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for columns around 36hours, slabs 7days up to 4.5m spans, and beams 14 days depending on the span
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What is the time period for expiry of ordinary portland cement?
cement experiy time
How gypsum effect the setting time of cement?
gypsum increase the setting time of cement.
Who are the retarders for concrete?
Retarders are classified as type B or type D chemical admixtures for portland cement concrete in ASTM Designation C494. Their primary function is, as the name implies, to retard the setting time of concrete.
What is the importance of setting time of cement?
because when we know the setting time of cement we easily identified that where can we use the cement according to there setting time.
What are the factors affecting the initial setting time of cement?
When cement is mixed with water, it forms slurry which gradually becomes less plastic with the passage of time & finally a hard mass is obtained. In this process, at a certain stage when the cement paste is sufficiently rigid to withstand a definite amount of Pressure, it is said to have set & the time required to reach this stage is termed as "setting time".
What is the time period for expiry of ordinary portland cement?
cement experiy time
Difference between ordinary Portland cement and puzzalona Portland cement?
OPC - Ordinary Portland cementOPC - Materials used - Argillaceous and calcareous materialsPPC - Portland Pozzolona CementPPC - OPC + Pozzolonoc materials(fly ash, volcanic ash, pumicite at the time of grinding).
Who discovered cement?
ruldoph aspdin Perhaps Joseph Aspden 1824, who named his cement 'Portland Cement' after the appearance of a recognized quality building stone of the time. This is effectively our modern Cement.
How can you make portland cement as quick setting and water resistance cement?
Please note that a key correction in terminology is essential before your question can be answered: use the word "concrete" instead of "cement." The answer is to modify your mix (i.e. Portland cement, sand, gravel, and water) by using hydraulic cement to repace part of the Portland cement. The higher the amount of hydraulic cement you add, the quicker the setting time and the impermeability. However, hydraulic cement sets so quickly that you have limit the amount of total mix so as to be able to pour it and form it before it sets.
What is the difference between portland cement and pozzolan cement?
There are three kinds of cement PPC, OPC. SRC. Portland Pozzolana Cement (PPC) The Portland Pozzolana Cement is a kind of Blended Cement which is produced by either intergrinding of OPC clinker along with gypsum and pozzolanic materials in certain proportions or grinding the OPC clinker, gypsum and Pozzolanic materials separately and thoroughly blending them in certain proportions. Pozzolana is a natural or artificial material containing silica in a reactive form. It may be further discussed as siliceous or siliceous and aluminous material which in itself possesses little, or no cementitious properties but will in finely divided form and in the presence of moisture, chemically react with calcium hydroxide at ordinary temperature to form compounds possessing cementitious properties. It is essential that pozzolana be in a finely divided state as it is only then that silica can combine with calcium hydroxide (liberated by the hydrating Portland Cement) in the presence of water to form stable calcium silicates which have cementitious properties. The pozzolanic materials commonly used are: Volcanic ash Calcined clay Fly ash lica fumes OPC is environment friendly as well as economical Ordinary Portland Cement (OPC-53, OPC-43, OPC-33) OPC-43 GRADE The 43 grade OPC is the most popular general-purpose cement in the country today. The production of 43 grade OPC is nearly 50% of the total production of cement in the country. The 43 grade OPC can be used for following applications: General Civil Engineering construction work RCC works(preferably where grade of concrete is up to M-30) Pre-cast items such as blocks, tiles, pipes etc Asbestos products such as sheets and pipes Non-structural works such as plastering, flooring etc. The compressive strength of cement when tested as per IS code shall be minimum 43 MPa. The physical and chemical properties of this cement are given in the table: Physical Characteristics of 43 Grade OPC (BIS Requirement) Is Code Finene SS (sq.m/k g Min) Soundness by Setting Time Compressive Strength Lechatlier (mm)max Auto clave Max (%) Initial (mts) min Final (mts) Max 1 day Min Mpa 3 day Min Mpa 7 day Min Mpa 28 day Min Mpa (IS 8112- 1989) 225 10 0.8 30 600 Not specified 23 33 43 Chemical Characteristics of 43 Grade OPC (BIS Requirement) Is Code Lime Saturation Factor Alumina Ration Min Insoluble MgO (%) Sulphuric Anhydride Loss ignition (%) Max (IS 8112 - 1989) 0.66 Min 1.02 Max 0.66 3 6 2.5% Max when C3A is 5 or less. 3% Max when C3A is greater than 5 5 Sulphate Resisting Portland Cement (SRC) Sulphate Resisting Portland Cement is a type of Portland Cement in which the amount of tricalcium aluminate (C3A) is restricted to lower than 5 % and (2 C3A + C4AF) lower than 25%. The SRC can be used for structural concrete wherever OPC or PPC or Slag Cement is usable under normal conditions.
What are the characteristics of ordinary Portland cement?
Ordinary Portland cement (OPC) is by far the most important type of cement.The OPC was classified into three grades, namely 33 grade, 43 grade and53 grade.High heat of hydrationInitial setting time is 10 minsFinal setting time is 10 hrs.It is used in construction of buildings, bridges, hydraulic structures,etc.,
Can any body help us with the manufacture of cement copper?
Portland cement is the most common type of cement in general usage in many parts of the world . It is a basic ingredient of concrete, mortar, stucco and most non speciality grout. It is a fine powder produced by grinding portland cement clincer ,alimited amount of calcium sulphate which controls the set time and upto 5% minor constituents. the aluminum oxide and iron oxidearepresent as a flux and contribute little to the strength.
If you are traveling from Portland to Oklahoma City and you arrive in Oklahoma City at 5PM local time. What time is it in Portland?
3PM in Portland.
Can you cook rocks?
Rocks are cooked all the time. It's how humankind derives many useful products from something as simple looking as a rock. Portland cement is, in part, derived from cooking limestone, for instance.
9 pm eastern time is what time in Portland?
Portland Maine is also on Eastern time. Portland Oregon is on Pacific time: 6 pm
How gypsum effect the setting time of cement?
gypsum increase the setting time of cement.
Who are the retarders for concrete?
Retarders are classified as type B or type D chemical admixtures for portland cement concrete in ASTM Designation C494. Their primary function is, as the name implies, to retard the setting time of concrete.
