material of civil engineering: 2012

Mounds of white Portland cement powder

In addition to the two main forms of cement which exist, hydraulic and non-hydraulic, there are also several types of hydraulic cements that can be made and used in construction.
The main form of cement used in construction worldwide today is the hydraulic cement called Portland cement.
Portland cement is a type of hydraulic cement made by heating a limestone and clay mixture in a kiln and pulverizing the materials.

Portland Cement Clinker

It is a fine, grey or white powder that is made by grinding Portland cement clinker, a limited amount of calcium sulfate which controls the set time, with other minor constituents.
Portland cement is the most common type of cement in general usage in many parts of the world.
The cement is used as the basic ingredient of concrete, mortar, stucco and most non specialty grout. All references to cement worldwide refer to Portland cement, as it constitutes virtually all cement produced

Portland cement concretes made by mixing portland cement

Manufacture of Ordinary Portland Cement

Hydraulic cements are cements that have the ability to set and harden after being combined with water.
As a result of chemical reactions, after hardening hydraulic cement mixtures retain strength and stability even when in contact with water.
Due to the fact that hydrates that are formed when hydraulic cement is initially in contact with water the new mixture becomes essentially insoluble in water. That gives hydraulic cement a strength and stability that makes it distinct from non-hydraulic cement.

Slag cement is a white-coloredhydraulic cement that will lighten the color

Hydraulic cement is made primarily from limestone, certain clay minerals, and gypsum, which are burned together in a high temperature process that drives off carbon dioxide and chemically combines the primary ingredients into new compounds.

Hydraulic cement mix. Water and a robust water container

Setting and hardening of hydraulic cements is caused by the formation of water-containing compounds, which are formed during reactions between cement components and initial contact with water.
The compressive strength of the material grows steadily over a period that can range from a few days in the case of ultra-rapid-hardening cements to several years in the case of primitive hydraulic cements.
The ability to withstand continuous contact with water, in addition to the ability to set and harden quickly, and greater relative strength makes hydraulic cement the main cement utilized in modern day construction.

Instant water

Basement waterproofing

Non-hydraulic cement is more basic and was the first form of cement invented by early scientists.
Non-hydraulic cement is cement which cannot harden while in contact with water.
Non-hydraulic cements are created using materials such as non-hydraulic lime and gypsum plasters and oxychloride, which has liquid properties.

Non-Hydraulic lime

After non-hydraulic cement is utilized in construction, it must be kept dry in order to gain strength and hold the structure.
When non-hydraulic cement is used in mortars, those mortars can set only by drying out, and therefore gain strength very slowly.
Due to the difficulties associated with waiting long periods for setting and drying, non-hydraulic cement is rarely utilized in modern times.

Lime mortars (non-hydraulic) are flexible and soft.

For building purposes, high calcium, non-hydraulic quicklime can be used .

Cement is a binder, a substance that sets and hardens independently, and can bind other materials together.
Any of various calcined mixtures of clay and limestone,usually mixed with water and sand, grave etc., to form concrete, that are used as a building material.
Any of various soft, sticky substances that dry hard orstonelike, used especially for mending broken objects or formaking things adhere.

It can be either a small towable device used to mix cement

Cement powder

Monday 27 February 2012