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Abstract
Research subject: In this research, epoxy modification was successfully performed by polyurethane and its effect on abrasion and adhesion properties have been investigated. The most important concern in the blending of these polymers was the formation of gels upon exposure of epoxy resin and isocyanate in polyurethane.
Research approach: One solution to overcome this problem is to control the chemical activity of Isocyanate. Therefore to reduce the chemical activity of isocyanate and prevent gel formation due to the combination of epoxy and polyurethane, first polyurethane prepolymer containing 3.58 wt.% NCO was prepared by mixing poly tetra methylene glycol 2000 (PTMG 2000) and toluene di isocyanate (2,4-TDI); and then by adding 20 wt.% of it to the epoxy resin, the curing process was completed by using dimethyl thio-toluene di amine (DMTDA) as a common curing agent and also specific heat treatment.
Main results: Fourier transformation infrared spectroscopy results showed that the modification process has been successful by elimination of the peaks related to epoxide and isocyanate groups in the prepared sample in addition to the formation of a broad peak related to secondary hydroxyl group (C-O) due to the opening of epoxide rings. Pull off tests also confirmed increasing adhesion to carbon steel substrate as a result of secondary hydroxyl generation through this blending. Although, the Persoz hardness of modified epoxy decreased by 5%, but with a 17-fold reduction of elastic modulus (as per tensile test result), abrasion resistance improved 6 times according to abrasion test. Finally, joining of the cavities to each other is introduced as the abrasion mechanism by considering the field emission- scanning electron microscope images.

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Today, in building structures, concrete shear walls are widely used due to their desirable ductility and high energy dissipation. The presence of openings in the concrete shear wall changes the behavior of the wall and also creates new members in the wall, so the presence of openings in the wall behavior is very effective. Among the components of shear wall are the base walls and interface beams. A connecting beam is a beam that connects two shear walls created by an opening. The base of the wall is the vertical part of the wall that is bounded between the opening and the edge. Therefore, in this study, the behavior of eccentrically open concrete shear walls that have been reinforced by steel sheets has been investigated. In this research, a sample of concrete shear wall with eccentric opening with the name of reference sample has been validated in ABAQUS software. According to the definition of ACI318-14, one wall base is in the dimensional range of the wall and the other is in the dimensional range of the wall base. The samples were reinforced using vertical, horizontal and diagonal steel sheets simultaneously (in RCSW15 to RCSW20 samples) and in them different parameters such as increasing bearing capacity, strength, hardness, ductility and energy dissipation were studied. . In the RCSW15 and RCSW16 models, only the reinforcement around the opening is done by vertical and horizontal steel sheets. In the RCSW17 sample, horizontal, vertical and diagonal sheets are used simultaneously. The RCSW18 uses horizontal and vertical sheets in the opening corner. In the RCSW19 model, horizontal and diagonal sheets are used to reduce strain on the heel of the wall. In the RCSW20 sample, reinforcement is performed by horizontal and vertical sheets in order to increase the bending and shear capacity. Sample loading is lateral and cyclic. Among the reinforced designs of RCSW20 sample, the best design was selected because this design increased the final strength of the structure by 127.3%, increased the maximum strength by 13.42% and increased the crack resistance by 22.53%. It also increased the amount of energy consumed by 16.8%.