Gypsum board, also known as drywall or plaster board, consists of a core of gypsum surrounded with a paper covering. Several varieties of gypsum board products are available; each is comprised of a specially formulated gypsum plaster mix and facing paper specifically developed for the intended application. These gypsum board products include regular gypsum wallboard, moisture resistant gypsum board, and type X fire resistant gypsum board. Gypsum plaster boards are classified according to their use. Gypsum wall board has a face to which decoration may be applied. There are five types of gypsum board product that are considered standard. Innovation has created several new products now available. • Standard Gypsum Board: Regular core, Flexible board, Type “X†fire resistant, Moisture resistant and Plaster baseboard. • Specialty Gypsum Board: Interior ceiling board, Mold & Moisture resistant, Shaft liner, Abuse resistant and Impact resistant. The compressive strength of hardened gypsum plaster boards depends on the quantity of water used in the paste before setting the strength of the product also depends upon its moisture content in the presence of 1% of moisture the compressive strength decreases to about 40% of that of the dry product because of the increased friction between the crystals. Often no further decrease of strength is observed when the moisture content increases over 1%. The bending strength of Gypsum plaster boards is usually 50% of the compressive strength. Gypsum boards and their related products can be used in a variety of applications. Gypsum board is widely used for internal walls and ceilings by the construction industry, and is a material of growing importance in the do it yourself sector. Gypsum board is also a common fire barrier used in house and general building construction. Commonly gypsum boards used in walls and ceilings, in moist areas, in exterior applications, for fire resistance and area separation and special systems. Gypsum plaster board (GPB) popularly known as gypboard, is a low cost, light weight construction material made from aerated gypsum plaster and produced in varying thicknesses suitable for different applications. Gypsum is an important raw material used in the manufacture of cement. Consumption of gypsum varies from 2 to 6% in different plants depending upon the quality of clinker. India has good reserves of natural gypsum, mainly concentrated in Rajasthan, Gujarat and Tamil Nadu. Besides, a number of chemical industries obtain gypsum as a by product in the form of phospho gypsum. The chemical gypsum can be utilised as a whole or as part substitute to natural gypsum. Many cement plants, which are located near the source of phosphogypsum are using this substitute product.
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