الفهرس 
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Abstract
Self-compacting concrete (SCC) is an innovative concrete that does not require vibration for placing and compaction. It is able to flow under its own weight, completely filling formwork and achieving full compaction, even in the presence of congested reinforcement.
The main objective of this research was using the demolitions of buildings which located too much these days as a coarse aggregate in selfcompacting concrete .And also improving the mechanical properties for this type of concrete by adding different types of fibers (polypropylene fibers, glass fibers and steel fibers). Also the optimum volume friction of used fibers was investigated. The parameters of the study used for this purpose were; water per cement ratio was (0.4-0.55), dolomite content ranged (629 -717 kg/m3), sand content ranged (944 – 1076 kg/m3), recycling materials (broken ceramic and broken red brick) with different percentages (25, 50, 75 and 100 %) as a replacement of dolomite, and different types of fibers
(polypropylene fibers, glass fibers and steel fibers). The Polypropylene fibers has aspect ratio (L/D) =12.5 and volume friction varied from (0.0- 0.56%) for broken red brick and for broken ceramic ranged from (0.0- 1.5%). The Glass fibers has different aspect ratio varied from (1920, 800 and 480) and volume friction varied from (0.0-0.4%) for red brick and for broken ceramic ranged (0.0-0.2%). The Steel fibers has aspect ratio (L/D) =65 and volume friction varied from 0.0-1.0% for red brick and for ceramic ranged from 0.0-2.0%. The fly ash content used was 10%, 15%, and 20% as cement content and the BVF1 content were 1.0 %, 2 % and 2.5 % as a filler content. The tests recommended to determine the SCC characterization of fresh concrete were: slump flow test, V-funnel test (Fillingability, Efficiency of using different types of fibers in self-compacting concrete segregation resistance), J-ring test (passingability), the tested recommended for hardened concrete: compressive strength, splitting tensile test, flexure test, and density of concrete. Results from these tests shown that the optimum volume friction for polypropylene fibers was (0.19 % for broken red brick and 0.75 % for break ceramic ) and for glass fibers was (0.05 % for broken red brick and break ceramic ) and for steel fibers was (0.25 % for broken red brick and 1.0 % for break ceramic ). In case of using demolitions of buildings as recycled materials from weight of coarse aggregate, the compressive strength decreased by 19.44 % and 21.38 % respectively .And in case of using 25 % from demolitions of buildings, the compressive strength increased by 26.55 % and 59.01 % for the mixes which containing polypropylene fibers and the compressive strength decreased by 6.89 % for broken red brick and increased by2.47 %for break ceramic for the mixes which containing glass fibers and the compressive strength had the same value with using broken red brick and increased by 11.31 % for break ceramic for the mixes which containing steel fibers .In case of using demolitions of buildings with percentages (50-75-100%) with polypropylene fibers with broken red brick the compressive strength decreased by 22.22 % and 27.77% and 36.11% and with break ceramic the compressive strength increased with percentage (50%) by 5.56% and decreased with percentages (75-100%) by 8.33% and 25.00% respectively. And with glass fibers with broken red brick the compressive strength decreased by 27.5% and 31.11% and 37.5% respectively and with break ceramic the compressive strength decreased by 34.7% and 38.89 % and 41.67% and with steel fibers the compressive strength with broken red brick the compressive strength decreased by 44.44% and 47.22% and 48.61 % respectively and with break ceramic the compressive strength decreased by 24.44% and 25.83 % and 27.78% respectively.