Concrete technology : The branch of Civil Engineering which deals with the fundamental principles of concrete, is known as Concrete Technology.
In this subject We will Learn:
Properties of concrete in plastic state, Properties of concrete in hardedned state, Advantage of concrete, Disadvantage of concrete, Ingredients of concrete,cement aggregate and water,Types of cement,Important properties of various types of cement.,Physical tests of cement,Effect of water cement ratio on the strength of concrete,water cement ratio,workability,factors affecting the workability,methods to determine the workability of concrete,slump test,compaction factor test, Vee-bee Consistometer,Good qualities of an ideal aggregate,classification of aggregate.
Following types of cement are generally used for various types of structures :
- Ordinary Portland cement.
- Luw heat cement
- Rapid hardening foreland cement
- Blast-furnace slag cement
- Sulphate resistant cement
- Air entraining cement
- White and coloured cement.
In addition to above, the following types of cements are also available :
- High alumina cement
- Pozzolana cement
- Oil well cement.
ADVANTAGES AND DISADVANTAGES OF CONCRETE Content of this article: Advantages of concrete,Disadvantages of concrete,advantages and disadvantages of concrete,inert material acts as a filler and the binding materials.Rcc Concrete is considered as a chemically combined mass where the inert material acts as a filler and the binding materials act as a binder. The most important binding materials are cement and lime. Inert materials used in concrete are termed as aggregates. Most common aggregates are sand, brick chips, stone chips, gravels, shells etc. The concrete plays a very important role in all branches of civil engineering. Concrete is an inexpensive, quick and durable way to complete many construction projects. However, there are advantages and disadvantages associated with this material. For example, while concrete becomes stronger and more durable with time, it is susceptible to water and freezing temperatures, meaning that water can seep into cracks and cause damage to the concrete. There…
Contents of this article:properties of concrete in plastic state,properties of concrete in hardened state,concrete in setting state,workability,water cement ratio. Properties of Concrete in Plastic State concrete in Plastic State When the concrete is first mixed it is like bread dough . It is soft and can be worked or moulded into different shapes. In this state concrete is called PLASTIC. Concrete is plastic during placing and compaction. The most important properties of plastic concrete are workability and cohesiveness. Properties of Concrete in Hardened State concrete in Hardened State After concrete has set it begins to gain strength and harden. The properties of hardened concrete are strength and durability. Hardened concrete will have no footprints on it if walked on. concrete in Setting State Concrete then begins to stiffen. The stiffening of concrete, when it is no longer soft, is called SETTING. Setting takes place after compaction…
In this article Learn : Workability of concrete and Compaction factor test. WORKABILITY OF CONCRETE It is the amount of work required to place concrete and to compact it thoroughly. Workability of concrete increases with the addition of water but it reduces the strength and as such it is not a very desirable way of increasing the workability. Use of aggregates which are round and have smooth surfaces increases the workability. Keeping the cement, aggregates ratio the same if the quantity of coarse aggregate is increased then the workability improves. Workability could also be improved by adding Air-entraining agents such as Vinsol resin or Darex etc. Use of Lisapole liquid at the rat of 30 c.c. per bag of cement improves not only the workability but also the water tightness of concrete. Slump test gives an idea of only the flowing property of wet concrete and not of the workability.…
In this article Learn : Water cement ratio and slump test Water cement ratio : It is the ratio of water and cement (by weight or by volume) used in the preparation of concrete. The quantity of water used in mixing concrete is very important. If the percentage of water used is less then there shall not be sufficient quantity of water to hydrate cement. It shall result in porous and weak concrete. However, the usual tendency is to use too much water which gives a more workable mix but it does not give sound concrete. Too much of water results in segregation of aggregates and gives porous concrete of low strength and low density. (Fig. 8.1.). A certain minimum proportion of water is necessary in order to hydrate the cement completely. To make the concrete sufficiently workable to be placed in position some more water is needed. So…
In this article Learn : cement concrete,cement concrete ingredients, selection of material,cement, fine aggregate,coarse aggregate,water,Batching of ingredients by weight and by volume mixing, placing of concrete CEMENT CONCRETE It is a composite material where in a paste of cement, made with water, on solidification binds firmly together the various particles of inert materials like sand and stone ballast. The inert material called "aggregate" is well graded in size from fine sand to pebbles or stone ballast or brick ballast. Cement concrete is an extremely versatile material of construction which is used for a variety of works ranging from small cottages to massive dams and bridges. Cement concrete is quite strong in compression but not so in tension. To make good this deficiency of concrete steel bars (reinforcement) are embedded in concrete. The concrete then is known as reinforced concrete. The four materials go to make cement concrete : (i) Cement…