Two-stage concrete (TSC) is a special type of concrete that themethod of its construction and implementation is different fromconventional one. In TSC, coarse aggregate particles are first placed in the formwork and voids between themare subsequently injected with a special cementations mixture. TSC has been successfully used in many applications, such as underwater construction, casting concrete sections congested with reinforcement and concrete repair. Coarse aggregate forms about 60% of the total volume of TSC, while coarse aggregate forms about 40% of the total volume of conventional concrete. In TSC stresses are transferred through contact areas between coarse aggregate particles. In this paper coarse aggregate size influence on strength parameters of TSC and comparing it with conventional concrete is done (by uniaxial compressive strength test and Brazilian tensile strength test). According to results of tests in this paper, the TSC with finest grain of coarse aggregate has higher compressive and tensile strength, higher modulus of elasticity and less Poisson’s ratio from conventional concrete. arabic 11 English 66
Hakim Salem Abdelgader Abdelgader (3-2019)

This report includes a short history on the early development of conveyor belts for transporting and placing concrete; the design of conveyor systems in relation to the properties of the plastic concrete, the delivery rate, and the job specifications; as well as belt widths, speeds, and angles of inclination as they apply to specific site requirements. Also discussed are the three types of concrete conveyors (portable, feeder, and spreader types) and their particular applications; field practices in the selection, use, and maintenance of conveyors; and the economics of belt conveyor placement. The quality of the in-place concrete and inspection procedures are also stressed. arabic 7 English 39
Hakim Salem Abdelgader Abdelgader (4-2020)

Abstract Structural analysis is the mathematical calculation of forces, stresses, and deflections within structures, either as part of the design of those structures or as a tool in understanding the performance of existing structures. There are two broad classes of analysis: classical methods and matrix methods. The distinction is based on theory: classical methods were developed to analyze particular types of simple structures and provide answers by means of analytical formulation; matrix methods which are more general and systematic so that they can be conveniently handle structures of any size and complexity, and are computer-oriented using matrix computations. Both approaches, however, are based on the same three fundamental relations: equilibrium, constitutive, and compatibility. The solutions are approximate when any of these relations are only approximately satisfied. Finite element analysis, which originated as an extension of matrix analysis to surface structures (e.g., plates and shells), has now developed to the extent that it can be applied to structures and solids of practically any shape or form. The application of these methods usually requires an understanding on the part of the analyst of the structural analysis principals. The objective of this thesis is to give comparative study of the methods applied in the structural analysis: Classical, Matrix, and Finite-Element.
مالك أحمد النفاتي (2009)