Torsion Behavior Of Recycled Aggregates Concrete Beams With Openings /
سلوك اللي للكمرات الخرسانية ذات الفتحات و المصبوبة بالركام المُعاد تدويره
By Yahia Mohy El-Deen Mostafa Osman ; Under the Supervision of Prof. Dr. Hany Ahmed Abdalla, Dr. Ashraf Adel Shwky.
- 66 pages : illustrations ; 30 cm. + CD.
Thesis (M.Sc.)-Cairo University, 2022.
Bibliography: pages 65-66.
Due to the fast rise in material and transportation costs, the recycling of construction waste has become a critical operation in the construction industry. With the rise in construction and demolition operations in the construction sector, the relevance of this process has grown even more. Furthermore, the environmental risks associated with rising carbon emissions have made the recycling of construction debris an unavoidable operation. Building debris that has been recycled can be utilized as aggregate in the construction of a new reinforced concrete structure. Therefore, the use of construction waste as coarse aggregate should be researched to ensure that the structural behavior of these structures does not differ from that of non-recycled (natural) coarse aggregate buildings (NCA). An experimental investigation was undertaken in this study to explore the influence of recycled coarse aggregate (RCA) on reinforced concrete beams with pure torsion apertures. To research crack pattern, failure mechanism, failure load, torque-rotational angle relation, load-strain relation for longitudinal reinforcement, opening and edge stirrups, and toughness, various RCA ratios are utilized in the construction of RC beams. Six beams with identical cross-sectional dimensions of 150 x 350 mm and a total span of 1400 mm are included in the investigation. The overall beam length was split into three sections, with the center section serving as the test zone and measuring 1000 mm in length. The two cantilevers were 200 mm wide and 350 mm long, and the tested beams included two solid beams and four beams having 300 x 150 mm openings. The RCA replacement ratios of the tested beams were separated into four groups: 0 percent, 30%, 50%, and 100%. At the ages of 7 and 28 days, six cubes are built from each group to investigate compressive strength. The results of the experiments revealed that the existence of an aperture in a beam reduces cracking and ultimate torque. The results of concrete mixes with 30 percent and 50 percent RCA replacement ratios are nearly identical to those of conventional concrete. When compared to concrete mixes with 30 percent, 50 percent, or standard RCA replacement ratios, the concrete mix with a 100 percent RCA replacement ratio yields worse outcomes. The crack patterns for the specimens manufactured with NCA and RCA are identical, according to the tests done on RC beams. However, beams created with 30% and 50% RCA replacement ratios have about the same capacity and durability as NCA-made beams. For beams with a 100 percent RCA replacement ratio, the results are lower يتناول هذا البحث دراسة عملية حول تأثير استخدام ركام كبير مُعاد تدويره في الكمرات الخرسانية ذات الفتحات و المعرضة لعزوم لي ،حيث تم اختبار ست كمرات خرسانية مسلحة ، اثنتان منهما بركام طبيعي إحداهما بدون فتحة و الاخري بفتحة .و الكمرة الثالثة فتم استخدام ركام كبير مُعاد تدويره بنسبة 30% مع وجود فتحة في منتصف الكمرة . و للكمرتين الرابعة و الخامسة فتم استخدام ركام كبير مُعاد تدويره بنسبة 50% و احدي الكمرتين بدون فتحة و الاخري بفتحة. الكمرة السادسة فتم استخدام ركام كبير مُعاد تدويره بنسبة100 % بوجود فتحة أيضا.هدف هذا البحث هودراسة شكل الانهيار وحمل الكسر و العلاقة بين الحمل و الانفعال للحديد و كذلك عزم اللي و زاوية الدوران للكمر المُعاد تدويره.