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The aim goal of this research was to study the effect of using the waste-iron which product from milling processes on the mechanical properties of concrete. The tests performed to evaluate waste-iron concrete are compressive strength, splitting tensile strength and flexural strength tests. Sixty cubes of concrete for the compressive strength, sixty cylinders of concrete for the tensile strength, and Sixty prisms of concrete for the flexural strength tests with different volume fractions of waste-iron (1%, 2%, 3% and 4%) were prepared. The specimens were tested at 7, 14 and 28 days age. The results show that the concrete mixes with waste-iron have a higher compressive strength, tensile strength and flexural strength than the plain concrete mixes. Concrete containing volume fractions 3% ratio of waste-iron has the maximum value of compressive strength, tensile strength and flexural strength. The primary effect for adding the waste-iron to the concrete is to improve the post-cracking behavior.
الهدف من هذا البحث هو دراسة تأثير اضافة برادة الحديد الناتجة من عملية التفريز الى الخرسانة ودراسة تأثيرها على الخواص الميكانيكية للخرسانة ، لقد تمت دراسة مقاومة الإنضغاط ومقاومة الشد ومقاومة الإنثناء. في هذه الدراسة تم صب 60 مكعب لفحص مقاومة الإنضغاط و60 أسطوانة لفحص مقاومة الشد و60 موشور لفحص مقاومة الإنثناء بنسب حجمية مختلفة من برادة الحديد (1%، 2%، 3%، 4%) ، هذه الفحوصات تمت بأعمار مختلفة للخرسانة 7 و 14 و 28 يوم. أظهرت النتائج بأن الخلطات الحاوية على برادة الحديد لها مقاومة أنضغاط ومقاومة شد انشطاري ومقاومة أنثناء أعلى في الخلطات الحاوية على برادة الحديد. الخرسانة الحاوية على برادة الحديد بنسبة 3% أعطت اعلى زيادة في مقاومة الإنضغاط ومقاومة الشد ومقاومة الإنثناء. والتأثير الأكبر لبرادة الحديد هي زيادة مقاومة التشقق للخرسانة.
plain concrete --- waste-iron --- Slump test --- compressive strength --- tensile strength and flexural strength.
Polyvinyl alcohol (PVA) has undergone intensive research work that has led to confidence in its utilization in various applications. Nevertheless, its utilization as a construction material in the concrete industry still needs to be fully addressed. In this paper, an experimental study was dedicated to investigate the influence of PVA on the fresh and hardened properties of concrete. Three different strength grades, represented by water to cement ratios (w/c), of 0.4, 0.5 and 0.6, with four different PVA dosages of 1, 2, 3 and 4%, by mass of cement, were employed in the preparation of the concrete mixes. Concerning the fresh properties, results showed that there was a significant contribution of PVA to the workability in all produced mixes, irrespective of w/c ratio. In addition, the initial and final setting time of cement pastes modified with 2% PVA were longer than that of the control paste. In term of the hardened properties, results demonstrated that the compressive (fcu) and splitting tensile (fst) strengths of concrete are dominated by amounts of PVA in the mix and w/c ratios. With the high and moderate w/c ratios, they increased when up to 2% PVA was used, and thereafter decreased. However, with the low w/c, PVA did not provide any improvement in the strength, but instead, it decreased the strength when more than 2% was added. The findings revealed also that increasing PVA content resulted in a significant reduction in total water absorption (TWA) of concrete specimens. The larger the PVA contents the lower is the TWA of the specimens
polyvinyl alcohol --- compressive strength --- tensile strength --- slump test --- total water absorption
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