بررسي عملكرد قطر بهينه الياف پلي پروپيلن در رفتار مكانيكي روسازي بتن غلتكي

In recent years, the use of roller-compacted concrete pavement has significantly increased due to its numerous advantages. However, issues such as high stiffness, low tensile strength, and limited flexibility of roller-compacted concrete have led researchers to explore various modifiers to improve the properties of this type of pavement. In this study, the physical and mechanical properties of roller-compacted concrete modified with polypropylene fibers were investigated and compared using compressive strength, modulus of rupture, tensile strength (Brazilian test), and modulus of elasticity tests. The aim of this research is to eva‎luate the effect of polypropylene fiber diameter on the mechanical properties of roller-compacted concrete. For this purpose, four types of polypropylene fibers with four different diameters (0.1, 0.4, 0.5, and 0.7 mm) were used to improve the mechanical and physical properties of roller-compacted concrete pavement. The use of polypropylene fibers in the roller-compacted concrete mix had various impacts on its mechanical properties. The results showed improvements in compressive strength, flexural strength, and fracture energy of the concrete, while a negative impact on tensile strength and modulus of elasticity was observed in the samples containing polypropylene fibers. Overall, the appropriate selection of the type and percentage of polypropylene fibers can significantly enhance the mechanical properties of roller-compacted concrete, thereby increasing the lifespan and performance of concrete pavements. Considering the overall results obtained and the importance of flexural strength in concrete pavement design, Kortta Aqua fibers with a diameter of 0.5 mm had the most positive impact on the properties of roller-compacted concrete, with an improvement of approximately 100% in flexural strength and an increase of about 298% in fracture energy.

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