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Increased productivity and improved working environment have had high priority in the development of concrete construction over the last decade. The major impact of the introduction of self-compacting concrete (SCC) is connected to the production process. The productivity is drastically improved through the elimination of vibration compaction and process reorganization. The working environment is significantly enhanced through avoidance of vibration induced damages, reduced noise and improved safety. Additionally, SCC technology has improved the performance in terms of hardened concrete properties like surface quality, strength and durability. The main objective of this research was to determine the optimum content of fibers (steel and polypropylene fibers) used in SCC. The effect of different fibers on the fresh and hardened properties was studied. An experimental investigation on the mechanical properties, including compressive strength, flexural strength and impact strength of fiber reinforced self-compacting concrete was performed. The results of the investigation showed that: the optimum dosage of steel and polypropylene fiber was 0.75% and 1.0% of the cement content, respectively. The impact performance was also improved due to the use of fibers. The control mix specimen failed suddenly in flexure and impact, the counterpart specimens contain fibers failed in a ductile manner, and failure was accompanied by several cracks.

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Nano ferrite/cement composites (NFCC) have been prepared by adding different weight ratios of Nano ferrite (N.F) ranging from (1 up to 4%) cement. This study is aimed to evaluate the effect of addition of N.F on the mechanical behavior of NFCC and study the performance of cement pastes and cement mortars mixed with Nano ferrite (N.F) when exposed to elevated temperatures of 200 oC and 400 oC, for firing period of two hours. Compressive strength test showed valuable enhancement in mechanical properties of NFCC with increasing N.F loading ratio. The obtained minerals of Cu-Zn ferrites nanoparticles were identified by using X-ray diffraction (XRD) and the morphology of N.F was determined using transmission electron microscopy (TEM). The microstructure of the NFCC was characterized by means of scanning electron microscope (SEM) analysis. The addition of N.F by about 1% enhanced the compression strength to about 52 % for cement paste and1% enhanced the compression strength to about 35% for cement mortar. The results indicated that cement pastes and cement mortars mixedwith N.F are more able to resist elevated temperature than pure cement pastes.

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