Practicability and environmental impact assessment of synthetic fibre reinforced polymer (SFRP) stirrups in reinforced concrete beams.

In this study, the objective is to explore the practicability of incorporating synthetic fibre reinforced polymer (SFRP) stirrups into reinforced concrete beams. This investigation revolves around evaluating their effectiveness from two key perspectives: their structural performance and environmental impact. To accomplish this, four set of specimens were prepared, each integrating SFRP stirrups, and testing them under a rigorous three-point bending load test. The structural performance analysis entails a comprehensive examination on the critical design factors such as: the load-deflection relationship and the contribution these SFRP stirrups to improve the ductility performance, flexural stiffness, deformability factor, flexural toughness and energy absorption capacity. The findings of this study indicate that the SFRP stirrups exhibit commendable shear capacity, meeting the necessary requirements, and simultaneously demonstrate satisfactory ductility. It is determined, that the optimal design for these SFRP stirrups involves utilizing narrow and thin stirrups placed at relatively larger intervals. Furthermore, this research delves into assessing the environmental impact of incorporating SFRP stirrups. This assessment enables us to comprehensively evaluate the environmental implications of the entire life cycle of these stirrups in structural beam. Moreover, the analysis reveals that, SFRP stirrups yields lower environmental impacts compared to their steel counterparts, they still provide valuable insights into the overall sustainability considerations within the context of reinforced concrete structures.

Characterization of MSW incineration bottom ash for use as structural fill in reinforced soil structures: Geoenvironmental, geotechnical and economical assessment.

The study presents the geoenvironmental and geotechnical characterization of MSW incineration bottom ash (IBA) and examines its reuse as structural fill in reinforced soil structures (RSS).The suitability of reuse has been assessed with regard to international regulatory standards. The prime focus of the work remains on evaluating the pullout response of geosynthetic reinforcements through IBA fill to determine the interaction coefficient, which has never been addressed in the literature. The economic viability of using IBA instead of locally available river sand for a 12 m high MSE wall is also established. The column leaching test results confirm that IBA can be utilized in RSS with suitable design measures. The geotechnical investigation shows that IBA is a well-graded, non-plastic lightweight material with adequate drainage and high shear strength. The pullout test results demonstrate that the interaction coefficient of polymeric strips and geogrid in IBA (0.73-1.53 and 0.79-1.91, respectively) is comparable or higher to materials conventionally used as structural fill in RSS, indicating adequate bondage between IBA and geosynthetic reinforcement. Further, it is estimated that using IBA as a substitute for available river sand in the vicinity can potentially reduce the overall RSS project cost by 15-20%, even if IBA has to be transported 50 km away from the project site.

Assessment of Waste Marble Powder on the Mechanical Properties of High-Strength Concrete and Evaluation of Its Shear Strength.

Currently, the costs of building materials, especially cement, are increasing. Waste marble powder (WMP) could be used as a cement replacement material to produce environmentally friendly concrete to help preserve resources and reduce environmental pollution. The study's goals are (1) to evaluate the effects of using marble powder in place of cement in high-strength concrete (HSC) on the material's mechanical properties and durability characteristics. (2) The study is expanded to assess the effect of using partial WMP on the shear behavior of HSC beams under static loads. Eight half-scale simply supported reinforced beams with and without WMP have been tested. Each beam's cross-section was 120 × 200 mm, and each beam had a total length of 1000 mm. The ratios of the used WMP were 0%, 2.5%, 5%, 7.5% by weight, and two different stirrup ratios, 0% and 0.47%, were used. When applied to HSC beams with and without WMP, the shear strength provisions of two of the most used codes, such as the locally used Egyptian Code (ECP 207) and the internationally used American Concrete Institute's (ACI-2019), were examined. Using the ABAQUS software, the experimental results were compared to the findings of the nonlinear finite element analysis. The results established that partial replacement of cement by WMP led to increases in the concrete's compressive and tensile strengths of about 15% and 16%, respectively. When tested specimens were exposed to acid attack, there were slight losses in weight and compressive strength (1.25% to 2.47%) for both with and without the addition of WMP. Both the concrete with and without WMP showed the same level of water absorption. Additionally, WMP led to an enhancement in the shear capacities for all beams. Increasing the WMP ratio from 0% to 2.5%, 5%, and 7.5% increased the shear capacity by about 13%, 20%, and 28%, respectively, for beams without stirrups, while for beams with stirrups, the shear capacity improved by 12%, 19%, and 25%, respectively. The enhancement in the beams' shear capacities could be attributed to the advanced concrete matrix produced by WMP's extremely small particle size.

Assessment of Surface Treatment Degree of Steel Sheets in the Bonding Process.

The aim of the paper is to determine the influence of the surface treatment on the adhesive properties of steel sheet surfaces and the strength of the adhesive joints of steel sheets. The paper also aims to assess the degree of steel sheets' surface treatment in the bonding process. Due to the many methods of surface treatment and types of materials, the assessment of the surface treatment method is extremely important in adhesive processes. Two variants of the surface treatment were used: without a paint coating and with a paint coating, divided into two groups (without degreasing and with degreasing). Additionally, in the case of the analysis of the steel samples without the paint coating, mechanical treatment was applied. Two-component epoxy adhesive, prepared on the basis of bisphenol A and a polyamide curing agent, was used to prepare the single-lap adhesive joints of the steel sheets. The tests determined: (i) the adhesive properties of the steel sheets' surface based on the measurement of the contact angle of polar and apolar liquids (including wettability, work of adhesion, and surface free energy), (ii) surface roughness parameters (PN EN ISO 4287), and (iii) mechanical properties (load capacity and shear strength) of the steel sheets' adhesive joints (EN DIN 1465). Contact angle measurements of the steel sheet surfaces showed that the polar liquid better reflects the obtained strength results of the analyzed adhesive joints than the apolar liquid. Furthermore, better wettability of the surface of steel sheets with both polar and apolar liquids was obtained for samples whose surface was subjected to degreasing. It can also be concluded that the wettability of the surface can be used as one of the indicators of the degree of the surface treatment for the bonding process.

Urease production using corn steep liquor as a low-cost nutrient source by Sporosarcina pasteurii: biocementation and process optimization via artificial intelligence approaches.

To commercialize the biocementation through microbial induced carbonate precipitation (MICP), the current study aimed at replacing the costly standard nutrient medium with corn steep liquor (CSL), an inexpensive bio-industrial by-product, on the production of urease enzyme by Sporosarcina pasteurii (PTC 1845). Multiple linear regression (MLR) in linear and quadratic forms, adaptive neuro-fuzzy inference system (ANFIS), and genetic programming (GP) were used for modeling of process based on the experimental data for improving the urease activity (UA). In these models, CSL concentration, urea concentration, nickel supplementation, and incubation time as independent variables and UA as target function were considered. The results of modeling showed that the GP model had the best performance to predict the extent of urease, compared to other ones. The GP model had higher R2 as well as lower RSME in comparison with the models derived from ANFIS and MLR. Under the optimum conditions optimized by GP method, the maximum UA value of 3.6 Mm min-1 was also obtained for 5%v/v CSL concentration, 4.5 g L-1 urea concentration, 0 µM nickel supplementation, and 60 h incubation time. A good agreement between the outputs of GP model for the optimal UA and experimental result was obtained. Finally, a series of laboratory experiments were undertaken to evaluate the influence of biological cementation on the strengthening behavior of treated soil. The maximum shear stress improvement between bio-treated and untreated samples was 292% under normal stress of 55.5 kN as a result of an increase in interparticle cohesion parameters.

Assessment of the Undrained Shear Strength and Settlement of Organic Soils under Embankment Loading Using Artificial Neural Networks.

In engineering practice, due to the high compressibility and very low shear strength of organic soils, it is difficult to construct an embankment on organic subsoil. High variability and significant change in geotechnical parameters cause difficulties in predicting the behavior of organic soils under embankment loading. The aim of the paper was to develop empirical relationships used in the preliminary design for evaluating the settlement and undrained shear strength of organic subsoil loaded by embankment based on data obtained from four test sites. Statistical multiple regression models were developed for evaluating the settlement in time and undrained shear strength in time individually for peat and gyttja. Neural networks to predict the settlement and undrained shear strength in time for peat and gyttja simultaneously as double-layer subsoils as well as a separate neural network for peat and a separate neural network for gyttja as single-layer subsoils were also developed. The vertical stress, thickness, water content, initial undrained shear strength of peat and gyttja, and time were used as the independent variables. Artificial neural networks are characterized by greater prediction accuracy than statistical multiple regression models. Multiple regression models predict dependent variables with maximum relative errors of about 35% to about 60%, and neural networks predict output variables with maximum relative errors of about 25% to about 30%.

A Survey on Applications of Artificial Intelligence for Pre-Parametric Project Cost and Soil Shear-Strength Estimation in Construction and Geotechnical Engineering.

Ensuring soil strength, as well as preliminary construction cost and duration prediction, is a very crucial and preliminary aspect of any construction project. Similarly, building strong structures is very important in geotechnical engineering to ensure the bearing capability of structures against external forces. Hence, in this first-of-its-kind state-of-the-art review, the capability of various artificial intelligence (AI)-based models toward accurate prediction and estimation of preliminary construction cost, duration, and shear strength is explored. Initially, background regarding the revolutionary AI technology along with its different models suited for geotechnical and construction engineering is presented. Various existing works in the literature on the usage of AI-based models for the abovementioned applications of construction and maintenance are presented along with their advantages, limitations, and future work. Through analysis, various crucial input parameters with great impact on the estimation of preliminary construction cost, duration, and soil shear strength are enumerated and presented. Lastly, various challenges in using AI-based models for accurate predictions in these applications, as well as factors contributing to the cost-overrun issues, are presented. This study can, thus, greatly assist civil engineers in efficiently using the capabilities of AI for solving complex and risk-sensitive tasks, and it can also be used in Internet of things (IoT) environments for automated applications such as smart structural health-monitoring systems.

Introducing Fractal Dimension for Interlaminar Shear and Tensile Strength Assessment of Mechanically Interlocked Polymer-Metal Interfaces.

The interlaminar strength of mechanically interlocked polymer-metal interfaces is strongly dependent on the surface structure of the metal component. Therefore, this contribution assesses the suitability of the fractal dimension for quantification of the surface structure, as well as interlaminar strength prediction of aluminum/polyamide 6 polymer-metal hybrids. Seven different surface structures, manufactured by mechanical blasting, combined mechanical blasting and etching, thermal spraying, and laser ablation, are investigated. The experiments are carried out on a butt-bonded hollow cylinder testing method that allows shear and tensile strength determination with one specific specimen geometry. The fractal dimension of the metal surfaces is derived from cross-sectional images. For comparison, the surface roughness slope is determined and related to the interlaminar strength. Finally, a fracture analysis is conducted. For the investigated material combination, the experimental results indicate that the fractal dimension is an appropriate measure for predicting the interlaminar strength.

Assessment of the Shear Strength of Pile-to-Soil Interfaces Based on Pile Surface Topography Using Laser Scanning.

This article presents in situ research on the side surface of continuous flight auger (CFA) foundation piles using a three-dimensional (3D) laser scanner (Leica ScanStation C10) in order to evaluate the morphology assessment of pile concrete surfaces in various geotechnical layers. Terrestrial laser scanning describes the 3D geometry of the construction with high spatial resolution and accuracy. A total of six areas were selected from the acquired point cloud for which a two-step approach for removing the form was applied. In the first step, the reference surface was fitted using the least squares method, and then, cylindrical projection of the surface was performed. In the second step, an operator of removal of the multi-plane form was applied. For each sample, height parameters (Sq, Ssk, Sku, Sp, Sv, Sz, Sa) and functional volume parameters (Vmp, Vmc, Vvc, Vvv) according to the standard ISO 25178-2:2012 were determined. Significant differences in the values of surface height and functional volume parameters were observed for each geotechnical layer where piles were formed. Because the piles remain embedded in the ground, in situ tests of the side surface of piles are rarely performed and taken into account in the assessment of pile bearing capacity. The study of surface topography is a crucial stage in the assessment of the shear strength at the interface between a concrete pile and the soil layer. The obtained concrete morphology assessments are applicable during the determination of the skin friction factor in the analytical or numerical estimation of pile shaft resistance. The proposed procedure of morphology evaluation may improve the fidelity of the assumed friction factor between the concrete and soil and increase the reliability of direct shear experiments.

Functional assessment of the ex vivo vocal folds through biomechanical testing: A review.

The human vocal folds are complex structures made up of distinct layers that vary in cellular and extracellular composition. The mechanical properties of vocal fold tissue are fundamental to the study of both the acoustics and biomechanics of voice production. To date, quantitative methods have been applied to characterize the vocal fold tissue in both normal and pathologic conditions. This review describes, summarizes, and discusses the most commonly employed methods for vocal fold biomechanical testing. Force-elongation, torsional parallel plate rheometry, simple-shear parallel plate rheometry, linear skin rheometry, and indentation are the most frequently employed biomechanical tests for vocal fold tissues and each provide material properties data that can be used to compare native tissue to diseased or treated tissue. Force-elongation testing is clinically useful, as it allows for functional unit testing, while rheometry provides physiologically relevant shear data, and nanoindentation permits micrometer scale testing across different areas of the vocal fold as well as whole organ testing. Thoughtful selection of the testing technique during experimental design to evaluate a hypothesis is critical to optimize biomechanical testing of vocal fold tissues.

Evaluation of the relationship between the cost and properties of glass ionomer cements indicated for atraumatic restorative treatment

The aim of this study was to evaluate microshear bond strength (μSBS), water sorption and solubility of glass ionomer cements (GIC) indicated for atraumatic restorative treatment (ART). Cylindrical specimens (6x2.4 mm) were used to test the sorption and solubility of each GIC (n = 5). The specimens were weighed before and after immersion in water and desiccation. For the μSBS test, 60 primary molars were ground to obtain flat surfaces from both enamel and dentin. The teeth were then assigned to the tested GIC (n = 10) groups, namely Fuji IX - FIX, Ketac Molar - KM and Maxxion R – MX. The exposed surfaces were pre-treated with GIC liquid. Polyethylene tubes were placed on the pre-treated surface and filled with one of the GIC. After 24 h, the specimens were submitted to the μSBS test. The failure mode was assessed using a stereomicroscope (400x magnification). The powder to liquid ratio and cost of material were also determined (n = 3). The data were analyzed by ANOVA and Tukey's post hoc test. Linear regression was used to determine the relation between cost and the other variables. Overall, MX showed lower μSBS values (enamel: 3.93 ± 0.38; dentin: 5.04 ± 0.70) than FIX (enamel: 5.95 ± 0.85; dentin: 7.01 ± 1.06) and KM (enamel: 5.91 ± 0.78; dentin: 6.88 ± 1.35), as well as higher sorption and solubility. The regression analyses showed a significant and positive correlation between cost and μSBS in enamel (R2 = 0.62; p < 0.001) and dentin (R2 = 0.43; p < 0.001); and a negative correlation between cost and water sorption (R2 = 0.93; p < 0.001) and solubility (R2 = 0.79; p < 0.001). In conclusion, the materials indicated for ART exhibit distinct physical and mechanical properties; in addition, low-priced materials may interfere with GIC properties.

Assessment of Bond Strength between Metal Brackets and Non-Glazed Ceramic in Different Surface Treatment Methods.

OBJECTIVE: The aim of this study was to evaluate the bond strength between metal brackets and non-glazed ceramic with three different surface treatment methods. MATERIALS AND METHODS: Forty-two non-glazed ceramic disks were assigned into three groups. Group I and II specimens were etched with 9.5% hydrofluoric acid. Subsequently in group I, silane and adhesive were applied and in group II, bonding agent was used only. In group III, specimens were treated with 35% phosphoric acid and then silane and adhesive were applied. Brackets were bonded with light-cured composites. The specimens were stored in water in room temperature for 24 hours and then thermocycled 500 times between 5°C and 55°C. RESULTS: The difference of tensile bond strength between groups I and III was not significant (P=0.999). However, the tensile bond strength of group II was significantly lower than groups I, and III (P<0.001). The adhesive remnant index scores between the three groups had statistically significant differences (P<0.001). CONCLUSION: With the application of scotch bond multi-purpose plus adhesive, we can use phosphoric acid instead of hydrofluoric acid for bonding brackets to non-glazed ceramic restorations.

Avaliação da variabilidade em experimentos na área de dentística aplicada a testes de resistência ao cisalhamento / Assessment of variability in experiments in the operative dentistry area applied to shear bond strength tests

Objetivo: Avaliar a distribuição do coeficiente de variação (CV) em experimentos na área de Dentística envolvendo testes de resistência ao cisalhamento utilizando dentes humanos, publicados em vários periódicos, assim como na base de dados Medline-Pubmed. Material e método:Foi realizado um levantamento bibliográfico em que se determinou o valor médio de CV da variável estudada, tanto em periódicos nacionais e internacionais publicados entre 1998 e 2004, como também naqueles presentes na base de dados Medline-Pubmed (1991 a 2005). Resultado: Os dados encontrados foram tabulados e sua normalidade foi testada utilizando o programa SAS - Statistical Analysis System (Shapiro-Wilk, a = 0,05). Posteriormente, foram propostos os limites das faixasde classificação, utilizando-se a relação entre média e desvio padrão dos valores de CV. A média do CV de estudos envolvendo testes de resistência ao cisalhamento foi igual a 25,88. Conclusão: A análise dos dados permitiu definir que, para a variável estudada, os valores de coeficiente de variação são considerados baixos quando o CV ≤ 18,46; médios quando 18,46 < CV * 25,88; altos quando 25,88 < CV * 34,00 e muito altos quando CV > 34,00.

The aim of this work was to assess the coefficient of variation (CV) distribution in experiments in the Dentistry area, involving shear strength tests using human teeth, published in various periodicals, as well as in the Medline-Pubmed data base. Material and method: A bibliographic survey was made in national and international periodicals published between 1998and 2004, as well as in those in the Medline-Pubmed (1991 to 2005) data base. Result: The data found (central tendency and dispersion measurements) were tabled and their normality was tested using the program SAS - Statistical Analysis System (Shapiro-Wilk, a = 0.05). As the data did not present normal distribution, limits of the classification ranges were proposed, and the quartiles were used. The CV median of the studies involving shear strength tests was equal to 25.88.Conclusion: Data analysis allowed one to define that for the studied variable, the coefficient of variation values are considered low when o CV ≤ 18,46; medium when 18.46 < CV * 25.88; high when 25.88 < CV * 34.00 and very high when CV > 34.00.