Concrete Literature Review

Chapter 2

Literature Review

General

Concrete is an important material that can be used in construction. Romans was the first to develope what is known by today as the hydraulic cement-based concrete. Designed some concrete structures, such as the Pantheon in The Rome, one of the best of the Roman architecture that survives to nowadays, the name concrete comes from the Latin "concretus", which means to grow together it is a good name for this material, as the chemical hydration process, which mainly occurs over the time scale of hours and days, causes the material to grow together from a viscoelastic, moldable liquid into a hard rigid solid. Cement is known as the powder that reacts with water to form cement paste, a hard, solid

It has been used for handling any problems or holes in the structure. lately, as it has improved, perceptible has been developed as an employment in other situations.

Portland Cement Figure 1 Portland, England

Portland cement is one of the types of hydraulic cement made by the mixing of a clay and a limestone after burning both of them in a klin.

Portland cement occurrence by Joseph Aapdin was in the 19th century, he named it Portland cement because it produced a concrete that resemble the color with the organic limestone quarried on the Isle of Portland, a peninsula in the English Channel. Since that time, the name has been known as "Portland cement" , and is written in all lower case because it is nowadays recognized as a trade name for a type of material. and AASHTO and ASTM M 85 has designated (8) basic types of Portland cement concrete. Check (Table 1) .

Table 1

Type Name Purpose

I Normal General-purpose cement suitable for most purposes.

IA Normal-Air Entraining An air-entraining modification of Type I.

II Moderate Sulfate

Pozzolans

Pozzolan is a material tha has cementitious properties ratio and a finely-divided material that react with alkalis and calcium hydroxide to make a compound possessing cementations properties. It can be divided into two main categories which are artificial and natural Pozzolans. Natural pozzolans are the type of pozzolans that presents on earth's surface such as diatomaceous earth, volcanic ash, opaline shale, pumicite. These materials must have further processing such as calcining, grinding, drying, etc.

The natural pozzolans has been used in bridges, dams to decrease the hydration’s heat and increase resistance of concrete to sulfate attack and control the alkali-silica reaction.