نوع مقاله : پژوهشی اصیل (کامل)
کلیدواژهها
موضوعات
عنوان مقاله English
نویسندگان English
AbstractIn recent years, many studies have been conducted on the mechanical properties and durability of fiber concrete. These types of concretes are used in the reinforcement and repair of high-rise structures. In this study, the effect of mixing fiber concrete with 1 to 6% of additives including E207 and polycarboxylate ether separately with polypropylene fibers using durability tests including bulky water absorption tests, electrical resistance, rapide chloride penetration (RCPT) as well as compressive strength of concrete have been investigated. In addition, to study the microstructure of cement paste containing polypropylene fibers and polycarboxylate ether additives and E207 additive, X-ray diffraction (XRD) spectroscopy scanning electron microscopy (SEM) and X-ray chemistry tests were used. The results show that with the addition of polycarboxylate ether and polypropylene fibers (sample A) the permeability of chlorine ion in the samples was reduced uniformly so that the maximum reduction in chloride permeability in sample A was 51% while The addition of E207 additive and polypropylene fibers (sample B) reduced the permeability of chloride in concrete by 35% compared to the control sample. On the other hand, by adding additives A and B in the mixing design, the water absorption of concrete in samples A decreased by 27% and in samples B, 21% compared to the control sample. Also, the addition of polypropylene fibers in the amount of 0.6 kg/m3 reduced the electrical resistance of concrete in the samples by 5% compared to the control sample. The electrical resistivity in samples A increased by 213% and in samples B by 268% compared to the control sample. Compressive strength in samples A increased by 134% and 56% compared to the control sample of 7 and 28 days, respectively. And the highest compressive strength in B samples at 7 and 28 days of age increased by 38% and 39% compared to the control sample, respectively. In addition, by adding E207 to sample B, the compressive strength of the samples was reduced by more than 4%. Also, the results of SEM experiment showed that by adding polycarboxylate ether additive and E207 additive to the concrete microstructure concrete mix design, both samples were more homogeneous and dense than the control sample. The water apsorbtion less aligned .The results of XRD and XRF experiments on the samples showed that by adding polycarboxylate ether and E207 additives to the samples, more calcium silicate gel was formed and the aggregate pores were more cohesive and cohesive than the control sample, which confirms the results. Compressive strength test of concrete. According to the mentioned results, it can be concluded that with the addition of polycarboxylate ether and E207 additives, the durability and compressive strength of fiber reinforced concrete with polypropylene fibers are significantly increased against aggressive factors and concrete structures in the design. Mix concrete using additives according to this research. They will have a longer life and greater resistance to the aggressive agents of concrete structures, especially chloride, which will be economically viable in large projects
کلیدواژهها English
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