Akademik Veri Yönetim Sistemi
2nd International Conference on Civil, Structural and Transportation Engineering (ICCSTE'16), Ottawa, Kanada, 5 - 06 Mayıs 2016, ss.1-7
Many studies are conducted on recycled aggregates. Besides, the use of
fiber in concrete is getting more and more widespread. Recycling of
fiber-reinforced concrete is important for the environment. This study deals
with the recycling of polypropylene fiber-reinforced concrete. The objective of
the study is to use recycled aggregates obtained from polypropylene
fiber-reinforced concrete in new concrete applications. Since a large portion
of the volume of concrete is composed of aggregates, first the aggregate
characteristics were investigated. Eight types of fibers were used in the
study. Each type of fiber was added into concrete mixtures at three different
ratios. The fiber ratios were 600 g/m3, 1200 g/m3 and 1800
g/m3. So, 25 concrete mixtures were produced along with the mixture
without fiber. All mixtures had the same water-cement ratio. Specimens had a
diameter of 150 mm and a height of 300 mm. Their compressive strength ranged
from 33.70 MPa to 45.17 MPa. Polypropylene fiber generally reduced the
compressive strength of concrete. Specimens were crushed using a jaw crusher at
the end of 120 days. From the crushing process, fiber-containing recycled
aggregates were obtained with sizes of 0-4 mm, 7-15 mm and 16-22.4 mm. The
sizes of pieces obtained from the crushing process declined as the amount of
fiber increased. Fibers served as a bonding material, preventing the cement
slurry from being scattered. Particularly, ribbed and hooked fibers were
observed to have provided a better adherence with the cement slurry. Water
absorption, freezing/thawing and impact strength properties of the aggregates
were examined. The properties of aggregates used in the concrete mixture and of
fiber-containing recycled aggregates were compared. Water absorption rate of
fine aggregates ranged from 4.19% to 6.01%. As the size of fiber-containing
recycled aggregates increased, their water absorption capacity increased as
well. Weight losses after freezing and thawing varied between 7.1% and 8.2%.
Weight losses after freezing and thawing increased. Impact strength of
fiber-containing aggregates was approximately twice that of normal aggregates.