Advantages And Disadvantages Of Plane And Or Reinforced Concrete

CHAPTER ONE: Introduction

1.1 General:

Plane and/or reinforced concrete consider one of the most important available technique and materials for construction in Egypt and all over the world. It is used in almost all structures as: buildings, shells, bridges, tunnels, tanks and retaining walls. Concrete is made by mixing binding materials as sand and gravel held together with a paste of cement and water. The use of admixture is to change certain characteristics of concrete such as workability, durability and time of hardening. Concrete has many advantages, such as high compressive strength, ability to cast in almost any desired shape, economical and fire resistance. Yet, there are some disadvantages, like low tensile strength, low ductility and cracking. Regardless those disadvantages, concrete is still one of the chosen materials in construction.

Reinforced concrete (RC) is a very complex composite material resulting from a combination of two materials, concrete and steel, both of which have entirely different mechanical properties. Steel can be considered a homogeneous material and its tensile strength and ductility are very high. Concrete is, on the other hand, non-homogenous material made up of different materials as cement, mortar and aggregates. The evaluation of

The material is now being used in an increasing number of applications, ranging from one step house casting to low density voids fills. Foamed concrete has a surprisingly long history and was first used in 1923. Although there is evidence that the Romans used air entrains to decrease density, this was not really a true foamed concrete. Significant achievement 's over the past 20 years in production equipment and better quality surfactants (foaming agents) have enabled the use of foamed concrete on a larger