Subjects -> SCIENCES: COMPREHENSIVE WORKS (Total: 426 journals)
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 Arabian Journal for Science and EngineeringJournal Prestige (SJR): 0.303 Citation Impact (citeScore): 1Number of Followers: 5      Hybrid journal (It can contain Open Access articles) ISSN (Print) 2193-567X - ISSN (Online) 2191-4281 Published by Springer-Verlag  [2658 journals]
• Correction to: Experimental Examination of the Behavior of
Shotcrete-Reinforced Masonry Walls and Xgboost Neural Network Prediction
Model

Abstract: A Correction to this paper has been published: https://doi.org/10.1007/s13369-021-05466-1
PubDate: 2021-11-01

• Changes of Water/Ice Morphological, Thermodynamic, and Mechanical
Parameters During the Freezing Process

Abstract: To reduce ice adhesion hazards, optimize or develop the anti/de-icing methods, it is necessary to understand the change of freezing parameters during the freezing process, such as thermodynamic, morphological, and mechanical parameters. The present study investigates the freezing characteristics by purpose-built devices to describe the freezing process quantitatively. Morphological parameters were calculated the reverse engineering. The results showed that the inner temperature and morphology of water droplet were obviously changed, and the freezing process could be mainly divided into three stages: initial and spreading, freezing, and steady-state. Moreover, an experimental apparatus that measured the phase swelling force was built on investigating the freezing process of water from the mechanical aspect. It was found that the swelling force generated from the freezing process of 2473 mm3 water could reach 46.38 N. The generation process of swelling force could also be separated into three stages: non-expansive stage, increasing stage, and stable stage. The formation stage of swelling force was similar to that of ice. Combining the measured expansion force with the calculated freezing parameters based on the observed test, the freezing process of water could be better understood. The study would help researchers and engineers understand the freezing process and provide some freezing characteristics parameters for the anti/de-icing research.
PubDate: 2021-11-01

• Basement-Storey Effect on the Seismic Response of RC Buildings on Soft
Surface Soil

Abstract: The effects of the basement storey on the seismic behavior of RC buildings built on near-surface alluvial soft soil are studied in this study. Numerical building models with and without a basement and with different numbers of stories are developed. Time-history dynamic analysis of the structure–soil models was performed using the specialized geotechnical software package PLAXIS-2D. In the first phase of the finite element analysis, the settlement on the soil under the static loads of the building was determined. In the second phase, the earthquake responses of RC buildings with and without a basement storey in terms of lateral displacement were examined by considering the determined stresses after the static loading. The results of the numerical models demonstrate that when the height of the RC buildings is increased, the seismic response of RC buildings without basement storey is detrimentally affected.
PubDate: 2021-11-01

• Performance and Durability of Cellulose Pulp-Reinforced Extruded
Earth-based Composites

Abstract: This study aimed to investigate the influence of two alternative cellulosic materials: bamboo organosolv pulp and recycled waste carton pulp, on the flexural strength, fracture toughness, drying shrinkage, and durability of extruded earth-based building materials by varying the reinforcement content at 5, 7.5, and 10 wt%. The results show the flexural strength and fracture toughness achieved by the inclusion of carton pulp were between the range of 2.87–3.20 MPa and 4.22–4.52 MPa.m0.5, respectively, while the introduction of bamboo pulp gave 2.04–2.20 MPa and 3.76–4.05 MPa.m0.5, respectively. Compared with the unreinforced material, composite reinforced with 5 wt% of recycled waste carton pulp significantly enhanced flexural strength (61%), specific energy (416%), and fracture toughness (57%), while increasing the drying shrinkage (81%) and water absorption (38%) and decreasing the bulk density (15%) of earth-based matrix. Although the addition of cellulose pulp in soil matrix increased the drying shrinkage due to the high absorption capacity of pulp fibre, it decreased the wearing percentage and the shrinkage cracking of the composite which contributed to an improvement in the durability of the earth-based material. The repeated drying shrinkage test led to an improvement in the dimension stability at 87%, 83%, 85%, and 82% for 0, 5, 7.5, and 10 wt% of recycled pulp composite, respectively. Cellulose fibre reacts as crack arrester during loading and shrinkage, improves the durability, and provides a lightweight earth wall material for insulation strategies.
PubDate: 2021-11-01

• Determination of Dynamic Behavior of Masonry Structure Using with
Operational Modal Analysis Technique

Abstract: It is a very difficult engineering issue to assess the earthquake performance levels of existing masonry structures and determine whether they require strengthening or retrofitting. The materials used in the production of masonry structures vary from region to region, even within the same structure, and the lack of standard mechanical properties of these materials makes it difficult to define the material model in the numerical models of such structures. It is known that these problems are eliminated by the Operational Modal Analysis (OMA) technique because it does not damage the structure and accelerates the process. In the framework of this research, experimental measurement of the 5-story masonry structure was taken with OMA, and numerical modeling was made by SAP2000v14 software. The damping ratio, natural frequencies, and mode shapes of the structure were determined. Frequency-domain-based methods were used in the analysis and evaluation of OMA responses from the Enhanced Frequency Domain Decomposition Method (EFDDM), while the Stochastic Subspace Identification Method (SSIM) was used for time-domain-based methods.
PubDate: 2021-11-01

• Deformation Properties of Nano-Silica Modified Concrete Mixtures under

Abstract: The enhancement that nano-silica (NS) constitutes in the microstructure of concrete would affect its deformation behavior. In this work, the pre-peak and post-peak stress–strain diagram characteristics of concrete mixtures with NS (1.5% of cement by wt.) under uniaxial compression were investigated. The results were compared with the mixtures containing micro-silica (MS) (7.3% of cement by wt.). Aggregate characteristics in the range of 16 to 22 mm, as another variable, were also changed by utilizing river gravel (RG II) or crushed sandstone (CS II). Compared to reference concrete, the addition of NS did not improve the compressive strength and modulus of elasticity significantly. However, the addition of only 1.5% NS significantly affected the stress–strain diagram characteristics, such as discontinuity and critical stress limits before the peak load. Relative to the mixtures containing MS, the effect of NS on the pre-peak region was more significant. For example, when the mixtures containing RG II as coarse aggregate are considered, with respect to reference mixture, the increase in normalized discontinuity stress limits at 28 days was found as 52% and 26%, respectively, for the mixtures containing NS and MS. However, in the same order, the increase in 28-day compressive strength was just 8.1% and 5.2%. Post-peak behavior of the mixtures also indicated that the fracture of concrete is more brittle when MS or NS is used. Among these, the effect of NS on the post-peak region was found to be more dominant.
PubDate: 2021-11-01

• Deformation Behavior of Shield Segment Joint Controlled by Bolt and
Positioning Tenon

Abstract: The deformation failure of a shield segment joint can lead to serious leakage, and the joint must therefore be reinforced in advance to control its deformation. The combination of a bolt and positioning tenon, as a new type of reinforcement, can quickly control the deformation of shield segment joints. Numerical simulation is conducted to analyze the variation characteristics of bolt stress, bolt groove stress, and deformation of segment displacement under the vertical load of a preloading bolt. Results indicate that the most important factor in resisting the deformation of segment displacement under a vertical external force is bolt preloading. Greater bolt preloading leads to greater friction resistance between segments and stronger resistance against segment displacement deformation. The positioning tenon can effectively reduce the displacement between shield segments, and the average displacement can be reduced to approximately 60%. The control of the deformation mechanical behavior of shield segment joints by a bolt and tenon provides a theoretical reference for practical engineering.
PubDate: 2021-11-01

• An Analysis of Floating Geogrid-Reinforced Pile-Supported Embankments
Containing Deep Softened Soil

Abstract: Floating geogrid-reinforced piles provide economic solutions when constructing embankments over areas with soft soil. The combination of piles and geogrids allows for the transfer of stress between the piles and adjacent soil through soil arching and tensioned membrane effects. Furthermore, floating geogrid-reinforced pile foundations can also significantly reduce embankment settlement. However, it has been found that in many cases, the ends of the piles may not be anchored due to layers of thick softened soil. Therefore, reduced scale model tests and numerical simulations were conducted in the current study for the purpose of evaluating the performances of different types of end-bearing and floating piles. The effects of different parameters were considered, including embankment filling heights; pile spacing ratios; stiffness ratios between the piles and the adjacent subsoil; internal friction angles of the embankment fill; and the effects of the tensile stiffness of the geogrids on the bearing capacities of the embankments. The results showed that the absence of firmly supported layers could transfer loads and reduce settlement. The results of this study’s numerical simulations revealed that enlarging the pile-soil stiffness ratios or tensile stiffness, and improving the shear properties of embankment fill could successfully improve the performances of geogrid-reinforced pile-supported embankments. This study’s findings can potentially be used to guide future analyses of floating pile load transfer mechanisms and settlement patterns.
PubDate: 2021-11-01

• Transportation Performance of Large-Sized Pebbles in Slurry Circulation
System: A Laboratory Study

Abstract: The slurry circulation system is a key component of a slurry-pressure-balanced shield tunnel because it facilitates the effective operation of slurry shield tunnelling. However, the research on transportation performance including critical velocity and motion characteristics of large-sized pebbles is scant because it is difficult to observe the performance of pebbles. In this study, an indoor test was designed and built to observe the transportation performance of large-sized pebbles in a slurry circulation system. This test takes a lot of time because obtaining the critical velocity and observing the motion characteristics are extremely complex. Herein, we find a slurry substitute solution that conveniently allows observation of the transport characteristics of pebbles. In addition, to analyze the velocity of the transportation of large-sized pebbles more accurately, we redefined the critical velocity of pebble transportation in the slurry system and corrected the prediction formula of critical velocity proposed by Wasp. The results show that the critical velocity of pebbles at the turning joints is the highest in the whole slurry circulation system. The particle property parameter (FL) proposed by the Wasp formula was corrected to 0.536, 0.563 and 0.683 for pebbles with flat shape, ellipsoid shape and near-spherical shape, respectively. The motion of large-sized pebbles in the circulation pipeline mainly manifests in three forms: sliding, rolling and jumping. The motion characteristics of pebbles in the circulation pipeline and their impacts on the pipeline are analyzed. The results can provide guidance for designing and preparing the slurry circulation system of slurry shield tunnelling projects.
PubDate: 2021-11-01

• Linear Transient Dynamic Analysis of Plates With and Without Cutout

Abstract: The present work exhibits the analysis of a plate with and without cutout considering the dynamic analysis in a transient zone with its application in the civil, structural, and aerospace industry. For this, first-order shear deformable C0 continuous Finite Element (FE) is implemented to examine transient response of plate. The governing ODE of motion’s is integrated using central difference explicit time integration scheme. A lumped mass matrix is obtained by a special diagonlization scheme and the total mass of the element is conserved by inducing effective rotary inertia terms. A FE program is developed based on derived FE formulation to investigate the effect of dynamic loading on such plates. The analysis exhibits the results in terms of displacement, forces, and bending moment of the plate for various aspect ratios and different parameters. The results are shown in terms of tables and graphs for smaller to larger cutout in plates with its different aspect ratio considering transient analysis. The results reveal that transient dynamics analysis shows a considerable difference in the behavior of plates with and without cutout in terms of time period, amplitude, and bending moment than that obtained from static analysis.
PubDate: 2021-11-01

• Evaluation of Moisture Damage of Cold Patch Asphalt Using the Surface Free
Energy Method

Abstract: Cold patch asphalt is more preferable in pavement construction compared to hot mix asphalt from the perspective of environmental conservation. However, the cold patch asphalt mixture is prone to moisture damage for production at lower temperatures and the presence of a diluent. The objective of this paper is to evaluate the moisture induce damage potential of cold patch asphalt mixture based on surface free energy theory. Three kinds of cold patch asphalts were synthesized by base asphalt, abietic resin, diesel, and anti-stripping agent, while the aggregates consisted of limestone and basalt. The surface free energy components of cold patch asphalt and aggregates were measured using the high-precision automatic Tensiometer System and Gravimetric Sorption Analyzer, respectively. The analytical computation to assess cohesive bond energy, wettability, adhesion bond energy, and energy ratio was obtained after surface free energy calculations. The results showed that the mixture of additives decreased the surface free energy of cold patch asphalt. Moreover, diesel can increase the surface free energy of pure asphalt. However, the abietic resin and anti-stripping agent have an adverse effect. Therefore, it can be concluded that the cold patch asphalt synthesized in this study has better resistance to water damage ability than base asphalt. More cold patch asphalt and aggregates are strongly suggested to validate the findings of this research.
PubDate: 2021-11-01

• A Review of Studies on Asphalt Fine Aggregate Matrix

Abstract: Asphalt fine aggregate matrix (FAM) consists of a binder, fine aggregate, filler, and air voids. Studies on FAM, which is one scale smaller than asphalt concrete (AC), have been gaining attention among researchers because of its considerable similarities with AC and increased testing efficiency it provides. FAM tests are mostly performed to evaluate relative material performance in case of damage. This review presents recent studies regarding mix design, fabrication methods, material incorporation, and experimental design to evaluate the performance of FAM mixtures. This study also summarizes the recent research findings on using micromechanical computational modeling and the correlation between the FAM and AC properties. It is the general consensus that microstructure of the FAM has a substantial effect on the mechanical properties and evolution of damage in AC. The main issue in the available literature is the detailed understanding of how FAM exists in the AC and how to replicate this for experimental purposes. This lack of understanding makes it to view the literature as disorganized information because each researcher employs his own method to study FAM materials. Therefore, there is a need to establish comprehensive fabrication and testing protocols as a specification to precisely resemble the FAM that exists within AC and hence accurately predict the performance characteristics of AC.
PubDate: 2021-11-01

• Evaluation of Natural Building Stones’ Characterizations Using
Ultrasonic Testing Technique

Abstract: Natural building stones are widely used in the construction field in the Middle East and Mediterranean areas. Stones are chosen for their durability, attractiveness, and low cost compared to other construction materials. Building stones come with different natural origins and vary in their mechanical and thermal characterizations. Compressive strength, water absorption, and thermal conductivity of the external walls are significant characteristics in evaluating the structure's durability and sustainability. External walls that are made of natural stones with high thermal conductivity lead to extensive use of energy and raise ongoing costs for cooling and heating. In addition, low compressive strength and high-water absorption adversely affect the long-term durability of natural building stones. This paper aims to establish in-situ evaluation models of compressive strength, thermal conductivity, and water absorption of natural building stones using the non-destructive Ultrasonic Pulse Velocity (UPV) testing technique. Laboratory experimental tests were conducted for ninety-nine specimens of eleven types of natural building stones with dimensions of 50 × 50 × 50 mm. Based on the obtained results, UPV values depend on the mechanical properties of building stones. Ultrasonic pulse velocities of the building stones are directly proportional to their compressive strength and thermal conductivity with a satisfactory correlated relationship. However, UPV values are inversely proportional to water absorption with a non-sufficient correlated relationship. The results emphasize that there are slight differences in the obtained values of compressive strength of natural building stones that are loaded parallel or perpendicular to the natural rift. The study found that Ultrasonic Pulse Velocity testing technique is an easy-to-use, economical, and non-destructive method for a preliminary prediction of the mechanical and physical properties of natural building stones. Compressive strength, water thermal conductivity, and water absorption estimation models are proposed for field evaluation of building stones based on the Ultrasonic Pulse velocities.
PubDate: 2021-11-01

• A New Model for the Prediction of Load Sharing in Piled Raft System—An
Experimental Investigation

Abstract: The complex load sharing mechanism between the raft and piles involving various interaction effects makes the piled raft system very popular and economic for the foundations of high-rise buildings around the world. This study highlights the outcomes of an experimental investigation on piled raft foundation under vertical load to establish a new method for estimating the loads shared by the piles and raft using the interaction factors and the stiffness values of unpiled raft and pile group. From the results, the pile-raft interaction factor $$\left( {\lambda_{{{\text{p}} - {\text{r}}}} } \right)$$ is found to decrease initially and then increase as the raft settles further. However, the raft-pile interaction factor $$\left( {\lambda_{{{\text{r}} - {\text{p}}}} } \right)$$ is observed to increase initially and then decrease indicating a positive influence of raft-pile interaction on the load response of piles. The piled raft coefficient (αPR) is found higher, i.e., 0.83 initially and then converges to 0.51 when the raft settlement reaches a value equals to 10% of the raft width. The developed model is validated with the centrifuge test data available in the literature. Simplified expressions to calculate various interaction factors and the piled raft coefficient are also proposed on the basis of the experimental results.
PubDate: 2021-11-01

• Failure Characteristics of Obliqued-layers Shale Specimens from
Experimental Observation

Abstract: Understanding the cracking characteristics of shale is necessary for oil and gas exploitation engineering. The cracking behaviours and failure modes of obliqued-layers shale specimens were studied under uniaxial compression stress. The acoustic emission response was monitored, and the displacement and strain fields were calculated with digital image correlation (DIC). For the flawed shale specimens, the cracks initiated from the flaw tips most of the time and propagated towards the boundaries, and bedding layers led to the branching and diversion of the crack path. The first cracks did not always start from the flaw tips due to microstructure distribution. Tensile cracks dominated the cracking process, and shear cracks mainly contributed to the final failure of the flawed shale specimens. The failure modes remained unchanged when the flaw rotated from 30° to 60°. However, shear cracks along the bedding layers and tensile cracks parallel to the maximum principal stress dominated the failure of the intact shale specimen. The flaw controlled the location of cracking initiation, and the bedding layers affected the cracking path for the flawed specimen. The bedding layers also control the failure mode of the intact specimen. The experimental results contribute to the understanding of cracking properties in layered anisotropic materials.
PubDate: 2021-11-01

• Investigations on Mechanical Characteristics and Microstructural Behavior
of Laterized High Strength Concrete Mix

Abstract: The present research focuses on the varying proportion of lateritic fine aggregates in High strength concrete (HSC). Concrete mixes of M60 grade were produced by replacing manufactured sand with laterite in the ratio of 25 to 100 percent (by weight), and properties of the mixes are studied. To attain high strength mix, 10% micro silica and 10% of fly ash (FA) were added to all mixes. Mechanical properties were studied after 7, 28, 56, and 90 days of curing, and laterized specimens achieved approximately 12 percent higher compressive strength than control specimens, whereas the split-tensile and flexural strengths increased up to 11.14% and 12.83%, respectively. The results indicated that 25% substitution of laterite was the optimum percentage in HSC concrete. Microstructural studies of optimum mix and reference mix were conducted at 28 days to better morphological and mineralogical understanding of the laterized HSC. Durability parameters such as water penetration depth, chloride ion permeability, and sorptivity exhibited higher values for laterite mixes than the control mixes. The flexural behavior of Reinforced HSC beams using lateritic aggregates was investigated, and the load-carrying capacity of laterized beams was reported to be 11.3 percent higher than control beams. The study results indicate that HSC can be achieved with partial substitution with lateritic fine aggregates and proves that laterite can replace conventional aggregates.
PubDate: 2021-11-01

• Impacts of Maltene on the Wettability and Adhesion Properties of
Rejuvenated Asphalt Binder

Abstract: In recent years, the use of reclaimed asphalt pavement (RAP) has gained much attention and is widely accepted. However, the rejuvenating agents which are usually used to reduce the rigidity of the aged asphalt are subjected to diverse climate circumstances. The present work used maltene as a rejuvenator to investigate several measurements regarding stripping failure. The evaluation of wettability and work of adhesion (WA) was assessed using the sessile drop method. Meanwhile, asphalt and asphalt-water aggregate systems were tested for acid and water resistance using chemical and water immersion tests. Next, atomic force microscopy (AFM) was used to evaluate the changes in the microstructures of the asphalt binders. The experimental results revealed that the ideal percentages of maltene which should be added to 30% and 50% aged asphalt were 8% and 16%, respectively. Meanwhile, the wettability, WA and resistance to stripping differed depending on the percentage of aged asphalt in the blend. However, the inclusion of maltene has improved samples containing high percentages of aged asphalt. On the other hand, the resistance to boiling water containing acid decreased slightly with the addition of maltene. Nevertheless, all the rejuvenated samples exhibited better results than virgin asphalt. Moreover, the AFM results were in line with the observations, suggesting the suitability of maltene for the functional application of pavement.
PubDate: 2021-11-01

• Structural Performance of Reinforced Concrete (RC) Moment Frame
Connections Strengthened Using FRP Composite Jackets

Abstract: This study investigates structural behaviors of reinforced concrete (RC) moment frame connections strengthened using three different FRPs with different cross section configurations. The novelty of this research is the strengthening of a beam–column connection with FRP composites, where the joint consists of a weak column and a strong one that plays a vital role in the RC element. It is also rare in engineering to use inorganic composites in retrofit configurations (X shape, U shape, and T shape retrofit configurations). That is why we aimed to apply fiber-reinforced composite materials in different configurations (cross, diagonal, and parallel configurations). The experimental performance of strengthened samples was investigated using carbon fiber-reinforced polymer (CFRP), aramid fiber-reinforced polymer (AFRP), and glass fiber-reinforced polymer (GFRP) under loading systems. The strengthened RC specimens (SBWC-2—SBWC-7) were compared with a control specimen (SBWC-1) in terms of load capacity, ductility index, failure modes, and crack patterns. The strengthening of the SBWC-2 and SBWC-3 specimens using CFRP increased the ultimate loads up to 12.5% and 11.4% compared to reference sample, respectively. The first cracks in SBWC-4 and SBWC-5 beam–column joint specimens were found at loads of 35.4 kN and 33.8 kN, respectively. The results indicate that SBWC-2 specimen strengthened by AFRP displayed higher strength and ductile behavior than other specimens, as it depends on failure mode more than its counterparts. The reinforced X shape beam–column connection sample was protected from diagonal cracks. Strengthening with CFRP decreased visible-width shear cracks compared to control samples. The experiments revealed that CFRP composites could be a suitable alternative for greatly improving structural performance and providing suitable and reliable solutions for sustainable structures.
PubDate: 2021-11-01

• Numerical Investigation on Static Behaviour of Steel- and GFRP-Reinforced

PubDate: 2021-11-01

• Experimental Analysis of the Behavior of Composite Column-Reinforced
Concrete Beam Joints

Abstract: This study assesses the seismic performance of steel-reinforced concrete (SRC) composite columns connected to reinforced concrete (RC) beam joints, and their ability to dissipate seismic energy through inelastic deformations. In this article, experimental aspects regarding the seismic performance of high-ductility and low-ductility steel–concrete composite frame were investigated. The principle design parameter in this study was ductility, which is considered a conceptual framework in Efficiency-Based Seismic Engineering. Thus, attention was focused on assuring various ductility ranges of joints obtained through a detailed study of the Turkish Earthquake Code (TEC 18) [Ministry of Public Works and Housing.: Türkiye Bina Deprem Yönetmeliği (Turkey’s Earthquake Code for Buildings). Official Gazette (2018) (in Turkish).]. After identifying deficiencies and the energy dissipation capacity in the newly proposed joints, two half-scaled frames with specific ductility-related designs were constructed, instrumented, tested, and analyzed. The specimens were tested under displacement-controlled lateral cyclic loading that incorporated constant axial loading to create cyclic tension and compression facets across the joint areas. The test results proved that the SRC column-RC beam frames employing an extra column reinforcement ratio exhibit slightly better seismic performance. Due to the presence of structural steel, the shear failure of the joint was effectively prevented, even after the formation of the plastic hinge on the interface of the beam. During the testing, the column rebars, to some extent, made a minor contribution to the joint strength of the specimen compared to the structural steel that absorbed almost all of the load applied to the frame.
PubDate: 2021-11-01

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