نوع مقاله : مقاله پژوهشی
گروه مهندسی عمران، دانشگاه آزاد اسلامی واحد تهران غرب، تهران، ایران
عنوان مقاله [English]
The reusing of recycled aggregates produced from waste concrete is a sustainable solution to reduce the shortage of natural resources. This paper presents the effects of the addition of Nano silica and polyvinyl alcohol (PVA) fiber on the mechanical and microstructural properties of recycled aggregate concrete containing coarse and fine recycled aggregates. Recycled aggregate concrete was produced by 50% and 100% volume substitution of natural fine and coarse aggregate with recycled aggregate. In total, 21 series of concretes are evaluated. The Nano silica in weight ratios of 0%, 2%, 4%, and 6%, and the polyvinyl alcohol fibers in volume fraction of 0%, 0.5%, and 1% were used. The compressive strength, tensile strength, and flexural strength at the different ages of 7, 28, and 90 days are measured in this research. Also, the microstructure of the recycled aggregate concrete was studied via scanning electron microscopy on the selected mixtures.
Test results show that the addition of Nano-silica and polyvinyl alcohol fiber can improve the mechanical and microstructural properties of the recycled aggregate concretes. Also, it was seen that polyvinyl alcohol fiber improves the post-peak behavior of specimens. Moreover, high ratios of Nano silica and PVA fiber in the concrete mixture caused negative effects on the compressive strength of recycled aggregate concrete.