Challenge Journal of Concrete Research Letters
cjcrl.challengejournal.com Challenge Journal of Concrete Research Letters is an international, quarterly published and open access scholarly journal that publishes original research articles as well as short communications, review articles, case studies, discussions, book reviews and letters to the editor in all areas of concrete research. Challenge Journal of Concrete Research Letters (CJCRL) -formerly known as Concrete Research Letters- publishes as rapidly as possible manuscripts of high quality which addresses eminent topics related to concrete performance, production, durability, sustainability and applications. Being an international, peer-reviewed, online and open-access journal, CJCRL presents a world-wide forum for the dissemination of knowledge among engineers, scientists and mathematicians working in the field of concrete.
Evolutionary process and mechanical properties of polymers: A comprehensive review
The growing demand for innovative construction materials has driven the exploration of polymer-based composites due to their enhanced mechanical performance and potential environmental benefits. However, a clear understanding of the historical development, classification, and structural behavior of polymers in construction remains limited. This review aims to bridge this gap by synthesizing current knowledge on the historical evolution, mechanical benefits, chemical benefits, drawbacks and real world applications of polymers in construction. The study focuses on key thermosetting resins such as polyester, epoxy, vinyl ester, and PET and assesses their mechanical properties relevant to structural applications. To address the lack of integrated insight in the literature, the review compiles and compares data from various primary sources. Mechanical properties such as tensile, compressive, and flexural strength are evaluated to determine the suitability of each polymer for construction use. The outcomes indicate that epoxy resins demonstrate superior tensile and flexural strength, while polyester and polyethylene terephthalate PET offer notable advantages in compressive resistance and sustainability. Overall, the findings provide a consolidated understanding of polymer development and performance, offering valuable guidance for researchers and engineers aiming to enhance material efficiency, durability, and environmental responsibility in the construction industry.
Copyright (c) 2025 by the Authors. This is an open access article distributed under the CC BY licence. http://creativecommons.org/licenses/by/4.0
Compressive strength and fire resistance of mortar containing spent garnet as partial sand replacement
The increasing demand for sand in construction, driven by rapid urbanization, has led to unsustainable sand mining and significant environmental degradation. This study addresses the urgent need for sustainable alternatives by investigating the use of spent garnet, a waste by-product from abrasive blasting, as a partial replacement for fine aggregate in mortar. Despite its widespread disposal in landfills, spent garnet has potential as a viable substitute due to its high bulk density and angular particle structure. This research explores the effects of substituting sand with spent garnet at 10%, 20%, 30%, and 40% replacement levels. The novelty of this study lies in its integrated evaluation of workability, mechanical strength, and thermal resistance of mortar incorporating spent garnet. Results from flow table tests showed a progressive increase in flowability, with the 40% garnet mix achieving a maximum flow of 142%, compared to 68.3% for the control mix. Density increased from 4958 kg/m³ (0% garnet) to 5180 kg/m³ (40% garnet), enhancing packing efficiency. The highest compressive strength was recorded in the 20% replacement mix, with values of 37.95 MPa at 7 days and 50.99 MPa at 28 days, an increase of 12.5% and 42.3%, respectively, over the control mix. Thermal analysis revealed the lowest mass loss in 10% and 20% replacement mixes, with the 20% mix also showing improved fire resistance. These findings indicate that a 20% spent garnet replacement offers the optimal balance between workability, mechanical performance, and thermal stability. This approach not only enhances mortar properties but also promotes sustainable waste management and reduces reliance on natural river sand.
Predicting compressive strength of heavyweight concrete using deep neural networks and Box–Behnken design
This study investigates the prediction and evaluation of compressive strength in heavyweight concrete incorporating magnetite and steel slag, using two advanced modeling techniques: Deep Artificial Neural Networks (DANN) and Box-Behnken Response Surface Methodology (BBRSM). A total of 324 concrete specimens were prepared based on 36 unique mix designs. Non-destructive testing methods ultrasonic pulse velocity (UPV) and Schmidt rebound hammer (SRH) were employed to characterize material properties. The 28-day compressive strength of each sample was determined following ASTM C39 standards. Data from UPV and SRH tests, along with mix parameters such as the water-cement ratio, were used as inputs for both models. The DANN model, developed using a hybrid architecture combining Convolutional Neural Network (CNN) and Long Short-Term Memory (LSTM), achieved superior predictive performance, with a coefficient of determination (R²) of 0.9951 and a root mean square error (RMSE) of 0.0314 MPa. This corresponds to a coefficient of variation of just 0.045%, with a standard deviation error of 0.02% relative to the mean compressive strength of approximately 70 MPa. In contrast, the BBRSM model, employing a sixth-degree polynomial equation, yielded an R² of 0.9628 and a standard deviation of residuals of 1.36 MPa (about 1.94% of the average strength). The findings highlight the enhanced accuracy and efficiency of the Hybrid DANN model over the BBRSM approach. While both techniques offer practical, cost-effective alternatives to experimental testing, the DANN model is particularly well-suited for capturing complex nonlinear behaviors, whereas BBRSM remains valuable for optimization-oriented analysis.
A novel neuro genetic programming framework for modelling compressive strength of recycled aggregate concrete
Recycled Aggregate Concrete (RAC) can represent as a sustainable alternative to conventional concrete; however compressive strength prediction of RAC is difficult due to the complex and nonlinear interactions between the materials in the mix. Researchers have been utilizing soft computing tools like: Genetic Programming (GP), Artificial Neural Network (ANN) etc. for predicting compressive strength, however the performance of these models is satisfactory. To leverage the characteristic of evolutionary optimization in Multi Gene Genetic Programming (MGGP): variant of GP and the effective nonlinear input and output mapping through ANN, the present study introduces a Novel Neuro Genetic Programming framework (NMGGP), an advanced hybrid approach that combines the strengths of MGGP and ANN. The NMGGP framework is a framework devised in three phases: (i) MGGP constructs a multigene model, where each gene represents a weighted mathematical expression derived from input parameters; (ii) High-weighted genes, are selected, and transformed into transformed inputs to enhance the learning process. (iii) These transformed inputs, along with the original output, are fed into an ANN enabling advanced nonlinear mapping and precision in prediction. The proposed model was tested for predicting the 28-day compressive strength of RAC which considered 8 inputs as the kg/m3 quantity of concrete mix. Further three highly weighted genes were transformed into transformed inputs and predictions were done in phase III. The results displayed an excellent model with r=0.967, RMSE as 4.744 and MAE as 3.944 as compared to the stand-alone models of MGGP and ANN with r=0.930, RMSE more than 5.0 and MAE mode than 5.0. The results also can be said to be robust through a balanced scatter plot and graphical comparison between predicted and observed 28-day strength of RAC.
Experimental performance analysis of concrete-filled steel column to concrete-filled steel beam connections
Existing literature and practical engineering practice have comprehensively examined the behaviour of concrete-filled steel tubular (CFST) columns, CFST beams, and their associated connection systems involving either steel or reinforced concrete (RC) beams. Despite these advancements, limited research has focused on the direct beam–column interaction in fully CFST-to-CFST connection configurations. The absence of established design specifications and systematic experimental evidence has hindered the reliable adoption of such connections in structural applications. This feasibility study addresses this knowledge gap by conducting an integrated theoretical and experimental investigation into the structural performance of moment-resisting connections between CFST columns—locally strengthened with internal stiffening plates and configured with external bolted flange connections—and CFST beams of matching geometry. To provide a meaningful benchmark, a comparable hollow steel column–steel beam connection with identical cross-sectional dimensions and bolt arrangements was also evaluated. The experimental setup involved cyclic loading tests designed to capture load–rotation behaviour, quantify flexural stiffness, and identify critical limit states governing connection performance. Detailed measurements of moment–displacement response, local deformation patterns, and strain distribution were collected to assess connection rigidity, load-transfer mechanisms, and potential vulnerability to local buckling. The resulting data allowed for direct comparison between the proposed CFST-to-CFST connection configuration and the hollow steel reference specimen, enabling a clearer understanding of the composite action and confinement effects provided by the infilled concrete. The findings contribute foundational evidence for the feasibility of those moment connections and offer preliminary insights to support future analytical modelling, design recommendations, and full-scale implementation.
Design of reactive powder concrete mortar mixes through high strength and durability
This research investigates the characteristics of reactive powder concrete (RPC) through comprehensive analysis. The primary methodology involved evaluating both fresh (uncured) and hardened RPC specimens. The initial phase incorporated silica fume (SF) as a cement replacement at concentrations of 5, 10, 15, 20, and 25%, fly ash (FA) substitution at levels of 5, 10, 20, 25, and 30% of the cement content, plus binary combinations where SF constituted 10% cement replacement while FA proportions ranged from 10 to 30%. Material behavior was assessed through slump flow testing procedures. Hardened concrete evaluation encompassed dry density measurements, compressive strength analysis conducted at 7, 28, 56, and 90-day intervals, along with tensile splitting strength and flexural strength determination at 28 days. Results demonstrate that FA substitution alone provides superior workability compared to SF+FA combinations and pure SF, whereas SF replacement individually exhibits enhanced compressive, tensile splitting, and flexural strength performance relative to standalone FA and binary SF+FA mixtures. The subsequent investigation phase examined the influence of nano-silica (NS) on fresh and hardened RPC characteristics. NS replaced cement at 1, 2, 3, 4, and 5% levels, combined with 10% SF and 20% FA. Findings revealed that increased NS content diminishes workability due to elevated water demand for hydration and mixing processes as particle fineness increases. Regarding hardened properties, the optimal composition comprises 10% SF, 20% FA, and 3% NS, attributed to NS’s effective interaction with calcium hydroxide generated during cement hydration, which facilitates additional C-S-H formation through enhanced pozzolanic reactions. This mechanism results in improved mixture performance and strength development.
Experimental study on the mechanical performance of polypropylene fiber-reinforced concrete incorporating palm oil fuel ash as partial cement replacement
Environmental pollution caused by the disposal of palm oil fuel ash, a type of waste from the palm oil trade, needs to be resolved. At the same time, activities involved in the manufacturing of cement, which is the primary binder in commonly used concrete, have undesirable impacts on the environment. In view of environmental sustainability, the approach of using palm oil fuel ash as a pozzolanic material would contribute towards a cleaner, greener environment. The present study aimed to investigate the fresh and mechanical properties of polypropylene fibre-reinforced concrete mixed with palm oil fuel ash as a cement replacement. Six different mixtures were tested with varying weight percentages of palm oil fuel ash as a cement substitute. Water absorption, workability, compressive strength, and splitting tensile strength were among the tests conducted. Concrete loses some of its workability when palm oil fuel ash is added. The strength of the concrete increases upon incorporating 10% palm oil fuel ash, benefiting from the pozzolanic reaction, which forms a compact internal structure. Notably, at this optimal level, compressive strength improved by approximately 9.5% compared to the control mix after 28 days of curing. This study provides new insights into the underexplored area of incorporating POFA in polypropylene fibre-reinforced concrete (PFRC), where limited prior research exists, thus expanding the understanding of sustainable composite materials. The utilization of palm oil fuel waste for concrete production contributes to the development of environmentally friendly construction materials and supports sustainable building practices.
Predictive modelling of acoustic emission signal data for corrosion assessment: A modified dimensional analysis based approach
Acoustic emission (AE) technique has been proved as a powerful technique for structural health monitoring. AE technique can also be efficiently used for evaluation of corrosion activity in concrete. Despite its advantages, an effective analysis of data recorded by AE technique still founds to be a challenging task demanding an appropriate damage assessment methodology. For quantification of damages, various methods for analysis of AE data have been proposed but not a single method has found to be standardized for specific application. In this paper, a procedure for analysis of AE signals is proposed using modified dimensional analysis method. Many times, it becomes difficult to choose the appropriate AE parameter which can be effectively co-related to the physical feature for development of accurate prediction model. Hence, in the present research work an attempt has been made to develop a model by incorporating primary characteristic AE waveform parameters. A corrosion rate prediction model using modified dimensional analysis of AE signals is developed and compared with the model developed using non-linear regression analysis. The performance of two models is further assessed using different statistical parameters. The study demonstrated that the methodology of modified dimensional analysis indicated improvement in the corrosion rate predictions. Thus, modified dimensional analysis can be implemented as a promising method for analysis of complex AE signal data as well as for development of statistical modelling of corrosion phenomenon in reinforced concrete based on recorded AE parameters.
Copyright (c) 2025 by the Author. This is an open access article distributed under the CC BY licence. http://creativecommons.org/licenses/by/4.0
Impact of wrap quantity on strength of damaged and undamaged CFRP-reinforced structural members
In this study, the effect of carbon fiber reinforced polymer (CFRP) wrapping on the compressive and bending behavior of damaged reinforced concrete structural elements located in high earthquake risk areas was investigated in detail. The main objective was to evaluate the potential of CFRP wraps as an effective strengthening technique for improving the mechanical performance of concrete members that have already sustained damage. During the experimental phase, concrete specimens in the form of 15×15×15 cm cubes and 10×10×50 cm prisms were prepared using CEM IV 32.5 pozzolanic cement, which is commonly used in structural applications due to its durability and environmental benefits. After subjecting these specimens to controlled damage to simulate real-life structural degradation, they were reinforced using single and double layers of CFRP wrapping. The mechanical performances of these wrapped specimens were then assessed through compressive and bending strength tests. The results demonstrated that CFRP wrapping significantly enhanced the compressive strength of the specimens, with double-layer applications showing the greatest improvements. However, the effect on flexural strength was found to be more limited, indicating that although CFRP is 60.83% effective in resisting compressive loads, its contribution to flexural capacity may require additional considerations. Furthermore, double-layer CFRP wrapping not only improved strength but also increased deformation capacity, indicating enhanced ductility and energy absorption. Despite the relatively high cost of CFRP materials, these findings highlight the technique as a practical and efficient solution for the rehabilitation and strengthening of compression load-bearing members, particularly in regions vulnerable to seismic activity.
Exploring deflection challenges: A case study on the influence of heavy concrete weight on profiled steel deck slabs
This paper presents a case study of a deflection challenge in a profiled steel deck slab subjected to heavy concrete loads, as observed during a field investigation. In recent decades, such slabs have gained popularity in both the construction and industrial sectors due to advantages such as being lightweight, cost-effective, quick to install, and capable of resisting natural disasters. However, field observations indicate that when these slabs are subjected to heavy concrete weight, they may experience significant deflection, raising concerns about long-term performance, durability, and serviceability. Excessive deflection can lead to cracking, reduced structural stability, and increased maintenance costs. It is therefore critical to understand the factors influencing deflection by examining key parameters such as material properties, slab geometry, reinforcement detailing, and load distribution characteristics. This study provides a comprehensive assessment of the structural response of such slabs. Field observations suggest that optimizing the L-angle section and C-channel section in areas where the concrete width increases can effectively reduce structural deflection. This approach helps structural elements resist excessive flexural behavior, and when combined with the use of lightweight materials, offers an innovative structural solution that highlights the importance of modern construction practices.
Performance evaluation of compressive strength of concrete using different machine learning algorithms
Accurately predicting the compressive strength of concrete is crucial for ensuring structural integrity, optimizing material usage, and reducing construction costs. Conventional experimental methods, though reliable, are often labour-intensive and time-consuming. To address these limitations, this study investigates the effectiveness of machine learning (ML) algorithms as efficient alternatives for predicting concrete compressive strength. Four ML algorithms—Linear Regression (LR), Multilayer Perceptron (MLP), M5 Rule-Based Model, and Support Vector Machines (SVM)—were evaluated based on their predictive performance. A comprehensive dataset comprising 350 concrete samples was prepared, with compressive strength tests conducted in accordance with Indian standard 516. The models were trained on experimental data and were tested using varying data splits of 50%, 40%, 30%, 20%, and 10% to assess their prediction accuracy. Among the evaluated models, the MLP demonstrated superior performance, achieving a correlation coefficient (CC) of 0.98 with a 20% testing split, outperforming the other algorithms. To further validate the predictive capability of the MLP model, multiple linear regression analysis was employed, confirming its robustness and generalization ability. The findings underscore the potential of machine learning techniques, particularly the MLP model, in providing accurate, reliable, and time-efficient predictions of concrete compressive strength. This study contributes to the growing body of research focused on leveraging machine learning for enhanced decision-making in construction material design, ultimately promoting more sustainable and cost-effective construction practices.
Copyright (c) 2025 Tulpar Academic Publishing http://creativecommons.org/licenses/by/4.0
Effect of dimensions of specimens on the impact performance of concrete
Mechanical properties of concrete are size dependent. While many reports have discussed the size effect of the test specimen on the static properties of concrete, research on the effect of cross-sectional dimensions of the concrete beams on its impact performance is still scarce. This research experimentally evaluates the relationship between the cross-sectional dimensions and orientation of the concrete beam specimens on their impact performance. Repetitive drop-weight test was used to evaluate the impact energy absorption capacity of different concrete beams. A loading protocol to evaluate the impact energy of concrete beams having different cross-sectional dimensions was proposed. The results revealed that the impact performance of concrete is size dependent. Strong proportional relationships between the moment of inertia, cross-sectional area and impact energy were found. As the moment of inertia and cross-sectional area of the test specimen increase, its impact energy exponentially increases. Furthermore, a linear proportional relationship was found between the normalized impact energy and the normalized cross-sectional area × moment of inertia. This means that the impact performance of concrete beams depends on both their cross-sectional area and orientation. The proposed loading protocol has been proven to be able to accurately evaluate the impact energy of concrete specimens with significantly varying impact performance while importantly saving time.
Behavior of multi-cell steel columns under impact loading
This study investigates the behavior of multi-cell steel columns (MCCs) under impact loading through both experimental and numerical analysis. Twelve specimens, including single-cell columns (SCC) and four-cell MCC configurations, were tested in empty and concrete-filled conditions. The specimens were categorized into three groups based on a fixed height-to-width ratio (R). A nonlinear finite element model was developed using ABAQUS and validated against experimental data. Key parameters, including peak deflection, failure modes, deflection-time relationships, maximum impact forces, energy absorption and the rectangularity ratio effect, were examined to provide insights into impact-resistant structural design. The results demonstrate that the internal partitioning of the column into cells significantly reduces local buckling under impact loading by enhancing the section’s local stiffness. In addition, internal partitioning improves energy absorption for empty models. On the other hand, concrete-filled models do not show the same behavior although concrete filling significantly improves resistance to impact forces. The results also provides that increase of the R ratio results in an increase in impact force and a decrease in mid-point displacement. For empty single-cell columns, an increase in R results in a decrease in energy absorption, which may be due to energy dissipation through local buckling under the falling impactor. These findings contribute to the advancement of impact-resistant column designs for applications in structural and transportation engineering.
Tea waste ash: Characterization, pozzolanic activity and effects on the fresh properties of cement pastes
It is a well-known fact that the use of agricultural wastes in cementitious composites by turning them into ash provides both ecological and economic benefits. Tea factories in Türkiye are located in the Eastern Black Sea region. Tea waste generated in factories locally causes environmental problems. This study focuses on the usability of the wastes left over from the products processed in the tea factory. Tea waste from Artvin, Türkiye was turned into ash at 850 °C. Physical, chemical, mineralogical, thermogravimetric and morphological properties of tea waste ash were examined. Pozzolanic activity test was performed to determine its usability in cement systems. Blended cement pastes were prepared by substituting up to 10% tea waste ash. Physical and chemical properties of blended cement pastes were determined. As a result, the tea waste ash was found to contain a high proportion of K2O. The waste material does not show pozzolanic properties. The hydration of cement pastes has accelerated with tea waste ash. Tea waste ash substitution has increased standard consistency water of blended cement pastes. Tea waste ash substitution up to 8% provided the initial setting time included in the standard. It was concluded that tea waste ash could be used as a setting accelerator.
The engineering properties of silica fume and GGBS-based geopolymer mortars cured in elevated temperature
Geopolymer, a promising alternative to traditional portland cement, offers a wide range of sustainable applications in the construction industry. Geopolymer mortar presents a sustainable future by mitigating carbon dioxide emissions associated with cement production. This study aims to investigate the effect of using different minerals admixtures and different curing methods on the engineering properties of geopolymer mortar. The study also investigates the possibility of incorporating geopolymer concrete to develop construction with sustainability features. Five different mixes were prepared by utilizing various mineral admixtures in different ratios of silica fume (SF) and granulated blast furnace slag (GGBS), M20-80 (20% SF and 80% GGBS), M80-20 (80% SF and 20% GGBS), M50-50 (50% SF and 50% GGBS), MS100 (100% GGBS), MSF100 (100% SF). The curing methods for each sample were investigated separately under ambient and oven temperatures (65 °C) for 7 and 28 days to determine the compressive and flexural strength of the samples. The results revealed that the compressive strength value of the mixes MS100, M50-50 and M80-20 in which the curing of ambient method is used show significant increment compared to the same mixes cured in oven temperature. The increment in compressive strength of the ambient curing method was 14.4%, 25.8% and 46.4% for the mixes of MS100, M50-50 and M80-20, compared to the oved curing method, respectively. However, the compressive strength value of the mix of M20-80 and MSF100 cured in oven temperature shows similar compressive strength compared to the ambient temperature curing method.
Concrete strength monitoring and damage detection using piezoelectric-based wireless sensor
Concrete stands as the predominant and extensively employed structural material in civil engineering. Timely evaluation of concrete strength is essential for maintaining structural safety and minimizing construction delays, thereby avoiding possible structural failures. This early check also ensures that concrete structures can bear loads during construction and throughout their service life. A significant challenge in the construction industry is accurately determining the strength of early-age concrete and identifying potential damage without destructive testing. Conventional techniques often require time-consuming procedures and can be impractical for real-time monitoring. To overcome this issue, IoT-based monitoring systems with piezoelectric sensors provide a practical approach for continuous strength monitoring and damage identification in concrete structures. This study utilized a piezoelectric lead zirconate titanate (PZT) sensor, employing a surface-bonding technique to attach the sensor to the cube specimens. The experimental phase spanned four weeks, including intervals of 7th, 14th, and 28th days by standard construction codes to assess necessary strength levels and identify any damage within the structure. This study verified the results obtained by the piezoelectric-based wireless sensor network are practical and reliable. Correlation coefficient values are analyzed to validate the relationship between data from IoT-based testing and compressive strength. All the results are presented in graphical format, confirming that this non-destructive approach can accurately predict concrete strength and identify structural damage. This study uniquely contributed by validating the use of piezoelectric sensors for continuous, in-situ monitoring of concrete, providing a novel approach to early damage detection and evaluating the structural health of the structure.
Mechanical and durability study of nano-SiO2 and nano-TiO2 on fiber reinforced concrete
This work presents the results of an experimental investigation into the strength and durability properties of fiber-reinforced concretes that have polypropylene (PP) fibers added to the concrete by volume and nano-SiO2 (silicon dioxide) and nano-TiO2 (titanium dioxide) used as partial substitutes for cement. Nano-SiO2 and nano-TiO2 particles used ranged in size from 40 nm to 400 nm. The specimens were cast using cement blended nano-SiO2 and nano-TiO2 percentages of 1%, 2%, 3%, and 4% by weight of cement. M55 grade concrete was employed for the casting process. The addition of PP fibers to the concrete was 0.5% by volume. The specimens underwent a battery of mechanical tests, including microstructural testing, compression testing, split tensile strength testing, and rupture modulus testing. Furthermore, tests for durability factors such as porosity, sorptivity, and degradation were conducted, and the findings are presented. Flexural strength of 2% nano-SiO2 or nano-TiO2 increased by 8.09% and 6.89% and porosity decreased by 16.13% and 13.92% with respect to the reference concrete. By comparing the outcomes, it was shown that the inclusion of 0.5% PP fibers and 2% nano-SiO2 or nano-TiO2 improved the mechanical qualities, but this was followed by a decrease in strength. The findings demonstrated that 2% nano-SiO2 combined with 0.5% PP fiber had a greater mechanical strength than 2% nano-TiO2.
Photocatalytic activation of fibrous lightweight polymer concrete surfaces under artificial light source
In general, surface contamination of building materials is caused by pollution, which can be divided into human-made and natural sources. Building materials whose surfaces are exposed to pollutants from these sources for a long time show chemical and physical degradation and lose their function over time and their service life is shortened. Due to photocatalytic feature provided to the material surfaces, organic pollutants on the surface are degraded as a result of oxidation and reduction reactions under the influence of light. In this study, the self-cleaning performance was measured on the surfaces of fibrous lightweight polymer concretes with titanium dioxide (TiO2) reinforcement incorporated into the structure. Perlite-based concrete specimens with TiO2/resin ratios of 0%, 3%, 6% and 9% and fiber/resin ratios of 0%, 0.5% and 1% were prepared. When the results of the self-cleaning test with Rhodamine B dye were examined, the samples with a TiO2/resin ratio of 9% had the highest degradation percentages of about 67%. This study shows that photocatalytic properties can be imparted to lightweight polymer concretes with different structures from conventional concrete by TiO2 reinforcement.
Assessment of stresses and vibration behavior of concrete gravity dam under fluctuating hydrostatic force
Dam structure contributes to the socio-economic development of a country but zero probability of failure of such structure is a design concern. Hence, it is essential to monitor the dam condition under the fluctuating reservoir water and the vibration effect. In this investigation, four different cases of the reservoir depths are adopted to numerically analyze the hydrostatic and modal (free-vibration) behavior of a three-dimensional (3D) gravity dam. The impact of fluctuating reservoir water and uplift pressure on the dam's internal stresses (direct, principal, shear, and Von Mises) are evaluated to examine the location of maximum stress concentration. Under these cases, the maximum displacement along the longitudinal and vertical directions is explored. It can be revealed that case 4 (without tail-water) induces the maximum displacement on the top crest level and the peak normal stress concentrated at the heel region, respectively. This case also experienced the lowest time-period and largest frequency. In comparison to cases 2, 3, and 4, case 1 exhibit the largest crest level displacements along the x-direction that are 26%, 49%, and 86% higher, respectively. Compared to case 1, the normal stresses along the x-direction declined by 51.58%, 68.74%, and 58.25%, respectively for cases 2, 3, and 4. It can be revealed that the frequency is directly related, while the time-period is inversely proportional to the mode-shapes. Overall, this study envisages a comprehensive understanding of the dam’s performance, providing critical data to inform design decisions, safety assessments, and performance improvements.
Flowability and compressive strength of ternary blended cement mortar of coal bottom ash and ground cockle shell ash
Flourishing cement industry to meet the demand of construction industry has negative impact to the global environment owing to the carbon emission during calcination of cement. At the same time, the disposal of coal bottom ash and cockle shell from coal power plant and cockle trade which pollutes the environment also need to be resolved. In view of circular economy, the present research aims to produce ternary blended cement consisting of coal bottom ash (CBA) and cockle shell ash (CSA) for sustainable mortar production. The research was conducted to determine the effect of CBA as partial cement replacement on flowability and compressive strength of CSA blended cement mortar. Seven mortar mixes consisting of CBA as supplementary cementitious material ranging from 0% to 60% by weight of cement were prepared. All specimens were water cured up to 56 days. The flowability test was conducted to assess the properties of the fresh state, while hardened properties were evaluated through compressive strength test at 1, 3, 7, 28, and 56 days. The results showed flowability decreased by 5% to 31% with increasing CBA content compared to the control mix. The use finer sized CBA forms a slightly stickier mortar mix with lower flowability. A combination 10% to 20% CBA is the best percentage to use for formation of CSA mortar with enhanced strength. However, a maximum strength of 23 MPa was achieved at 56 days with an optimal CBA replacement of 10%. This research demonstrates the potential by transforming industrial waste for low-carbon cement production to save the use of landfills for waste disposal and optimize consumption of non-renewable resources.
Determining datum temperature and apparent activation energy: an approach for mineral admixtures incorporated cementitious systems
The maturity method is used to predict the strength of concrete by monitoring its temperature history. Accuracy of maturity method relies on the dependable determination of the datum temperature and the apparent activation energy. The current study introduces a new approach, complementing those in ASTM C1074-11, for determining the datum temperature and apparent activation energy. The experimental study involved using two different mineral additives to portland cement at 6%, 20%, and 35% replacement amounts. The mortars were then cured at temperatures of 5, 20, and 40 °C, and their strengths were determined. Subsequently, the datum temperatures and apparent activation energies for these mixtures were calculated using both the proposed approach and the alternatives from ASTM C1074-11. Strength estimations were conducted in conjunction with commonly used maturity functions. The results indicate that the proposed approach determines the datum temperature and apparent activation energy reliably for mineral admixture-incorporated mortars. Furthermore, the predicted strengths, derived from the datum temperature and apparent activation energy calculated through the proposed approach, show a closer alignment with the experimental results when applying the Nurse-Saul and Hansen-Pedersen equations, as opposed to the Rastrup and Weaver-Sadgrove models.
Copyright (c) 2024 by the Authors. This is an open access article distributed under the CC BY licence. http://creativecommons.org/licenses/by/4.0
Optimum design of reinforced concrete beam sections with JAYA algorithm
Section design is an important process for designing reinforced concrete structures because of the existence of factors such as bearing capacity and cost. After defining the initial cross sections for reinforced concrete elements, reinforcement amounts are calculated within the framework of certain rules and regulations. In the classical method, optimum cost and reliable structure can be designed by trial and error. Designing with the classical method is quite time-consuming. As in different fields, metaheuristic algorithms are employed to civil engineering applications to reach the optimum solution. In this study, unlike other examples from the literature, the optimum cost design of reinforced concrete beam cross-section was done, adding torsional moment to bending moment and effects of shearing force through the use of the JAYA algorithm. The optimum cost design of a reinforced concrete beam section under the effects of torsional moment, bending moment and shear force is performed. The design is done according to the rules specified in ACI 318 (Building code requirements for structural concrete), as it is well-known and used in many international projects. For the purpose of this study, cross-sections of 10 different reinforced concrete beam cross-sections were designed under 5 different loads for 2 different concrete classes through MATLAB software, with the aim of finding the optimum beam cross-section. A reinforced concrete beam is designed under different torsional loads and for different concrete classes and it is aimed to find the optimum beam cross-section. It shows the effect of torsional force on reinforced concrete beam cross section and reinforcement by using different torsional loads. It was observed that the algorithm used tends to approach the optimum result, increasing the area of concrete with lower unit cost or reducing the distance between stirrups. It was concluded that Jaya algorithm performs effectively with respect to optimizing reinforced concrete beams. The algorithm used can be applied to different reinforced concrete elements.
Calcium aluminate cement based high early strength engineered cementitious composites with recycled artificial flaws
Engineered Cementitious Composites (ECC) is an ideal repair material due to its high durability and ductility. However, providing ECC with high early strength is challenging since strength and ductility, which are key to crack-free repair, are also interdependent. Thus, it is necessary to use artificial flaws in order to keep the ductility at reasonable levels while increasing the strength. This study uses calcium aluminate cement, a non-portland cement, as the primary binder to attain the early strength in the production of high early strength ECC for the first time. Besides, expanded glass and crumb rubber, both made by recycling waste materials, were included as artificial flaws to enhance ductility. The performance of designed high early strength ECC was assessed through mechanical, abrasion, shrinkage and non-destructive tests and compared with high early strength portland cement based ECC. It is revealed that a minimum compressive strength of 28.9 MPa and flexural strength of 7.1 MPa could be attained even at the age of as early as 6 hours after casting. Nevertheless, deformation capacities were significantly improved after 24 hours following the casting by the use of both artificial flaws. In addition, acceptable drying shrinkage and abrasion resistance values were obtained.
Determination of waste crushed baked clay aggregate concrete with granular composite material preparations
Waste baked clay is an industrial waste that causes environmental pollution. Therefore, the possible utilization of this material would reduce environmental pollution. Utilization of baked clay as aggregate in concrete would have a positive effect on the economy. There are many studies on examining concrete as a granular composite. However, there are few studies on the examination of industrial or construction demolition wastes, which are used as aggregate in concrete, with granular composite models. This study was conducted to contribute to filling this gap in the literature. In concrete production, Portland cement, river sand, 4-32 mm in size crushed stone and crushed baked clay as coarse and medium aggregate in the replacement ratio of 0%, 50% and 100% were used. Compression tests were conducted on specimens. Stress-strain curves were drawn as a graph. Elasticity modulus were determined experimentally. Elasticity modulus were calculated using granular composite models. Experimental and calculated elasticity modulus were compared and examined. According to the results, it was determined that these wastes could be evaluated in concrete production and used in the elasticity modulus calculation of granular composite models.
Copyright (c) 2024 Tulpar Academic Publishing http://creativecommons.org/licenses/by/4.0
Enhancing mechanical properties of foam concrete with sisal fiber reinforcement: An experimental investigation
In this study, we explore the possibility of using sisal fibers as an environmentally-friendly reinforcing agent for foam concrete. We aim to improve its physical properties by combining environmental friendliness with engineering practicality to create a durable material that can be used safely today and a supplier of ecological sustainability for tomorrow. Known for being lightweight and thermally insulating, foam concrete has very low tensile strength and ductility as compared with other materials. This is why its application is often limited in scope. We naturally think that adding sisal fibers, which are a high-performance and renewable resource in themselves, will improve these properties. It is well known that they have a tensile strength of more than 400 kg/cm, and their long, stiff lamellae further increase this advantage. As a result, we integrated sisal fibers at different mixing rates: 0 (no Sisal), 0.25g, 0.5g and so on up to 1% volume. After the test specimens were standardized like this they went into the hence examining each of these properties in turn. With a reasonable content of fibres, the mechanical properties of foam concrete improved significantly. It was observed that the properties of fresh concrete decreased slightly in the samples where 0.50% sisal fiber was used. However, the compressive strength increased by 12.9% compared to the reference sample, and the flexural strength increased by 2.85 times compared to the reference sample. This study not only confirms the feasibility of using sisal fibers to reinforce foam concrete theoretically, but it will also serve as a useful reference for the development of more sustainable scientific building materials. The author provides a discussion of their results and future directions for research on construction materials, highlighting environmental and economic benefits from incorporating natural fibers into these materials.
Copyright (c) 2024 by the Author. This is an open access article distributed under the CC BY licence. http://creativecommons.org/licenses/by/4.0
Investigation of structural performances of historical building elements made with local materials using the finite element method
The structural performance of the materials used in historical buildings can be damaged, usually due to natural events or human-induced interference. Historical buildings in the Southeastern Anatolia Region were generally built with local materials such as stone and brick. This situation should be seen as a factor that may cause severe structural damage in buildings located on a regionally active fault line. Within the scope of the study, the materials used in the region were discussed, and a numerical model representing the behavior of the materials against an earthquake that could occur on the fault line was used. Stone, brick and concrete material definitions were made for the prototype of the arch form modeled with SAP2000, and time-history analyses were carried out separately for each material. Concrete material behaviors, frequently used in buildings constructed today, are also included in the analysis for comparison. As a result of the study, it has been observed that local materials do not have sufficient tensile strength against earthquakes compared to concrete material and that the structures may face the risk of collapse in case of seismic movements in the region.
Investigation of the seismic response of irrigation channel using Coupled Eularian-Lagrangian approach
While devastating earthquakes affect cities, they can also cause serious damage to irrigation structures in agricultural areas. Cracks and structural deteriorations may occur in water structures using concrete such as dams, aqueducts and open channels. This study investigates the earthquake response of irrigation canals through fluid-structure interaction analysis. The earthquake response of an irrigation canal was examined by establishing fluid-structure interaction. Finite element models, with material properties and dimensions determined, were created and analysed with destructive earthquake records. In the finite element model, the behaviour of water inside the channel is simulated using the Coupled Eulerian-Lagrangian (CEL) approach. In the analyses, displacement and stress values were examined in the model without water, and in addition to these, fluctuations on the water surface were examined in the model with water. The observed changes are shown with graphs and contour diagrams. As a result, it was shown that hydrodynamic effects reduced horizontal displacements by 42% but increased the maximum principal tensile stresses by 49% and the maximum principal compressive stresses by 75%, compared to the non-water model. In addition, it was observed that in both models, the dynamic analysis values at the time of the earthquake increased by approximately 7‒13 times the static values before the earthquake. These findings underscore the importance of dynamic analysis using fluid-structure interactive models for safeguarding irrigation structures against seismic hazards, thereby ensuring food security in vulnerable agricultural regions. Therefore, it is important to perform dynamic analysis with fluid-structure interactive models for irrigation structures exposed to destructive earthquake forces.
A different approach for green concrete production: Determination of the effect of e-waste and waste rubber powder on durability properties of concrete
This study was carried out to present a different approach to green concrete production by utilizing electronic waste (e-waste) and waste rubber powders in order to provide a solution to both the cost and carbon footprint problems arising from the rapid consumption of aggregate resources and cement. For this purpose, 0%, 5% and 10% of e-waste was utilized instead of aggregate and 0%, 2.5% and 5% of waste rubber powder was utilized instead of cement. In addition, mixtures in which both wastes were combined in concrete were also prepared and comparisons were conducted. Capillary water absorption, acid and sulfate attack tests were carried out on the concretes with different wastes at the end of 28 and 90 days. The capillary water absorption of concrete produced with 5% waste rubber powder at the end of 28 days (P5E0/28) was 80% less than the control concrete (C/28) (these values were 0.46, 2.36 respectively). It was determined that the utilization of waste rubber powder had a decreasing effect on the compressive strength losses of the concretes after acid attack compared to the control concrete, while e-waste had an increasing effect. It was determined that the compressive strength losses of the concretes in which waste rubber powder and e-waste were combined against sulfate attack were positively differentiated from both control concrete and concretes produced with single waste type. In parallel with the weight and compressive strength losses obtained after acid and sulfate attack, the results of the visual analyses of the concretes were similar. The use of 5% waste rubber powder in the concrete produced the greatest results. In addition, the ideal ratio between concretes in which e-waste and waste rubber powder used together was determined as 5% waste rubber powder and 5% e-waste. The results verified that e-waste and waste rubber powder can be considered for the production of green concrete.
Predicting compressive strength of AAC blocks through machine learning advancements
Determining the strength properties of Autoclaved Aerated Concrete (AAC) through conventional compression experiments is both time-consuming and costly. Using sophisticated Machine Learning (ML) algorithms to forecast concrete compressive strength can expedite time-consuming experimental procedures and reduce expenses. In this study, four ML models were proposed, including Random Forest (RF), Support Vector Regression (SVR), Linear Regression (LR), and Stochastic Gradient Descent (SGD). These models were developed to forecast the compressive strength of AAC blocks based on a dataset of 525 cubic samples. By comparing the results using different evaluation indices, the study analyzed each input variable’s relative importance and impact on the output. The findings revealed that the SVR model had the least error and is thus the most suitable for concrete compressive strength estimation. This approach results in cost savings on both specimens and laboratory tests. Out of the seven input factors, which encompass the proportions of water, cement, sand, lime, fly ash, aluminum powder, and gypsum, the proportions of cement and water content were pinpointed as the most crucial characteristics. In contrast, aluminum powder and gypsum displayed less prominent significance.
Effect of resin amount on the damping properties of polymer concrete
In the construction and infrastructure sector, efforts are being made to find faster and more efficient materials. Polymer concrete (PC) challenges traditional concrete with its fast setting, durability and abrasion resistance. While studies on PC strength are abundant in the literature, studies on the effects of resin amount on damping capacity are fewer than mechanical performance. In this paper, the effect of resin proportion on damping capacity is investigated by modal tests. PC mixtures in the production with different resin proportions (11‒19%) were poured into molds of 10x25x500 mm, using aggregates of up to 3.15 mm in size. After 14 days, the natural frequency and damping ratios of the specimens up to 1000 Hz were determined in modal tests. While the damping ratio (DR) decreased in resin contents up to 17%, the results of the specimens with 19% resin ratio increased. However, when the products with the same resin ratio are analyzed, the random distribution of the aggregate affects the damping capacity. The main reason of negative correlation between resin amount and DR is the filler amount in the mixture. Because of the production consistency, fluidization of all the mixtures is prevented by adding fillers. Therefore, the impact of the resin amount on DR is limited or even negative. Besides that, to compare measurement results finite element method (FEM) analyzes are conducted. It can be said that the natural frequencies are not suited well especially in high frequency ranges due to frequency dependent properties (visco-elastic) of PC.
The impact of openings on ferrocement I-beams: a study on metallic and non-metallic mesh reinforcement
The primary objective of this investigation is to assess the influence of openings on the structural performance of ferrocement I-beams, incorporating diverse metallic and non-metallic mesh reinforcements. Sixteen beams underwent testing utilizing a four-point loading system until failure, categorized into four groups based on the type of mesh reinforcement. Each group comprised a control I-beam without openings and three additional beams featuring one, two, and three openings, respectively. To ensure consistent reinforcement weight, the four groups were reinforced with three layers of welded steel meshes, two layers of expanded metal meshes, two layers of Tensar meshes, and eight layers of Gavazzi meshes. Comparative analysis of the experimental outcomes was conducted with finite element models utilizing Abaqus. Therefore, there was good agreement between the experimental and numerical results. The findings showed that beams with no openings, one, and two openings reinforced with Gavazzi meshes had the highest ultimate load compared to other tested beams, while beams with three openings, those reinforced with expanded metal meshes had the greatest ultimate loads. Placing three openings in beams, with dimensions of 100×50 mm (two of these openings are approximately 10 cm apart from each edge while the third opening is located at mid-span), reduced the load-to-weight ratio by about 20.7%, 12.9%, 8.2%, and 23.8% for welded beams, expanded beams, Tensar beams, and Gavazzi beams, respectively, compared to the beams with no openings.
Advantageous approach for boron ores used in cement production: optimization of dehydration
Boron with a certain water content is used for industrial purposes, including cement production. It is necessary to perform and optimize heat treatments and determine the water content. The heat treatment is applied to boron ores that must be used for cement production. However, these processes take time and increase costs. With this study, it will be possible to obtain boron products with the desired properties in a shorter time by determining the optimal parameters for dewatering processes. Colemanite and ulexite ores were reduced to a grain size of 44 microns by ore dressing processes and subjected to dewatering. The Taguchi method was used to optimize the dehydration of colemanite and ulexite ores. The orthogonal design of experiments method L18(6132) 3 factors, 18 trials was chosen to determine the design of experiments. The changes in the H2O-CaO-Na2O-B2O3 concentrations were determined on the basis of the analyses performed. TG/DTA analyses were carried out for comparison with the dehydration processes. In the optimization processes performed using the Taguchi method, the maximum water removal was achieved with 1 g of ore and a period of 6 hours. H2O removal was 98.42% at 650 °C for colemanite and 99.1% at 300 °C for ulexite. It has been shown that the dehydration of ulexite and colemanite ores can be optimized and the boron product with the desired properties can be obtained in a short time, which is an advantage for its use in the cement industry. It is expected that this study will serve as an important basis for future applications of B2O3 cement.
The effect of the gravity on the earthquake performance of roller compacted concrete dams
Roller compacted concrete (RCC) is a dry concrete mixture often utilized in the construction of large dams. The interlayer of the RCC dam, which is the weakest plane of the structure, can easily fail under hydraulic shear load, geological impact, earthquake force and environmental impact. In this study linear and performance analyzes were carried out for eight different scenarios for foundation effect, gravity effect and empty and full reservoir situations. In analyses, the earthquake response and performance of the Akçakoca RCC Dam, taking into account the interaction between the dam and the water. The reservoir water behavior is simulated using the Eulerian-Lagrangian coupled (CEL) approach with finite elements modeling. Linear analyses reveal that hydrodynamic pressure leads to increased displacements and principal stresses. The earthquake performance evaluation of the Akçakoca RCC dam indicates that critical concrete damages are expected based on linear time-history analyses conducted for both empty and full reservoir scenarios. Besides, according to this study, gravity effect clearly increases the earthquake performance of the dam.
Reinforcement of concrete beams using waste carbon-nanoclay-fiberglass laminate pieces
In the last few decades, strengthening of structures in need of repair with fiber reinforced polymer (FRP) composite materials produced with different fiber types has gained great importance. Within the scope of this experimental study, the usability of hybrid glass and carbon composite laminates produced for different purposes and later cut into waste was investigated for concrete reinforcement. Hybrid composite laminates were produced in the form of glass-carbon-glass and carbon-glass-carbon, and the effect was investigated in two different sequences in the study. In addition, there are 3 different rates of nanoclay (0.50%, 0.75% and 1.25%) in the production of composite materials, and the effect of nanoclay ratio was investigated. In the study, two different numbers of composite laminates were adhered to the concrete samples produced in 70x70x280 mm dimensions and subjected to flexural strength test. In the Carbon-Glass-Carbon series using triple waste laminate pieces, the highest flexural strength was reported in the CGC-0.75-3 series, which achieved an increase of approximately 55% and 42% compared to the Control and Control-E series. It was determined that the effectiveness of the reinforcement technique of concrete with laminates in flexure did not change significantly depending on the number of laminate pieces. The main mode of failure in the experimental work was due to concrete fracture.
An overview on the hazards and handling methods of construction and demolition wastes: Special focus on recycled concrete aggregates
With the demand increased in construction activities within the last century, several scientific research studies have been focusing on different aspects of construction and demolishing wastes, while considering the severity of environmental problems that they cause. This work presents the results of out an extensive literature survey in order to provide an overview on the hazards and handling methods of construction and demolishing wastes. Results of this literature review indicate that landfilling has been the most commonly used method, even though the recycling of the construction and demolishing wastes was found out to be the most environmentally-friendly solution. It was observed that groundwater and soil may be heavily affected by the leaching constituents of landfilled construction wastes. On the other hand, using these wastes in the form of recycled concrete aggregates was observed to eliminate these hazards. The results of literature survey pointed out that the use of demolished concrete wastes as recycled concrete aggregates could be widely adopted by construction sector only if the resulting concrete is of satisfactory quality. Hence, information on different quality aspects of concrete made of recycled concrete aggregates are presented systematically as a clear guide in this work, to verify its feasibility as an environment-friendly waste elimination method.
Copyright (c) 2023 by the Authors. This is an open access article distributed under the CC BY licence. http://creativecommons.org/licenses/by/4.0
Effect of hemp and basalt fiber on fracture energy of cement-based composites: a comparative study
Fiber-reinforced composites are one of the most used construction materials. Nowadays, some types of fibers like steel, carbon, glass and basalt are commonly used in these composites. However, the production of these fibers consumes natural resources and a high amount of energy. Researchers have started working on natural fibers to reduce commonly used fibers productions’ drawbacks for more sustainable composites. However, the effect of natural fibers on the properties of cement-based composites -especially fracture energy- still needs further research and comparing with the behavior of commonly used fibers. In this study the effect of hemp fiber on the mechanical properties and fracture energy of cement-based fiber-reinforced mortar mixtures was investigated. The results were compared with those of the basalt fiber-reinforced mixtures. The results showed that the flexural strength and fracture energy improved with the use of hemp and basalt fiber compared to the fiber-free mixture. The flexural strength increased up to 10.7% and 19.6% with the inclusion of hemp and basalt fibers, respectively. The mean peak load and fracture energy of hemp fiber-reinforced mortar was higher than those of the fiber-free mixture by 32.2% and 17.9%, respectively. The corresponding values for basalt fiber addition 60.8% and 146.4%.
Copyright (c) 2023 by the Author. This is an open access article distributed under the CC BY licence. http://creativecommons.org/licenses/by/4.0
Copyright (c) 2023 Tulpar Academic Publishing http://creativecommons.org/licenses/by/4.0
Optimization of reinforced concrete beam using hybrid algorithms with multi-objective function as CO2 emission and cost
In this study, algorithms with two objective functions are defined considering the TS500 (2000) (Reinforced concrete structures design and construction rules) and TBDY (2018) (Turkey Building Earthquake Regulation) standards for rectangular beam design. These objective functions were determined as CO2 emission and cost. Optimizations were performed in MATLAB program using the Hybrid Algorithm of Teaching-Learning Based Optimization and Jaya Algorithm. In the case of using two objective functions, cases were created by multiplying the coefficient values found in the objective function according to the formula with the cost and CO2 emission values at different rates in order to prevent CO2 emission which is one of the biggest problems for the world. In the objective function, each rate used for CO2 and cost is implemented in a manner that increases or diminishes the impact of these values. In this way, comparisons were made between the cross-section dimensions to be formed according to not only impact rates but also the reinforcement area to be used, the CO2 emission and cost values that will arise as a result of these. Impact rates are related to cost and CO2 rate in the objective function, and the total rate is chosen as 1. Impact rates for cost are chosen as 0.1, 0.3 along with 0.5, and comparisons between the results are checked. In addition, recyclable and non-recyclable steel with different properties were used in separate analyses and the values were compared. Since the CO2 rate released by the non-recyclable steel is very high compared to the recyclable steel, the results show that the CO2 emission value is higher and this causes the objective function value to increase.
Mechanical, durability and solar reflectance properties of colored self‒compacting concrete
Urbanized areas are known to have significantly higher temperatures than rural areas. The Urban Heat Island (UHI) effect is caused by surfaces such as asphalt, buildings, and other heat-absorbing surfaces that store more heat than natural vegetation. Sunlight reflecting properties of building materials are improved with different applications. The present study investigates the mechanical, durability and solar reflectance properties of the colored self-compacting concrete. SCCs containing yellow, green, and black pigments were produced and evaluated. The fresh properties were determined with the slump, L-Box and V-funnel tests. Furthermore, compressive strength, solar reflectance and magnesium sulfate resistance tests were conducted. Yellow pigment added SCC showed a great potential (with the albedo of 0.42) in terms of solar reflectance and decreasing the contribution to the urban heat island effect.
Performance of light weight ferrocement composite walls
The aim of this research is to examine the performance of reinforced lightweight ferrocement walls under vertical and horizontal loading. The walls were made up of two thin layers of ferrocement reinforced with one, two, three, or four layers of welded wire mesh or expanded steel mesh. The panels’ core was constructed of lightweight extruded foam. An experimental program of thirteen lightweight walls with total dimensions of 100x650x1250 mm was casted to achieve this goal and tested until failure. ABAQUS finite-element package was conducted. The parameters in this study were the kind of reinforcement; welded and expanded wire meshes, the steel bars, and. the number of layers of steel mesh. Ultimate load, mode of failure, initial cracking load, service load, energy absorption, and ductility ratio were calculated and observation to evaluate the findings. The findings displayed that the performance of the ferrocement walls reinforced with expanded wire meshes is better than that of the walls reinforced with welded wire meshes. The energy absorbed increased by 40 % for specimens reinforced with expanded wire meshes is more than that of the walls reinforced with welded wire a good agreement was observed among the theoretical and experimental observations. This paper highlights uses of employing light weight ferrocement units in building of economic housing, which is particularly valuable for both developed and developing nations, with significant frugal benefits.
Evaluation of the lightweight foamed concrete characteristics
The purpose of this paper is to assess the properties of light weight foamed concrete. In this research, two phases are investigated. The first stage explored the characteristics of fresh and hardened foamed concrete using a foaming agent. The following parameters were employed in this study: foaming agent used as a volume of concrete mix by 10, 20, and 40%, fly ash used as a replacement of cement content by 10, 25, and 50%, and polypropylene fiber used with varied volume fractions of 0.5, 0.75, and 1.0%. Slump values are applied to evaluate the fresh properties. To evaluate the hardened concrete, the dry density and compressive strength at 7 and 28 days are computed. Furthermore, the 28-day tensile splitting strength and flexural strength are studied. The effect of a high temperature was evaluated. The second stage investigated the effects of polypropylene fiber on both fresh and hardened concrete. It was observed that foaming agents improve fresh characteristics while decreasing compressive strengths and dry density. Furthermore, utilizing fly ash improves the characteristics of both fresh and hardened foamed concrete. The fiber reduces the fresh characteristics while enhancing the toughened properties. Because of its low density, foamed concrete is being used for structural applications because of this study. Such as those utilized for thermal insulation, acoustic impedance, and fire breaks. Also used to create road foundations for roads built on soft soil.