The permanent deformation of flexible pavement represent serious problem in hot climate region. Numerous efforts are devoted to mitigate this distress such as modifying asphalt binder by polymers. The present study demonstrate the effect of utilizing four types of polymers to reduce the permanent deformation, these polymers are Polyethylene Wax (PEW), Styrene Butadiene Rubber (SBR), Ethylene Propylene Dien Monomer (EPDM) and Ethylene Vinyl Acetate (EVA). The prepared mixtures composed of 4.9 % of 40/50 asphalt binder, 12.5 mm nominal aggregate maximum size and limestone dust as filler. The permanent and resilient strains have been recorded when the cylindrical specimens, 101.6 mm in diameter and 203.2 mm in height, tested by repeated loading system. The main conclusions exhibit that SBR and EPDM with the same concentration (15 % by weight of asphalt binder) reduced the permanent deformation by 30.20 % and 30.46 % respectively. Although, the PEW and EVA reduced permanent deformation by lower values, 13.24 % and 17.35 % respectively, but the incremental percentage of their action are higher. The influences of testing temperature and stress level on permanent deformation were investigated. Linear regression model was established to correlate the values of permanent deformation and the resilient modulus of asphalt mixtures.
Films of pure Poly (methyl methacrylate) (PMMA) doped by potassium iodide (KI) salt with percentages (1%) at different thickness prepared by casting method at room temperature. In order to study the effect of increasing thickness on optical properties, transmission and absorption spectra have been record for five different thicknesses(80,140,210,250,320)µm. The study has been extended to include the changes in the band gap energies, refractive index, extinction coefficient and absorption coefficient with thickness.
This study investigates the characterization and mechanical performance of Stone Mastic Asphalt (SMA) mixtures modified with two types of polymers: styrene–butadiene–styrene (SBS) and high-molecular-weight polyethylene (PE). Neat asphalt cement PG 64-16 was modified using a higher content of SBS and PE at concentrations of 6%, 7%, and 8% by weight of asphalt through the dry blending method to produce Highly Modified Asphalts (HiMA). The physical and rheological properties of the modified binders were evaluated using penetration, softening point, rotational viscosity, and dynamic shear rheometer (DSR) tests. Also, their phase compatibility and morphological changes were evaluated using the storage stability testing and scanning electron
... Show MoreBackground/Aim: The timing of a tooth's eruption can be affected by a variety of factors. The nutritional status has an impact on the development of a child's body. The purpose of the study was to analyse the number of children aged 6 to 9 in an Iraqi Arab population who had erupted permanent first molars and to examine how nutritional status affected the timing and level of emergence. Methods: A total of 330 boys and girls, in first grade elementary school, made up the sample. First molars that had erupted were noted, along with the level of the eruption. Each child's nutritional status was evaluated by recording their height and weight and body mass index (BMI) value was compared to the 2007 WHO reference. Results: Girls had highe
... Show Moreالهدف من الدراسه تحضير فئه جديده من بوليمرات السليكون P1-P4 والتي تمت على اساس استحدام ثنائي مثيل ثنائي كلورو سيلان((DCDMS مع بعض المركبات العضويه التي تحتوي مجاميع الهيدروكسيل الطرفيه والتي حضرت لاول مره M1-M4، بأستخدم البلمره التكثيفيه .كما تم تحضير متراكباتها النانويهP′1-P′4 بوجود جسيمات الفضه النانويه (Ag-NPs) باستخدام طريقة صب المحاليل. شخصت جميع التراكيب للمونمرات والبوليمرات المحضره باستخدام مطيافية
... Show MoreMicro metal forming has an application potential in different industrial fields. Flexible tool-assisted sheet metal forming at micro scale is among the forming techniques that have increasingly attracted wide attention of researchers. This forming process is a suitable technique for producing micro components because of its inexpensive process, high quality products and relatively high production rate. This study presents a novel micro deep drawing technique through using floating ring as an assistant die with flexible pad as a main die. The floating ring designed with specified geometry is located between the process workpiece and the rubber pad. The function of the floating ring in this work is to produce SS304 micro cups with profile
... Show MoreLinear motor offers several features in many applications that require linear motion. Nevertheless, the presence of cogging force can deteriorate the thrust of a permanent magnet linear motor. Using several methodologies, a design of synchronous single sided linear iron-core motor was proposed. According to exact formulas with surface-mounted magnets and concentrated winding specification, which are relying on geometrical parameters. Two-dimensional performance analysis of the designed model and its multi-objective optimization were accomplished as a method to reduce the motor cogging force using MAXWELL ANSYS. The optimum model design results showed that the maximum force ripple was approximatrly reduced by 81.24%compared to the origina
... Show MoreTo decrease the impact on the environment of building waste, the recycled aggregate may be used in various sustainable engineering applications, such as roller compacted concrete pavement (RCCP). This research examined how using recycled aggregate as a partial replacement for natural aggregate as coarse or fine affected the mechanical properties of roller-compacted concrete pavement. The recycled aggregate was crushed and sieved to coarse and fine aggregate before being used in the roller-compacted concrete pavement. Compressive strength, splitting tensile strength, and flexural strength were all evaluated after the samples were prepared at 28 and 90 days of curing. According to the study's findings, the partial replacem
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