Impact loads due to ship collision on irrigation structures is significantly decreasing their durability. Loss of material and degradation are quite common problems facing lock walls and piers. In the current research, rubberized self-compacting concrete (SCC) was used to investigate problems associated with impact. SCC with cement kiln dust cement replacement was used for that purpose. Concrete specimens were prepared with different crumb rubber ratios of 10% (RSCC-10), 20% (RSCC-20), 30% (RSCC-30), and 40% (RSCC-40) sand replacement by volume. Standard compressive, flexure, and splitting strength tests were conducted to monitor the effect of the added rubber on concrete behavior. Moreover, impact testing program was applied to specific specimens, cylinder of diameter 200 mm and thickness 50 mm, according to ACI committee 544 procedures. The number of blows to first and ultimate cracks was determined. The relationship between the mechanical properties and impact resilience is also presented. With the increase in rubber percentage the resistance to impact increased, but there was a decrease in specimen strength and modulus of elasticity. The variation in results was discussed and mix RSCC-30 exhibited the best impact resistance, 3 times over control mix with 40% reduction of compressive strength.

Please cite this article in press as: Khalil, E.A.B., Anwar, M., Carbonation of ternary cementitious concrete systems containing fly ash and silica fume. Water Sci. (2015), http://dx. AbstractCarbonation is quite a complex physical negative effect phenomenon on concrete especially in the ones containing ternary blends of Portland Cement, fly ash, and silica fume. Nine selected concrete mixtures were prepared with various water to cementitious materials' ratios and various cementitious contents. The concrete mixtures were adapted in such a way to have the same workability and air content. The fresh concrete properties were kept near identical in slump, air content, and unit weight. The variation was in the hardened concrete mechanical properties of compression and tension strength. The carbonation phenomenon was studied for these mixes showing at which mixes of ternary cementitious content heavy carbonation attacks maybe produced. The main components of such mixes that do affect the carbonation process with time were presented.

The old irrigation hydraulic structures along the Nile and its main branches face the problems of operation, aging, ill maintenance and the desire to extend its lifetime. Economically, building a new one is not feasible. Furthermore, the operation of the irrigation system changed dramatically after building the High Aswan Dam and new design codes replaced the old design methods. Upgrading and enhancing old masonry hydraulic structures in Egypt is an extreme necessity and traditional solutions are not compatible with the operational requirements. For a reason or another, several structures such as Assuit and Zefta barrages have been remodeled. Upgrading and renovating constitute several studies and structural solutions that are not commonly available and has to be taken as a case by case matter, and the literature does not support such cases well. This paper presents several upgrading solutions for an old regulator, where not all methods are convenient. A study of the different methods is presented and analyzed.

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Several existing reinforced concrete structures (RC) require improvement in performance for reasons of deterioration. This is due to many factors such as the change in code requirements. The current study was assisted by experimental models to investigate the behavior of RC slabs strengthened with carbon fiber reinforced polymer (CFRP) laminates and sheets. Seven RC slabs strengthened with CFRP (laminates and sheets) were tested. The slabs were divided into four groups. The first phase includes one slab without strengthening (reference slab), the second phase includes one slab strengthened with CFRP laminates, and the third phase includes one slab strengthened with CFRP sheets. The fourth phase includes four slabs strengthened with different areas of sheets. The major test parameters included the different types of strengthening materials and the corresponding types of epoxies used for each type of CFRP. A comparison between the two types of CFRP was conducted. The load deflection, load strain and mode of failure were investigated. Test results demonstrated that the flexural strength increased, and the ductility reduced with the increase in the area of CFRP sheets. for almost equivalent applied area, CFRP Sheets has more significant influence on the behavior of the strengthened slabs than laminates. Strengthening of RC slabs with CFRP improves the flexural strength capacity for both types. For the same CFRP strength, the sheets showed a cost reduction of 70%. The difference is attributed to the difference in the mechanical properties and the bonding quality of the CFRP material