الفهرس 
chapter 1Only 14 pages are availabe for public view
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Abstract
Concrete wastes are generally delivered to the landfill sites for disposal. Due to
increasing charges of landfill and scarcity of Natural Coarse Aggregate (NCA),
Recycled Concrete Aggregate (RCA) derived from concrete wastes is growing
interest in construction industry.
In the present study, RCA was used as partial and full replacements of NCA to
produce Self Compacting Concrete (SCC) without and with using marble
powder substituting 10% , 20% , 30% and 40% was studied . Also ,the effect of
high range water reducing admixture (sikament-NN) was studied.
In this research SCC mixes were divided into five group produced with RCA
substituting 0%, 25%, 50%, 75%, and 100% NCA by weight with 3%
admixture. The first group without marble powder (MP) and the other group
with MP varies from 10% to 40% .The water to powder (W/P) ratio are variable
after adding water absorption to concrete mixes.
The effects of RCA on the key fresh properties such as filling ability, passing
ability, and segregation resistance of SCC were investigated. The test results
revealed that the filling ability and passing ability of SCC were improved for all
mixes. All mixes of SCC has adequate segregation resistance. In addition, strong
correlations were observed for passing ability, and segregation resistance.
The compressive and splitting tensile strength are decreased by increasing RCA
percentages. However the compressive and splitting strengths are increased by
using 10% MP with different RCA replacement .
Abrasion resistance , Cantabro test and RCPT test to evaluate durability are
improved by using 10% MP.
from the overall test results it could be concluded that RCA can be used to
produce SCC substituting up to 75% NCA without affecting the key properties
of fresh concrete. All mixes contain 0% and 10% MP gives strength greater than
normal concrete strength and improve durability with various RCA percentages
with using 10% MP.