, a comparative analysis of the behaviors of composite beams with castellated and solid-web has been conducted using finite element method. Nine composite castellated beams and nine solid-web composite beams, both with equal heights and cross-sectional areas, were modeled based on castellated configurations. The AISC Design Guide 31 (DG31) provides a method for calculating the ultimate bending capacity of composite castellated beams but neglects the contribution of the upper T-shaped section of the castellated beam. In this study, the focus is on innovatively comparing the load-carrying capacity of composite castellated beams with the AISC DG31 results, highlighting how finite element analysis reveals higher capacities than those predicted by DG31 by 17% to 31% across specimens. It is observed that the load-carrying capacity of castellated specimens is 2% to 5% lower than that of specimens with solid-webs. This difference may increase up to 22% with local failure in the web-post if the first openings of the beam are placed too close to the supports. Notably, the research demonstrates that the web openings in castellated beams have a minor effect on load-carrying capacity, suggesting that despite reduced shear strength, these openings do not significantly impact the overall capacity, particularly when placed thoughtfully in structural design.
Using recycled asphalt pavement (RAP) in asphalt mixtures is common for improving sustainability, but it can lower performance because of the aging and hardening of RAP binder. Aged RAP is stiffer, less flexible, and more prone to cracking. The performance decreases with the age of RAP. Adding materials like nano-materials can help reduce these issues. This study investigates the combined impact of RAP content, RAP age, and Nano-silica (SiO₂) on asphalt performance, focusing on fracture resistance, fatigue resistance, and moisture susceptibility. Asphalt mixtures with 25%, 50%, and 75% RAP were tested using two types of RAPs with different ages (5 and 10 years). Nano-SiO₂ was added in varying percentages (0%, 1%, 1.5%, and 2%) to evaluate its effects. The performance was assessed using the semi-circular bending test for fracture resistance, the indirect tensile fatigue test for fatigue resistance, and the tensile strength ratio (TSR) test for moisture susceptibility. Results showed that Nano-SiO₂ improved the fracture and fatigue resistance of mixtures, especially those with lower RAP content. At 25% RAP, the addition of 1.5% and 2% Nano-SiO₂ enhanced fracture and fatigue resistance by 15-20%. For mixtures with 50% and 75% RAP, Nano-SiO₂ led to significant improvements, with the best results seen at 2% nano-silica. Nano-SiO₂ also enhanced moisture resistance, increasing TSR values above the 80% threshold. Nano-silica mitigated the effects of aging, particularly in mixtures with higher RAP content. According to this comprehensive evaluation, it is recommended to use 25-50% of RAP using 1.5% of Nano-SiO₂ to achieve high-performance mixtures.
This study investigates the influence of aggregate quality on the mechanical properties of concrete samples, utilizing a comprehensive analysis of aggregates sourced from 46 different batching plants across Lorestan Province. The quality assessment of these aggregates was conducted through several tests, including the sand equivalent test, sieve analysis, fineness modulus, and flakiness index. Following this initial evaluation, compressive strength tests were performed on a range of mix designs to identify the most suitable aggregate type for further experimentation. Subsequently, eigth optimized mix designs were developed, encompassing normal concrete, self-compacting concrete, and high-performance cementitious concrete reinforced with steel fibers. The mechanical properties of these selected mix designs were thoroughly evaluated, focusing on compressive strength, splitting tensile strength, and flexural strength. Results demonstrated that the high-performance cementitious concrete, particularly those incorporating steel fibers, exhibited superior mechanical properties compared to the other mix designs. This study underscores the critical role of aggregate quality in enhancing the mechanical performance of concrete, providing insights that can inform future concrete mix design practices. Also, the comparison between results shows that adding fibers can increase the flexural and splitting strength of specimens by up to 47% and 43%, respectively.
A porous asphalt mixture (PAM) is distinguished by its different porous structures, which allow water to move through it as quickly as possible, making drainage an essential component. Porous asphalt pavement (PAP) can maintain its permeability because the mixture contains voids that are interconnected with one another. Permeability, on the other hand, decreases as the proportion of particles in the gradation and the level of compaction increases. To generate various air-void structures, permeability was evaluated with specimens made from varying sizes and shapes of aggregates. The equipment that was used for this research was specifically designed. When compared directly with permeability, the findings indicate that the combination of multiple forms is not directly comparable. The permeability of PAM was observed to be affected by a variety of air void densities, which were observed. While there was a beneficial influence on permeability, there was a negative impact on the Resilient Modulus (MR), which was detected when there was an increase in the void content. The amount of air voids in the mixture substantially impacts the performance of porous asphalt mixtures. Open-Gr-I viscosity grade (VG30) bitumen has a permeability value of 0.394 cm/s, and the resilience modulus value for open-Gr-II mixtures that use a modified binder is 3494 MPa. Both of these values are relative to the permeability value. The drainage and stiffness metrics for the several combinations investigated in this study were considerably impacted by the gradation, the kind of binder, and the temperature conditions. Stormwater management is possible in PAP and improves the groundwater table.
Bottles made with polyethylene terephthalate (PET) will never biodegrade. These are banned due to their adverse effect on the environment. The prohibition of plastic extends to items like plastic cups, plates, and packaging, in addition to plastic bags. At this juncture, Recycling or reusing plastic waste is crucial to protect the environment. Hence, it is decided to reuse the PET bottles in this research work. In this research, it is decided to reuse the PET bottles by cutting them into 20 mm wide strips and wrapping them around the steel bar in such a way that both behave monolithically as a part of the reinforcement in the reinforced concrete element. It is proposed to do an experimental investigation by conducting a flexural test on the beams. Cast using a single plastic strip wrapped partially around the 8 mm diameter steel bar located in the tension zone and also using a double wrap partially around the 8 mm diameter steel bar located in the tension zone. The findings are to be compared with the conventional concrete beam and the PET-wrapped beam has gone under nearly 18% higher deflection than the conventional beam. And, also the double-strip wrapped beam undergoes deflection of up to 5% higher than the single-wrapped beam under the same load.
Fiber Reinforced Polymer (FRP) composites are commonly utilized for retrofitting concrete members. While this retrofitting approach offers numerous advantages, some challenges remain. Pre-stressing the FRP is a promising strategy to optimize the proficiency of this method by enhancing the effectiveness of the composite and delaying debonding failures. However, conventional pre-stressing methods require specialized equipment and anchorage solutions. This research introduces a device explicitly designed for pre-stressing FRP composites used in retrofitting of concrete beams and slabs. Eliminating the demand for hydraulic jacks, straightforward operation, and being lightweight are among the critical advantages of the device. Furthermore, the device’s dimensions and weight are adjustable to take into account various composite sizes, and desired pre-stress levels, ensuring economic and practical feasibility. This study details the design and construction of the device, followed by an evaluation of its performance in pre-stressing carbon fiber reinforced polymers (CFRP) for retrofitting reinforced concrete T-beams via experimental tests. The results showed the potential of the proposed device for utilization in retrofitting applications. Also, a finite element model of the device and the associated analysis methodology are presented.
Landfill liners are critical components of waste management infrastructure, designed to prevent the migration of leachate into the surrounding environment. However, the long-term performance of these liners is significantly influenced by their susceptibility to desiccation cracking. This study investigated the effectiveness of incorporating polypropylene composites, micro-silica, and nano-silica as additives within the clay liner material to mitigate cracking and enhance overall liner performance. Three distinct clay types were evaluated: local soil, soil excavated from the landfill site, and a synthetic clay mixture. Laboratory experiments were conducted to assess the impact of the additives on crack formation and by extension, the hydraulic conductivity of the liner material. The results demonstrated a significant reduction in crack formation across all clay types with the addition of 0.8% polypropylene. Similarly, incorporating 20% micro-silica exhibited a marked decrease in cracking, suggesting a potential improvement in the long-term hydraulic performance of the liner. These findings indicate that the inclusion of these additives can enhance the resistance of the clay liner to desiccation, thereby minimizing the risk of leachate migration and contributing to the environmental integrity of the landfill site. This research has important implications for the design and construction of more robust and environmentally sound landfill liners. Further research is warranted to optimize the concentration and combination of these additives, evaluate their long-term performance under field conditions, and assess their cost-effectiveness in improving the overall durability and environmental performance of landfill liners.
This study investigates the behavior of steel moment-resisting frames under fire conditions, focusing on the structural response of three- and nine-story frames exposed to high temperatures. The analysis evaluates the effects of elevated temperatures on deflections, internal forces, and inter-story drifts. Various fire scenarios are considered, with a fire duration of 120 minutes and a maximum temperature of 1050°C. The results reveal significant inter-story drifts, deflections in mid span of beams and substantial changes in internal forces of beams and columns. The columns are highly susceptible to buckling due to thermal expansion and reduced material properties. The results highlight the importance of focusing on columns and lower-to-mid-level stories in fire safety evaluations, as these components are more prone to failure and can significantly influence the overall structural stability. The strengths of this study lie in its thorough analysis of multiple fire scenarios and its precise identification of critical failure points, offering a robust foundation for advancing fire-resistant design methodologies. These findings have significant practical implications, as they provide engineers with valuable insights for enhancing the safety and performance of steel moment-resisting frames under fire conditions.
The use of reinforced concrete (RC) deep beams has expanded dramatically over the past few decades. Then, improving the performance while maintaining the cost as low as possible cost has become a critical concern. In the current work, a layered model based on using high performance concrete (HPC) at the top half of the section only has been considered. Six specimens were tested experimentally under static load up to failure. It is aimed to determine the range of improvement in the general performance due to use of steel fiber concrete (SFC) or reactive power concrete (RPC) at the top half of the deep beams. Moreover, the effect of loading configuration (one-point or two points) which considered implicitly the effect of the shear span-to- depth ratio (a/h) was considered. The response was studied in terms of several indicators including the load-deflection curve, the failure load the crack width, the mode of failure, map of cracking, toughness, and ductility. Results showed that for one-point load, the failure loads for the hybrid specimens with SFC and RPC at top layers of the section was enhanced by 22% and 28% relative to the non-hybrid model. While enhancements of 27% and 34% were recorded under two point loads. Moreover, it was found that reducing a/d ration from 1.67 to 1.22 resulted in enhancements of 32%, 37% and 39% for the non-hybrid and hybrid sections respectively. Regarding toughness, enhancements of 28% and 144%, were obtained for the specimens hybrid with SFC under one-point and two-point loading systems respectively. When RPC was used, the corresponding improvements were 44% and 188%, respectively.
Given its location along the equator, Indonesia has a tropical climate with two rainy and dry seasons. The significant variations in temperature that each season brings about are important factors when building civil engineering projects, including rigid pavements, to ensure their long-term performance and durability. Currently, rigid pavement design regulations exclude considering the influence of temperature variations. The dowels enormously affect how the rigid pavement system works overall, and joints typically represent the weakest sections in the structure. This study investigates the effects of temperature variations on the stress-strain characteristics of rigid pavements, focusing mainly on dowel behavior. The investigation was conducted through simulation modeling in Abaqus software, incorporating solid 3D elements—specifically hexahedral and tetrahedral types—with materials modeled as homogeneous, isotropic, and linear-elastic. The results indicate that heat conduction in rigid concrete slabs follows a linear pattern, generating tensile stress on the dowels (Sxx=1.719 MPa) and maximum shear stress (Sxy=1.754 MPa), both of which remain below the material’s yield stress. The displacement of the dowels varies depending on whether the dowels are fixed or free. Fixed dowels move with the concrete slabs, resulting in lower displacement than free dowels. Thermal loads applied to the upper surface of the rigid pavement led to increased stress and displacement as the temperature rises.
3D Printed Concrete (3DPC), or additive manufacturing in construction (AMC), is rapidly transforming the construction industry. By offering enhanced automation, faster construction processes, and reduced labor costs, 3DPC minimizes material waste and enables intricate architectural designs that are not feasible with traditional methods. A comprehensive review spanning 2013–2023 confirms its viability, particularly in remote or challenging environments where conventional construction faces limitations. This technology eliminates traditional formwork, granting unprecedented design flexibility and enabling the creation of complex geometric shapes. The review highlights recent advancements in 3DPC while acknowledging challenges hindering widespread adoption, including high initial costs, the need for rigorous pre-fabrication structural modeling, and complex regulatory approvals. Conducting cost-benefit analyses is critical for broader industry acceptance. The study emphasizes 3DPC’s sustainability potential, particularly in reducing environmental impacts. Recognizing the ecological drawbacks of Portland cement, 3DPC offers a pathway to reduce cement consumption and mitigate the construction industry’s carbon footprint. Strategies to optimize energy and environmental performance include exploring alternative cementitious materials (e.g., geopolymers, recycled aggregates) and refining printing processes to minimize waste. Furthermore, the research examines 3DPC’s socio-economic implications, such as job creation in advanced manufacturing and localized production benefits. Despite challenges like regulatory complexity and upfront investment, 3DPC represents a promising avenue for a more sustainable, efficient, and innovative future in construction.
The main objective of this study is to evaluate the mechanical properties of geopolymer concrete (GPC), made from alkaline-activated fly ash and Ground Granulated Blast Furnace Slag (GGBS), compared to conventional M30 grade concrete. Additional samples of GPC incorporating steel fibers were also tested. To investigate the behavior of these materials under elevated temperatures (0°C, 250°C, 500°C, 750°C), thirty-six specimens were cast and tested, including cubes, cylinders, and prisms. These specimens comprised slag-based GPC (containing GGBS and fly ash) and standard M30 concrete. The results of the compressive strength tests indicated that GPC demonstrated 22.3% greater strength than conventional concrete. Furthermore, adding steel fibers to GPC enhanced its compressive strength by 61%. The split tensile strength of GPC was 71.8% higher than standard concrete, and GPC with steel fibers exhibited a 118.5% increase. Similarly, the flexural strength (modulus of rupture) increased by 22% for GPC and 54% for GPC reinforced with steel fibers, compared to conventional concrete. Overall, the findings reveal that incorporating steel fibers significantly improves the mechanical properties of slag-based GPC, particularly in compressive, tensile, and flexural strength, making it superior to ordinary Portland cement (OPC)-based concrete.
The base isolation method is being utilized for more than two decades as a way to protect structures. Despite recent advancements in the seismic evaluation of isolated structures, the impact of ductility level on based-isolated Reinforced Concrete (RC) moment-resisting frame structures has not been explored. In order to consider the effect of ductility level, the present paper evaluates the seismic behavior of isolated RC moment-resisting frames through Double Friction Pendulum Bearings (DFPB) with ordinary, intermediate, and special ductility. Additionally, we compared responses of these systems with the similar conventional structures. To this end, three RC moment-resisting frame structures were designed with/without DFPB, and three-dimensional (3D) models were implemented in OpenSees. Then, seismic responses of these six models, including peak floor absolute acceleration, base shear, plastic rotation, and story drift of column were evaluated. According to the results. Ductility levels have a significant impact on the fixed and isolated structures. As a result of the special moment-resisting frame superstructure, plastic rotation and peak drift demand of columns is increased compared to the ordinary and intermediate ones. The maximum differences in plastic rotation and peak drift demand between ordinary and special frames were obtained as approximately 70% and 50% in base-isolated buildings.
Sustainability of building materials in construction requires minimal or no waste, which entails the reuse/recycling of construction waste materials (CWM). The construction industry generates a significant portion of solid waste across the globe. This study is aimed at identifying the potential benefits and challenges of CWM reuse/recycling in order to proffer sustainable strategies for overcoming obstacles to optimal reuse/recycling of CWM. Descriptive survey design and desk study were employed in this research. Purposive sampling techniques were used to gather data for the study, using Nigeria as a study area. Data obtained from the study were analyzed using descriptive analysis. Lack of recycling facilities with a score of 83.8% was identified as the biggest hindrance to the optimal reuse/recycling of CWM. Establishment of local recycling centers having a score of 77.1% was recognized as the most effective strategy for solving the challenges of optimal reuse/recycling of CWM. Government/government agencies/parastatals having the score of 76.5% were identified as the major key players in CWM reuse/recycling. Recommended strategies for best practices in the reuse/recycling of CWM include policy and regulations, planning, incentives, and the establishment of local recycling centers. With potential applications in other developing countries, this research offers a ground-breaking framework for encouraging sustainable construction practices and reducing construction waste in Nigeria.
Falling Weight Deflectometer (FWD) can evaluate the assessment of structural conditions of pavements that require rehabilitation. Fifteen different pavement sections have been selected that six sections have located in Qom-Kashan Freeway, Iran and nine sections have located in Kashan-Qom Freeway, Iran to conduct FWD tests. FWD data have been analyzed to determine and monitor the structural adequacies of existing pavement sections includes the pavement deflection and load chart, the average deflection chart of seven geophones, and the calculated overlay thickness diagram for each station of each section. The results indicate that the average deflection for Direction: Qom-Kashan, is 6.7% less than Direction: Kashan-Qom. In this paper, the structural conditions of existing pavements have been assessed, and subsequently required overlay thickness values have been recommended from critical pavement responses computed from FWD field deflections. The results indicate that the surface of the pavement for Direction: Kashan-Qom needs 6.1% more overlay thickness than Direction: Qom-Kashan. Also, the Structural Condition Index (SCI) that is widely used on network and preliminary project level investigations has been calculated. Furthermore, a comparison is presented between calculated SCI before and after applying overlay and the effect of this index value on the pavement performance.
Construction is an ever-growing industry that significantly contributes to the global economy and provides infrastructure for many diversified sectors such as housing, transportation, water supply, irrigation, and many other projects. The construction of these projects leads to increased demand for conventional materials in the form of bricks, cement, steel, aggregates, and so on, which has adversely impacted the environment. It has become inevitable for construction professionals to look for energy-efficient sustainable alternatives for conventional building materials. In the present experimental work, the authors have used construction waste as a sustainable alternative by replacing conventional materials partially or completely in masonry units. Construction wastes collected from nearby dump yards are segregated and processed to get the recycled aggregates which are later tested for quality. These aggregates and binders are proportioned to cast stabilized blocks having different engineering properties. These blocks when tested in compression at 7,14 and 28 days, have resulted in strengths in the range of 2.82 MPa to 6.82 MPa. The blocks exhibiting higher strengths were further tested for physical, mechanical, and durability properties namely dimension, density, water absorption, scratch, and efflorescence. In addition, these blocks and the basic materials are tested for their microanalysis through SEM, XRD, and FTIR. Finally, prisms are cast and tested as a masonry unit at 7,14, and 28 days. These blocks showed a maximum dry compressive strength of 4.1 MPa. From the study, it is observed that the stabilized recycled aggregate with 10% cement binder has resulted in acceptable alternative blocks having good engineering properties. The same is presented in the graphical abstract as well.
