Guide To Learn
Prior to 1987, theDIFFERENT GRADES OF CEMENT Prior to 1987, there was only one grade of Ordinary Portland Cement which was governed by IS 269-1976. After 1987 higher-grade cements were introduced to India. The Ordinary Portland Cement was classified into three grades, namely 33 grade, 43 grade and 53 grade depending upon the strength of […]
4.4.1 Wet process In the earlier part of the century, from 1913 to 1960, the wet process was used for the manufacture of cement. 4.4.1.1 Mixing of raw materials The calcareous materials such as limestones are crushed and stored in silos or storage tanks. The argillaceous materials, such as clay, are thoroughly mixed with water […]
When water is added to cement, the ingredients of cement react chemically with water and form a complicated chemical compound. The mixing of cement with water results in a sticky cement paste and it gradually goes on thickening in course of time. It is found that ordinary cement achieves 70 per cent of its final […]
4.2.1 Harmful constituents of cement The presence of alkali oxides like K2O and Na2O and magnesium oxides like MgO adversely affects the quality of cement. If the amount of alkali oxides exceeds 1 per cent, it leads to the failure of concrete. If the content of magnesium oxide exceeds 5 per cent, it causes cracks […]
The properties of cement are:
Lime can be used for the following purposes:
The process of mixing water in quick lime is known as slaking of lime. It is an important operation in the preparation of lime at site for use in building construction. Improper slaking results in serious defects in mortars and plasters. Figure 3.3 Continuous flare kiln Two methods are commonly used for slaking […]
3.3.1 Calcination Lime is manufactured by the burning of limestone to bright red in suitable kilns or clamps. Theoretically, limestone dissociates when heated at 880°C into carbon dioxide and calcium oxide, which is also reversible. CaCO3 ↔ CaO + CaO2 The burning or calcination of limestone can be carried out in one of the following ways: […]