الفهرس 
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Abstract
Concrete is one of the most used construction materials, many researchers showed
interest in developing concrete by replacing concrete components with waste materials to get
rid of these wastes, reduce its production cost, and improve the mechanical properties of
concrete. Accordingly, this study aims to experimentally study the effect of using porcelain
waste aggregate (PWA) and recycled steel fibers (RSF) extracted from scrap tires (SCT) in
concrete. An experimental program was conducted, consisting of two stages. In the first stage,
the concrete mixes were prepared with the coarse aggregate (CA) replaced by (PWA) with
replacement levels of 25%, 50%, 75%, and 100%. Ninety samples were poured, cured, and
tested for fresh and hardened concrete tests to investigate the effect of (PWA) on the
mechanical properties of concrete. Compressive strength was evaluated by the standard cube
test at the ages of 7 days, 28 days, and 56 days. Tensile strength tests were performed on
standard cylinders at the ages of 7 days and 28 days. Flexure strength was measured using a
standard prism (100 x 100 x 500 mm) subjected to bending load at the age of 28 days. In the
second stage, the same laboratory tests were performed for concrete containing 100%
replacement of (PWA) in addition to silica fume (SF) and reinforcement with (RSF) extracted
from scrap tires. Samples of concrete with constant replacement of (CA) by (PWA) by a value
of 100% were also tested to study the effect of (RSF) inclusion to the concrete mix with
percentages of 0.75% and 1.5% and (SF) by 8% and 15%. The extent of improvement in the
mechanical properties of concrete such as compressive strength, tensile strength, and flexure
strength was measured.Test results showed slight decrease in the compressive and tensile strengths of
concrete with the rate of replacement increase of the (CA) by (PWA). However, the flexural
strength of concrete at the age of 28 days showed an increase by 40%, 24%, and 9% for (CA)
replacement by (PWA) by percentages of 25%, 50%, and 75% respectively at the age of 28
days. The mechanical behavior of the concrete has been improved by the addition of (SF) and
(RSF). The mechanical properties of concrete increased significantly as more (RSF) was
added to the mixture, and they increased even more with the addition of (SF).