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The construction industry is considered one of the most important industries in Egypt. The majority of construction projects are known to have time delays and cost overruns. The main contribution of this study is that it is the first study of its type that identifies causes of delay and cost overrun in educational building projects with its different types (public schools, private schools, public universities, and private universities) within Egypt. The research main objective is to identify the causes of delay and cost overrun in educational building projects in Egypt and evaluate their importance by the main project stakeholders (Consultants, Contractors, and Owners). This objective was accomplished by means of an extensive literature review and a questionnaire-

Repairing of reinforced concrete beams by using thin fibers concrete jacket have many advantages such as increasing of ultimate load, enhancement of serviceability limit state, resistance to fire and avoiding of corrosion problems that appear in steel plate jacket. This paper reports investigations conducted to study the repairing of reinforced concrete beams subjected to short time repeated loading by using mixed steel fibers concrete jacket (MSFCJ). For this purpose, eight reinforced concrete beams have 120×300×2300 mm dimensions were fabricated and tested under three point load. The used concrete mix contains two mixed shape of steel fibers, corrugated and endhooked steel fibers. Two of these beams were fabricated without jacket, the first was tested under static load up to failure and the second was tested under short time repeated loads up to failure. The rest six beams were loaded up to 0.5 the ultimate static load and then repaired by U-shape jacket (MSFCJ) with various thickness and steel fibers content. The test results showed the effectiveness of the proposed technique in the behavior of such beams.

Mn-Ferrite nanoparticles were prepared using citrate auto combustion method. The prepared sample was characterized by X-ray diffraction (XRD), HRTEM and BET to measure the particle diameter and the surface area of the prepared sample. The data of XRD clarified that the sample was formed in single phase spinel structure without any extra peaks indicating non-existence of any secondary phase. The HRTEM micrograph indicated that the particles were in an agglomerated state due to the absence of surfactant and high magnetic properties of Mn-Ferrite nanoparticles. The mechanical properties were measured at different ratios of nano-Ferrite to concrete. The obtained values of mercury intrusion porosimetry (MIP) indicated that the addition of Mn-Ferrite nanoparticles increased the compressive strength and decreased the total intrusion volume. This was due to the rapid consuming of Ca(OH)2 which was formed during hydration of Portland cement especially at early ages due to the high reactivity of MnFe 2 O 4 nanoparticles. Moreover, MnFe 2 O 4 nanoparticles recovered the particle packing density of the blended cement, leading to a reduced volume of pores in the cement paste.