نوع مقاله : پژوهشی
نویسندگان
1 استادیار دانشگاه آزاد اسلامی واحد سمنان
2 گروه مهندسی عمران، واحد سمنان، دانشگاه آزاد اسلامی، سمنان، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
The use of fibers is often aimed at increasing the ductility and load-bearing capacity of the desired concrete, and controlling the spread of cracks by adding fibers to the concrete causes this. The fibers improve the behavior of the concrete after the first crack due to the bridging property on the micro-cracks. In this paper, 15 concrete mixing designs in the form of 90 cubic specimens with dimensions (15 * 15 * 15) cm for compressive strength test and 42 specimens with dimensions (15 * 15 * 60) cm for flexural strength test have been made. 3 mixing designs were made as a reference with 3 water to cement ratios (0.24, 0.29, 0.34) without fibers and with fibers with 3 different lengths of polypropylene fibers with lengths of (6, 12, 18) mm, respectively. A mixing scheme with 40 mm long hook metal fibers and another mixing scheme with a combination of 40 mm hooked metal fibers and 12 mm polypropylene fibers were investigated. The highest 28-day compressive strength was related to the samples with composite fibers with a resistance of 76.16 MPa, which was 16.3% higher than the reference sample. Concrete specimens with metal fibers with a flexural strength of 16.1 MPa have the highest strength among all concrete mixing designs in this study and show a 60% increase in flexural strength compared to the specimen without fibers. In the concrete samples tested with polypropylene fibers, after the compressive strength test, with the increase in the length of the polypropylene fibers, the workability and compressive strength of the concrete decreased, but the plasticity of the concrete samples increased. After the flexural strength test, the flexural strength and ductility of the concrete samples increased with the increase in the length of the polypropylene fibers, but it led to a decrease in the workability of the concrete.
کلیدواژهها [English]
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