Experimental programs based test results has been used as a means to find out the response of individual elements of structure. In the present study involves investigated behavior of five reinforced concrete deep beams of dimension (length 1200 x height 300 x width150mm) under two points concentrated load with shear span to depth ratio of (1.52), four of these beams with hallow core and
retrofit with carbon fiber reinforced polymer CFRP (with single or double or sides Strips). Two shapes of hallow are investigated (circle and square section) to evaluated the response of beams in case experimental behavior. Test on simply supported beam was performed in the laboratory & loaddeflection, strain of concrete data and crack pattern of those five reinforced concrete beams was recorded. Parametric studies are also conducted in this study includes the effect of hallow opening (shapes and materials), and CFRP ratio (single, double strips and side horizontal stirrups). Comparisons of test results from experimental data are based on load capacity, deflection, crack pattern and strain of concrete for all beams. From this comparison it was found that hallow effect on strength capacity i.e. decrease by about (13%) and increased in deflection and strain by about (18%, 24%) respectively compared with solid section. Also find that CFRP give more enhancements in loading capacity by about(33 to 66%) and decreased deflection for same applied load by about (26%). Test results that show when sides of beams retrofit with CFRP strip against horizontal shear increased strength by about by (20%). Finally the using double CFRP strips for hallow section gives equivalent or more than strength capacity of solid section.
An aromatic ester containing two azo groups namely p-nitro phenyl azo-β-naphthyl-(4'-azobenzoic acid)-4-benzoate was synthesized by esterfiaction of 4,4'-azo dibenzoic acid with p-nitro phenyl azo-β-naphthol. Synthesized ester was characterized by CHN-Elemental analysis, FTIR, 1H NMR and 13C NMR. A modified PVA polymer was obtained by grafting 10 g of PVA-polymer via partial esterification with (2, 3, 4 g) p-nitro phenyl azo-1-naphthyl-4-azobenzoic acid)-4-azo benzoate. Grafting PVA-polymer behaviours was studied, by physical measurements (solubility, swelling), thermal properties (DSC) and tensile.
Acrylic polymer/cement nanocomposites in dark and light colors have been developed for coating floors and swimming pools. This work aims to emphasize the effect of cement filling on the mechanical parameters, thermal stability, and wettability of acrylic polymer. The preparation was carried out using the casting method from acrylic polymer coating solution, which was added to cement nanoparticles (65 nm) with weight concentrations of (0, 1, 2, 4, and 8 wt%) to achieve high-quality specifications and good adhesion. Maximum impact strength and Hardness shore A were observed at cement ratios of 2 wt% and 4 wt%, respectively. Changing the filling ratio has a significant effect on the strain of the nanocomposites. The contact angle was i
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In this study, optical fibers were designed and implemented as a chemical sensor based on surface plasmon resonance (SPR) to estimate the age of the oil used in electrical transformers. The study depends on the refractive indices of the oil. The sensor was created by embedding the center portion of the optical fiber in a resin block, followed by polishing, and tapering to create the optical fiber sensor. The tapering time was 50 min. The multi-mode optical fiber was coated with 60 nm thickness gold metal. The deposition length was 4 cm. The sensor's resonance wavelength was 415 nm. The primary sensor parameters were calculated, including sensitivity (6.25), signal-to-noise ratio (2.38), figure of merit (4.88), and accuracy (3.2)
... Show MoreIn this work, a Photonic Crystal Fiber (PCF) sensor based on the Surface Plasmon Resonance (SPR) technology was proposed. A thin layer of gold (Au) was deposited on a D-shaped Photonic Crystal Fiber (PCF), which was coated with plasmonic chemically stable gold material with a thickness of 40nm. The performance parameters like sensitivity including wavelength sensitivity and amplitude sensitivity and resolution were evaluated by simulation using COMSOL software. The proposed sensor was created by using the finite element approach, it is numerically examined. The results show that the surface of D-shaped Photonic Crystal Fiber coated with Au behaves as a sensor to detect the refractive index (IR) of toxic metal ions. The impacts of the str
... Show MoreThe transfer of chemical pollutants from bottled water into water due to heat, sunlight and poor storage is one of the most serious threats to human health around the world, the objective of this study was to estimate the pH value and the transport of heavy metals from plastic bottles to water, for this purpose, 30 bottles of water for 10 local brands were collected and divided into three groups, the first was left at room temperature 25°C, The second was placed in a heat oven at 25°C and the third in another oven at 50°C for two weeks. The results showed significant differences at (P<0.05) between water samples, pH value and concentrations of heavy metals (Sb, Pb, Ni, Cu, Cr, Cd and Fe) we
... Show MoreAn experimental investigation based on thirty three simple pullout cylinder specimens was conducted to study the bond-slip trend between concrete and steel reinforcement. Plain and deformed steel reinforcement bars were used in this investigation. The effect of bar diameter, concrete compressive strength and development length on bond-slip relation was detected. The results showed that the bond strength increases with increasing of compressive strength and with decreasing of bar diameter and development length. A nonlinear regression analysis for the experimental results yields in a mathematical correlation to predict the bond strength as a function of concrete compressive strength, reinforcing bar diameter and its yield stress. The minimum
... Show MoreThis paper provides the result of an investigation to use of crushed clay brick as
aggregates in producing concrete. Eight different crushed clay brick aggregate concretes were
used in this investigation. Compressive strength, splitting tensile strength and pulse velocity of
crushed clay brick aggregates concrete were determined and compare to natural aggregate
concrete. The compressive strength of crushed clay brick aggregates concretes were always
lower than the compressive strength of natural aggregates concrete regardless the age of
concrete, but the crushed clay brick aggregates concrete showed better performance as the age of
concrete increases and average reduction in compressive strength were 33.5% at the age
Prediction of the structural response of reinforced concrete to the time-dependent, creep and shrinkage, volume changes is complex. Creep is usually determined by measuring the change, with time, in the strain of specimens subjected to a constant stress and stored under appropriate conditions. This paper brings into view the development of creep strain for four self-compacting concrete mixes: A40, AL40, B60 and BL60 (where 40 and 60 represent the compressive strength level at 28 days and L indicates to Portlandlimestone cement). Specimens were put under sustained load and exposed to controlled conditions in a creep chamber (ASTM C512). The test results showed that normal strength Portland-limestone mixes have yielded lower ultimate c
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