الفهرس 
الغلافOnly 14 pages are availabe for public view
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Abstract
The main problem of concrete is how to increase its strength without affecting its durability, so the strength and durability of concrete need to increase. There are many ways to improve concrete overall properties, and its durability one of these ways is a new technique using carbon nanotubes to improve concrete characteristics. Carbon nanotubes are very small materials in comparison with .concrete component scale, but this very small material has very high chemical, phys.icai and mechanical properties so it has a very good effect on concrete overall characteristics and properties.
This small material works as activator of the hydration of cement that happens in concrete, it goes directly to the concrete matrix and covers the calcium hydro silicate, and it provides the matrix with new formations.
The analysis of a microstructure of cement matrixes in the composite materials that are modified by multilayer carbon nanotubes has shown radical restructurings in the morphology of the crystal hydrates of cement matrix. The Changes on morphology of the matrix lead to (2-3 times) increase of mechanical durability of the mineral compositions modified by midget quantities nanotubes (within 0,003 - 0,006 % of weight of cement). The reason of such radical change in properties of the modified concrete is due to the interface layer in the composite materiall’ocated on the border between the surface of particles of a mineral aggregate and the cement,.matrix.
The introduction of multi layer carbon nanotubes into cement matrix produces a high dispersion of cement into the concrete, this produce a high level of hydration and the dispersion of cement produce a significant increase of bonding bet’Yee11 concrete particles The experimental program consisted of preparing two types of beams samples 40 X 40 X 160 mm and cubes samples 50 X 50 X 50 mm. The beam samples were tested under bending to determine the flexural strength then tested the two particles resulting from this test under compressive load to detem1ine compressive strength of concrete that was modified with multilayer carbon nanotubes in comparison with control samples. Cube samples were tested under compressive force only to detem1ine the compressive strength of concrete.
The multi layers carbon nanotubes which have been used were produced by a French company ”Arkema”. These nanotubes were dispersed in water using different methods. The main method used was ”hydrodynamic cavitations at high speed”. Local materials have been used like Sinai cement and fine aggregate.