hey im zack and im reseachin portland cement u think u guys help me i want to find out what is it and how its used? THANKS 4 UR HELP AND TIME
It's the most common form of cement and made from concrete, mortar, stucco and grout. It was developed in England and the result was thought of as being comparable with Portland limestone, an oft used building stone obtained from the south coast in Dorset. Thar's what it's named after.
Steel and Portland cement are what the whole world is made out of ! It is one of the two most important substances known to man. It is very strong in compression (squeezing) but very weak in tension (pulling) so you put steel rebar rods in the concrete. Then you have to best of everything. Portland cement can be mixed to have low or high strength
Portland cement is the most common type of cement in general use around the world, as it is a basic ingredient of concrete, mortar, stucco and most non-specialty grout. It is a fine powder produced by grinding Portland cement clinker (more than 90%), a limited amount of calcium sulfate which controls the set time, and up to 5% minor constituents (as allowed by various standards). As defined by the European Standard EN197.1, Portland cement clinker is a hydraulic material which shall consist of at least two-thirds by mass of calcium silicates (3CaO.SiO2 and 2CaO.SiO2), the remainder consisting of aluminium- and iron-containing clinker phases and other compounds. The ratio of CaO to SiO2 shall not be less than 2.0. The magnesium content (MgO) shall not exceed 5.0% by mass. (The last two requirements were already set out in the German Standard, issued in 1909). Blue Circle Southern Cement works near Berrima, New South Wales, Australia. Portland cement clinker is made by heating, in a kiln, a homogeneous mixture of raw materials to a sintering temperature, which is about 1450 °C for modern cements. The aluminium oxide and iron oxide are present as a flux and contribute little to the strength. For special cements, such as Low Heat (LH) and Sulfate Resistant (SR) types, it is necessary to limit the amount of tricalcium aluminate (3CaO.Al2O3) formed. The major raw material for the clinker-making is usually limestone (CaCO3) mixed with a second material containing clay as source of alumino-silicate. Normally, an impure limestone which contains clay or SiO2 is used. The CaCO3 content of these limestones can be as low as 80%. Second raw materials (materials in the rawmix other than limestone) depend on the purity of the limestone. Some of the second raw materials used are: clay, shale, sand, iron ore, bauxite, fly ash and slag. When a cement kiln is fired by coal, the ash of the coal acts as a secondary raw material.
