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This paper presents results of an experimental investigation involving eighttests on 1800mm long reinforced concrete (RC) beams strengthened in shear withexternally bolted carbon fiber reinforced polymer (CFRP) composites. The overallobjective of this study was to investigate the shear performance and failure modesof RC beams strengthened with externally fixed carbon FRP (CFRP) manufacturedU-warp strips and the specific goal was to keep the CFRP strips working till thebeam reaches its flexural failure because in most of the previous researches theCFRPs debonded from the concrete surface and the failure (separation) happenedin the concrete. The variables investigated within this program included: CFRPspacing and number of CFRP layers. The experimental results indicated that thecontribution of externally fixed CFRP strips to the shear capacity is significant anddepends on the variables investigated. In all the beam specimens (with endanchorage) the debonding was not observed.

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This research aims to study the influence of using Carbon Fiber Reinforced Polymer (CFRP) strips as an external strengthened and repairing material on the behavior of self-compacting concrete (SCC) Corbels. The experimental work involved testing twenty self-compacting concrete corbels specimens. The experimental work is divided into two parts; the first part consists of three groups to investigate the most effective direction, position, bonding type and amount of CFRP strips on the behavior of corbels and utilized it in practice, also to strengthen new variables that are investigated in the second part. Two groups in part one are strengthened with different numbers of inclined and horizontal direction of CFRP strips, while in the third group the specimens were strengthened with strips of CFRP having different directions and bond types to improve the strength capacity and behavior of corbels. This improvement is represented by increase cracking load by about (94)% and increase in their ultimate load capacity of strengthening corbels which varies from about (19 to 88)%. While the second part of experimental work included the following variables: shear span to effective depth ratio (a/d), amount of horizontal steel reinforcement stirrups and repaired damaged corbels. The reinforced concrete corbels in this part were strengthened and repaired by CFRP strips depending on optimum result that is produced from part one wherefrom position, direction and amount are considered. It was found for un-strengthened and strengthened corbels having same horizontal secondary reinforcement stirrups that when (a/d) ratio decreases from 0.65 to 0.4 causes increase in cracking and ultimate loads reach (55)% and (35.41)% respectively. For un-strengthened and strengthened corbels having same (a/d) ratio, it was found an increase in cracking load which varies from (6.66 to 34.78)% and from (18.18 to 52.63) % in ultimate load when horizontal secondary reinforcement stirrups are increased. It was also found repairing SCC corbels with CFRP strips causes an increase in ultimate load reaching up to (50)% with respect to un-strengthened specimens. From results it is concluded that strengthened or repaired corbels present stiffer load deflection response than corresponding un-strengthened corbel (control corbel).

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The effect of fiber volume fraction of the carbon fiber on the thermal conductivity of the polymer composite material was studied. Different percentages of carbon fibers were used (5%, 10%, 15%, 20%, and 25%). Specimens were made in two groups for unsaturated polyester as a matrix and carbon fibers, first group has parallel arrangement of fibers and the second group has perpendicular arrangement of fibers on the thermal flow, Lee's disk method was used for testing the specimens. This study showed that the values of the of thermal conductivity of the specimens when the fibers arranged in parallel direction was higher than that when the fibers arranged in the perpendicular direction
The results indicated that the thermal conductivity increases with the increasing the fiber volume fraction. Minimum value was (0.64 W/m.C) for parallel arrangement and (0.1715 W/m.C) for perpendicular arrangement at (Vf = 5%) .Maximum value for parallel and perpendicular were (2.65 W/m. C) and (0.215 W/m.C) at (Vf = 25%) respectively.

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Experimental investigations of the behavior of reinforced concrete three-span continuous beams with 1200 mm length for each span, with cross-section 120 mm width and 180 mm depth strengthened by CFRP in flexure case of beams have been presented. The experimental program consisted of nine RC beams, which were strengthened at some locations with CFRP laminates and carefully designed to fail in flexure. The results show that the use of external CFRP laminate connected to the beams could enhance the ultimate flexural load capacity up to 102.88%.

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In this work, elbow orthosis which represents one of the upper extremity orthosis is manufactured from two layers of polypropylene reinforced by a sheet of carbon fiber between them to construct a new composite material called "PCP" material. More flexibility is gained by minimization of the modulus of elasticity of polypropylene-carbon fiber- polypropylene to about 3.5 against old material. Average pressure is measured between the patient's arm and bicep part of elbow using a portable pressure device (has mat of sensors) which reach to about 217 kPa. ANSYS PACKAGE version 11 is used for numerical analysis the bicep part of elbow by using the estimated internal pressure to investigate deformation and to determine the Von – Misses stress. The investigated numerical results showed that the new material maximizes the deformation to about 280 % ( still in elastic region) and make the design more safe by increasing the factor of safety more than 4 % against polypropylene material. Mechanical properties are measured also in present work by carrying out the tensile test for the two materials under study to conclude finally that, the sheet of carbon fiber which is added has increased the mechanical properties to about 8.25 % and 248 % for yield and ultimate stresses respectively.

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The main objective of this work is to evaluate strength and behavior of reinforced concrete beams reinforced with discrete carbon fiber. Six beams were cast and tested up to failure under two concentrated static loads. Four beams were strengthened with discrete carbon fiber (two of them reinforced with carbon fiber of length 12mm and the other two with 6mm carbon fiber). The remaining two were casted without using carbon fiber as a reference beams. Load-deflection response of all the beams was evaluated. The effect of shear span to effective depth ratio and carbon fiber pecies length on the behavior of beams was studied. The results revealed a good improvement provided b the usage of carbon fiber as compared with the references beams (without carbon fiber). The results also show that. The use of carbon fiber lead to a good improvement in the ultimate load value [ (6mm) length carbon fiber increased (Pu) by 18.75% for (a/d = 4/3) and by 20% for (a/d = 4), while the (12mm) length carbon fiber increased (Pu) by 64.06% for (a/d = 4/3) and by 80% for (a/d = 4)].

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This paper reports a.c., d.c. conductivity and dielectric behavior of Ep-hybrid composite with12 Vol.% Kevlar-Carbon hybrid . D.C. conductivity measurements are conducted on the graded composites by using an electrometer over the temperature range from (293-413) K. It was shown then that conductivity increases by increasing number of Kevlar –Carbon fiber layers (Ep1, Ep2, Ep3), due to the high electrical conductivity of Carbon fiber. To identify the mechanism governing the conduction, the activation energies at low temperature region (LTR) and at high temperature region (HTR) have been calculated. The activation energy values for hybrid composite decrease with increasing number of fiber layers. The a.c. conductivity was measured over frequency range 100 Hz-1MHz. It was found that σ(ω) values increase with increasing frequency according to the relation σ (ω)=Aws . The values of frequency exponent (s) were found to increase with number of layers.

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In the present work the nickel metal matrix was developed by electrochemicalforming technique, were the nickel matrix is built around the reinforced carbonfiber in various thicknesses and fiber volume fractions. The metallographicanalysis indicate that the experimental depositing condition have a dominatingeffect on the observed composite microstructure. The grain size of the depositednickel is found (from the microstructure) to vary inversely with the amount of thedepositing electrical current density. Also the temperature of the solution seem toreflect quite well on the microstructure of the metal matrix, were relatively highand low solution temperature produced rather refined grain structure, while anintermediate temperature of (50°C) is found to deposited courser grain size.Secondary thermal and mechanical treatments are found to modify themicrostructure in a way that higher annealing temperatures tend to enhanced thegrain growth process and tend to reduced apparent porosity at (650°C), similarlythe forging of the electroformed composites made at different temperature tend toreduced the internal porosity, by a notable ratio, depending on the temperature ofthe forging process.

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Numerical analyses are performed using the ANSYS finite element program to simulate reinforced concrete beams strengthened by carbon fiber reinforced polymer applied at the bottom of these beams. Nonlinear material behavior, as it relates to steel reinforcing bars and plain concrete, and linear behavior for carbon fiber reinforced polymer is simulated using appropriate constitutive models. The results showed that the general behavior of the finite element models represented by the load-deflection curves at midspan show good agreement with the test data from the previous researches. Also The crack patterns at the failure loads from the finite element models correspond well with the observed failure modes of the experimental beams. The Finite element models represented by this research can be used to work parametric study for the strengthening of beams with CFRP.

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This research is devoted to investigate the effect of Carbon Fibre Reinforced Polymer (CFRP)strips on the behaviour and load carrying capacity of strengthened and repaired reinforced concretecorbels. Experimental investigation were carried. The experimental program variables includelocation, direction, amount of CFRP strips and effect of shear span to effective depth (a/d) ratio onthe behaviour of strengthened corbels. All corbels had the same dimensions and flexuralreinforcement and they were without horizontal shear steel reinforcement. The experimental resultsobtained from the adopted strengthening and repairing CFRP techniques showed a significantimprovement in the behaviour and carrying capacity of the tested corbels. An increase of about (44.5- 60) % in the ultimate load has been obtained for specimens strengthening by inclined techniquecompared to the ultimate load of control corbel and (14.7 - 31.2)% for specimens strengtheninghorizontal technique. For corbels repaired with CFRP strips, an increase of (56%) with respect to theultimate load of control corbel is achieved. Also the strengthened corbels show stiffer load deflectionresponse than corresponding control corbels (unstrengthened corbels).

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