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Go to Editorial ManagerFused deposition modeling (FDM) is a commonly used 3D printing technique that involves heating, extruding, and depositing thermoplastic polymer filaments. The quality of FDM components is greatly influenced by the chosen processing settings. In this study, the Taguchi technique and artificial neural network were employed to predict the ultimate tensile strength of FDM components and establish a mathematical model. The mechanical properties of ABS were analyzed by varying parameters such as layer thickness, printing speed, direction angle, number of parameters, and nozzle temperature at five different levels. FDM 3D printers were used to fabricate samples for testing, following the ASTM-D638 standards, using the Taguchi orthogonal array experimental design method to set the process parameters. The results indicated that the printing process factors had a significant impact on tensile strength, with test values ranging from 31 to 38 MPa. The neural network achieved a maximum error of 5.518% when predicting tensile strength values, while the analytical model exhibited an error of 19.376%.
A tack coat is a minimal coating of asphalt cement, cut-back asphalt, or asphalt emulsion to an existing pavement surface between layers to guarantee proper bonding between the two layers and longitudinal and transverse joints. Numerous researchers have assessed interlayer adhesion employing failure-mode behavior tests, such as pull-off, direct shear, and torsion testing. This study aims to quantify the best tensile resistance obtained using three types of cutback asphalt (RC70, RC800 modified with polymer 4.5% & MC70). All are applied on concrete surfaces at a rate of 0.5 L/m². The Proceq DYNA Z16 pull–off tester is used to measure the tensile strength at a rate of 0.25 kN/s. It is found that the average tensile strength of the tack coat materials is (0.319, 0.138, 0.028) MPa, respectively. It is concluded that RC70 has the maximum tensile strength. Also, the different types of solvent affect adhesion strengths; RC70 was Prepared using gasoline, while MC70 used petroleum. Gasoline has greater volatility and thus increased adhesion. Failure strength modes of interior bonding varied between cohesive failure adhesive and adhesive failure.
Moisture-induced damage in asphalt pavements, is defined by adhesive failure at the binder-aggregate interface and decreased mechanical integrity, severely reduce pavement durability. The research examines the mechanical properties and moisture sensitivity of hot mix asphalt (HMA) enhanced with styrene-butadiene-styrene (SBS) polymer and including reclaimed asphalt pavement (RAP). Laboratory assessments, including indirect tensile strength (ITS) and tensile strength ratio (TSR) tests, were performed on conventional HMA, SBS-modified HMA (4% SBS), and SBS-modified HMA contained 20% RAP. The results indicated that SBS modification significantly improved mechanical and moisture resistance properties, where unconditioned ITS specimens increased by 37.1% and TSR value enhanced by 13.5%. The incorporation of RAP decreased ITS value by about 21 % relative to pure SBS-modified HMA; nevertheless, the SBS+RAP combination still show higher ITS and TSR values than conventional HMA.
This paper focused on evaluating the effect of aggregate gradation and polymer modification on indirect tensile strength (ITS) and the static stiffness for hot asphalt mixtures. In particular, data from ITS tests have been processed to obtain stiffness measurements through the application of Hondros theory. The results showed that fine mixtures had a better tensile strength by 26.3% than the coarse mixtures. The effect of compaction also was examined, the results showed that samples compacted with the Superpave gyratory compactor (SGC) had an enhancement in ITS by 36.58 and 23.1% in comparison with Marshall and roller compactor respectively. Polymer modifiers were used to estimate their effect on tensile strength, adding 4, 6, and 8% of Styrene-Butadiene-Styrene (SBS), which can rise the ITS by 3.2,6.14 and 13.3% of the non-modified asphalt mixture. Furthermore, using 4, 6, and 8 percent of SBS could increase static stiffness by 53.9, 209.6, and 302.4% respectively for roller compacted fine mixes and 58, 220, and 379.3% for SGC compacted mixes. Furthermore, SBS raised the stiffness modulus by 52.3, 188, and 295% for Marshall compacted mixes. Using hybrid modifier can improve the stiffness of the asphalt mixture. However, The results indicate that using 1, 2 and 3% polyvinyl chloride (PVC) can magnify the stiffness of mixtures by 41.2, 199.8% and 262.6 for roller compacted mixtures and 133.4, 212.1 and 354% for SGC compacted mixtures, whereas there is a stringent increasing by 133.4, 189.2 and 354% for Marshall compacted mixes. Otherwise, polymer-modification can decrease the fracturing index for coarse and fine mixtures.
Normal concrete is weak against tensile strength, has low ductility and also insignificant resistance to cracking. The addition of diverse types of fibers at specific proportions can enhance the mechanical properties as well as the durability. Discrete fiber, which is commonly used, have many disadvantages such as balling the fiber, random distribution, and limitation of the used Vf ratio. Based on this vision, a new technique was discovered, enhancing concrete by textile-fiber to avoid all the problems mentioned above. This paper presents all important consequence and conclusions obtained from previous studies on how to strengthen concrete with two-dimensional and three-dimensional textile-fibers, and focuses on the flexural behavior of concrete members. The results indicate that there was an improvement in flexural strength, deformation capacity, and toughness with different load conditions when using different types of textile-fiber. It was observed that the effect of textile-fibers would increase when this fiber was coated by epoxy. In TRC system, there is a significant impact on the number of textile-fiber layers used.
The purpose of this research is to investigate how the fiber orientation and loading axis of a composite material affect its behavior. Consideration was given to two different fiber-to-matrix ratios in order to improve the mechanical properties. Hand lay-up samples were produced in accordance with ASTM D790 for flexural testing. On UTM, tensile and flexural tests were performed on the sample. The effect of fiber orientation modifies the composites' mechanical properties. As the fiber orientation increased, the tensile strength of the composite would reduce. This carbon/epoxy composite test demonstrates better strength than those conducted at (30, 5, 60, and 90 degrees). For flexural tests, a three-point bend at 30 degrees demonstrates excellent strength. Utilizing the three-point bend method, the flexural strength and flexural modulus have been determined. The tensile strength, young's modulus, elongation percentage, maximum load to break the composite, peak load, and flexural strength of single- and double-layered carbon fibers were compared and examined. As the number of layers increased, the adhesion between layers of epoxy and fiber carbon, and glass fiber weakened, causing a decrease in almost all mechanical properties. The fabricated 2024-T3 and epoxy glass fiber had higher fatigue strength than aramid reinforced and lower density than steel alloy utilized in aircraft manufacture.
Hot mix asphalt embedded on "Reclaimed asphalt pavement"(RAP) has the advantages of high technology. Moisture damage is a concern in these mixtures at all service temperatures. Therefore, the performance of this mixture against moisture at all service temperatures was considered a target of this research study. In this way, the effects of humidity on the performance of varieties were investigated using experimental methods including tensile strength ratio (TSR). In the framework of this study, Four different ratios of RAP for each of the surface and bonding layers (10%, 15%, 20%, 25%) and (30,40,50,60)% were added to the hot asphalt mix (HMA) for the two layers respectively to study and find the content Optimal RAP for both layers RAP through Marshall stability and hygroscopic resistance of asphalt mixtures through moisture damage is examined. The ratio (TSR) of the mixtures containing the optimal RAP content is compared with the asphalt mixture without RAP for three fillers and for both layers. The results showed a slight decrease in the tensile strength of the (HMA) that does not contain RAP compared to the asphalt control mixtures containing the reclaimed pavement, where it was found that the percentages were slightly higher and still higher than 80%. The results indicate that in general, Although there are old materials in the hot asphalt mix (HMA) produced from RAP, which include aggregates and bitumen binder surrounding the aggregate particles, the performance of these mixtures and integrations against moisture damage. Because it contains this, it can have results with “hot asphalt mixtures” containing RAP for areas with damage without worry in addition to good natural curbs.
The effects of the repeated solution heat treatment on hardness, tensile strength and microstructure of aluminum were investigated. For this purpose, an alloy of AA6061-T6 was undergo to cyclic solution heat treatment process which is composed of repeated period (10 min) held at 520 °C for 1, 4, 8 and 12 cycles. The hardness was tested for five aging times (as quenching, one week, three weeks, one month and five months) to all cycles (1, 4, 8 and 12) firstly and it is found that the hardness of five months as aging time for all cycles has the best results (90Hv) as compared with others (as quenching, one week, three weeks, and one month), so it was adopted for all cycles to implement the tensile test and the microstructure. Hardness results were improved to Vickers hardness of (90Hv) with increasing of cycles up to 8 cycles then decreasing after that to (45Hv). Tensile results were showed an increment (34%) also for the same group of 8 cycles compared with (17%) and (9%) for 4 and 12 cycles, respectively. Microstructure is revealed that whenever cycles are increased, the precipitate phase in alloy is increased also, thus, it is improved the hardness and tensile strength.
The aim of this work is to investigate the effect of soil corrosion on the critical buckling load of circular columns made of 2014-T4 aluminum alloy. In this work, 24 specimens were used and buried in the soil for 120 days. The samples divided into two groups (12 columns with corrosion before shot penning (SP) and ultrasonic impact treatment (UIT), and 12 columns with corrosion after combined surface treatments (SP+UIT)). The experimental1results revealed1that the corrosion negatively1affects the mechanical properties1of the material, and the1reduction percentage (R%) for1ultimate tensile strength (UTS) and1yield strength (YS) was (1.95% and 4.57%) respectively. After combined surface treatments (SP+UIT) for the corroded columns, the ultimate1tensile strength (UTS) and yield1strength (YS) were improved with (2.42%, and 2.87%) respectively. Perry-Robertson, Rankine, and ANSYS were used to estimate the critical buckling load (Pcr) and compare it with the experimental results. Rankine and Perry's formulas have been achieved a good agreement with the experimental without and with (1.5) factor of safety respectively. While ANSYS gave satisfactory prediction with a safety factor of (2.2, and 2.7) and (1.9, and 2.7) for long and intermediate columns before and after (SP+UIP) respectively.
Biodegradable polymers are very useful polymers in biomedical applications. In this research, several hydrogels were fabricated by using two polymers, Polyvinyl alcohol (PVA) and Chitosan (Chs) by the solvent casting method in order to use them for skin applications. Several tests were carried out on these membranes such as Agar diffusion method to examine their antimicrobial activities, Fourier transform infrared microscopy (FTIR) test to study the differences in their chemical structures. Uniaxial tensile test was performed to examine the mechanical characteristics of these membranes. In addition, the wettability test was used to investigate the hydrophobicity or hydrophilicity of the surfaces. The results showed that all membranes are hydrophilic, of which the contact angles are less than 90°. The membrane manufactured from 75:25 Chs-PVA is more hydrophobic (contact angle is 74°) than other membranes made of 50:50 Chs-PVA and 25:75 Chs-PVA as the contact angles were 59° and 61°, respectively. The tensile test results indicate that the membrane fabricated of the PVA and the membrane that was fabricated by 75% Chs and 25% PVA has the highest tensile strength of 17.9 MPa, 16.2 MPa and Young^’ s Modulus of 181.2 MPa and 7.18 MPa, respectively. The highest strain at break was observed by the membrane of 25:75 Chs-PVA which equals to 24.67%. Chitosan membranes showed inhibition zones of about 2.99 cm and 2.75 cm in length, and 75:25 Chs-PVA membranes showed 5.1 and 5.91 cm in length for E.coli. To sum up, this copolymer is considered as promising hydrogel for skin applications such as wound dressing.
Reflective cracking is a serious issue that Adversely influences the performance and longevity of asphalt overlays over deteriorated pavements. This review Looks for the Technologies which used to reduce the reflection cracks propagation by insert a new Strategies and different design materials. This research dealt with many treatments such as: increasing the layer thickness of Hot Mix Asphalt (HMA), creating modified asphalt by adding polymers to asphalt, rubberizing asphalt, carbon black, sulfur and other different materials. Geosynthetic materials were studied and analyzed to evaluate their ability to increase the layer tensile strength and minimize the effect of reflection cracks such as geotextiles, geogrids, and Stress Absorbing Membrane Interlayers (SAMI). The research shows that the increasing of overlay asphalt layer thickness leads to durability development. On the other hand, using developed materials like Polymer-Modified Asphalt and Stress Absorbing Membrane Interlayers (SAMI) Strategies leads to increasing the service life of the repaired pavement. The conclusion indicated that the development of overlay asphalt layer thickness and layer reinforcement and applying advanced environmental systems can be improving the pavement performance. These Strategies can produce a perfect solution to prevent or reduce the reflection cracks in rigid and flexible pavement.
Utilization of additives can be an effective way to improve the durability and performance of HMA, making them more resistant to Moisture and deformation. Plus, they can reduce the need for maintenance and repairs, saving you time and money in the long run. In this study, CKD was used in place of limestone as a filler in the asphalt mixture in proportions of 0%, 25%, 50%, 75%, and 100%, and polymer SBS 4%by weight of asphalt. According to the findings, replacement-content CKD had the highest asphalt content. When the CKD is between 25% and 50%, Stability, Flow, and Indirect Tensile Strength are improved, while the density of the asphalt mixture decreases and the amount of air voids increases at higher ratios. While SBS leads to an increase in the hardness of the adhesives. As a consequence, the stability of the SBS-containing mixes resulted in higher values than the control and additive-containing mixtures (CKD), as well as a decrease in the number of air voids. According to the results, CKD should not constitute more than half of the filler weight in the asphalt mixture.
Structural elements. This means the structural behavior can be quantified by considering the behavior of each structural element in each load path. Concrete is a material known for its great strength. Regardless, there are a few weaknesses, which must be taken in consideration in the design of concrete structural elements. Basically, concrete is made of three main ingredients: Portland cement, water, and aggregates (sand and stone).In order to improve tensile strength and ductility (capacity to stretch and deform prior to failure) in concrete, so this paper discus some types of concrete and record the effect on beams. Reactive powder concrete (RPC) is an actual concrete mixture, it is a special type of concrete because mix concrete (coarse and fine aggregate ) replaced by fine sand size (150-400)µm. In the experimental comparison the mechanical properties( compressive , splitting tensile and flexural )strength of plain RPC and high and normal strength concrete. Each set consisted of (4) cubes of (100×100×100_mm, (8) cylinder of (150×300mm) and (4) prism of (100x100x500) mm and consisted of (4) beam of (1000×100×400)mm. The results shown that the maximum compressive strength is 107 MPa and the maximum splitting tensile 9 MPa of RPC comparison high and normal strength concrete. The result of the second part shown increased RPC reinforced concrete the firstcrack288 MPa and ultimate crack 380MPa comparison high and normal strength concrete and the mode of failure of RPC (flexural-shear).
This research studies the physical and mechanical properties of mortar composed of PVC plastic waste particles used as fine aggregate replacement material. PVC particles in quantities of 5%, 10%, 15%, 20%, 25%, and 30% by volume were used for sand fraction substitution. This quantity of PVC was used to formulate seven mixes with a cement content of 525 kg/m3 and a water-to-cement ratio (w/c) of 0.45. At 7 and 28 days, the compressive and splitting tensile strengths of the mortar's mechanical characteristics were evaluated. Additionally, the physical characteristics of density and absorption were investigated. The findings demonstrated that the mechanical properties and density of mortar containing PVC powder were minimized.
Open graded asphalt mixture is becoming more widespread where it is applied for various purposes, e.g. drainage of rainwater effectivity, traffic safety (high skid resistance), and controlling pollution noise. However, it has many other disadvantages, of which low stability, high stripping, and moisture sensitivity. The research aims to study the effect of styrene butadiene styrene SBS addition on the volumetric and mechanical properties of open graded mixture. In this research one type of aggregate with gradation (12.5 mm NMAS), asphalt of penetration grade (40/50), and cement as filler were used. Optimum asphalt content was selected based on the criteria of air voids content, asphalt drain down, permeability, and abrasion resistance (for aged and un-aged) samples. Other properties of open-graded mixtures, such as indirect tensile strength (ITS), moisture susceptibility, Marshall stability and flow were evaluated. The results show that addition of polymer (SBS) leads to an enhancement in the properties of the modified mixtures. There is an improvement in Marshall parameters. Also, a slight decreasing is noticed for permeability and air voids. For Cantabro abrasion loss (aging and un-aging condition), the abrasion resistance is increased, the drain down of asphalt is decreased from original mixture by addition of SBS. Finally, the moisture sensitivity is improved indicating that modified mixes becomes more resistant to water damage.
The research includes studying the mechanical properties of BNTN/PAM nanocomposites under static and dynamic conditions. The BNTN/PAM nanocomposites were prepared with different weight fractions (0, 20%, 40%, 50% and 60%) by utilizing ball milling technique. Tensile strength, Charpy impact and Shore A hardness were performed to verify any improvements in these mechanical properties of nanocomposites. The results showed significant improvements in tensile, Charpy impact, Shore A hardness properties of nanocomposites at 50% weight fraction by approximately 335%, 1422%, 63% respectively. These results started decreasing after addition of 60% of nanoclays content to PAM composites. This mechanism indicates that the percentage of weight content of BNTN could affect the mechanical properties of nanocomposites.