| Topic : Advances in Cement and Building Materials |
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Construction Planning & Management
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Activity:
Question posted: 12 22 2008 14:30:33 +0000,
15 answers, 6689 views, last activity
07 02 2011 01:47:10 +0000
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Mr Mehernath has rightly briefed.
I start with PPC. Advantage: low cost, environmental friendly, low heat of hydration
Disadvantage: Low early strength (does not attain 100% of its characteristics strength in 28 days, 7days strength is generally 75% of 28 days against 85% in OPC 53gr), not found suitable for high grade concrete.
Suited for: low strength concrete (upto M30), plastering and flooring etc where shrinkage cracks may affect the finished look. Concrete not needing high early strength.
NOTE: IS codes for PPC and concrete with PPC need revision
OPC: As told by Mr Mehernath 33 grade is almost not available. 43 grade and 53 grade are available but 43 grade is also not abundantly available.
53 grade is finer thus more surface area thus higher heat of hydration but higher strength, high early strength. Good for concrete of high to very high strength, in thick structural elements like beams and precast works (because of high early strength). In structures like slab since more area of concrete is exposed to sun and wind thus possibility of cracks are more. But if adequate curing precautions (i.e. start ASAP and keep wet) are taken then cracks can be limited to surface thus causing no practical structural defeciency.
43 grade is relatively coarserer, low heat (but more than PPC), lesser cracks (but not to be taken for granted). Not suitable for very high strengths (M50 and above). If proper care is taken for curing then severity of cracks, if any, will be less than in 53 grade. Not readily available in market as 53 grade (for use in large qtys.).
PPC IS BETTER THAN OPC. PPC gets better lateral strength. It is corrosion resistant, more resistant to chemicals, alkalies when compared to OPC.
PPC is more better as compare to opc.
it is suggested to use ppc cement due to its economical, enviornment friendly, corroision resistant,
and super strength upto 1 year.
and if the W/c ratio and mix ratio of concrete is maniintained during concreting that u will definately get good strength in 28 days....
no doubt its initial setting is slow but due to sow setting it reduces heat of hydration.. which is very good for concrete.
and above i have sepecified that it has super strength it means in ppc ur concrete strenght increases upto 1 year...
and i am not agree with above answers that " ppc cannot be used in heavy grade/ structures or ppc can only be used in dmomestic construction & not in infrastructures" i do not aggree at all....
bcoz in england, A Tunnel was constructed under land and water they have used 100% ppc with 40 to 50 % fly ash added in opc. and they have got very good strength...
ultimately for strength cement plays imp role but workmanship and w/c ratio in concrete too plays very important role...
So, According to me PPC is much more better than OPC.....
We should used only PPC , as production of OPC may come to an end in coming future.
& PPC is also Eco-friendly.
Original Source: [Tips'n'Bits]: Do You Know Which Cement Type To Buy & Use?
http://www.bricks-n-mortar.com/2008/04/tipsnbits-do-you-know-which-cement-type.html
Like Mr. Singh, the majority of masses and classes have no idea to similar queries of the cement vendors (barring the ordinary shopkeepers, who themselves don't know beyond the word- 'CEMENT'). The last resort left with Mr. Singh was to tell the vendor to give him whichever type the vendor felt right. And no doubt, like most of the vendors would have done in such a situation, Mr. Singh was handed over the type of cement bags, which had huge profit margins for the vendor.
Original Source: [Tips'n'Bits]: Do You Know Which Cement Type To Buy & Use?
http://www.bricks-n-mortar.com/2008/04/tipsnbits-do-you-know-which-cement-type.html
Like Mr. Singh, the majority of masses and classes have no idea to similar queries of the cement vendors (barring the ordinary shopkeepers, who themselves don't know beyond the word- 'CEMENT'). The last resort left with Mr. Singh was to tell the vendor to give him whichever type the vendor felt right. And no doubt, like most of the vendors would have done in such a situation, Mr. Singh was handed over the type of cement bags, which had huge profit margins for the vendor.
OPC and PPC are two different types of Cement.
OPC is used for Infrastructure projects
PPC is used domestic constructions i.e small projects like builing house and small constructions.
PPC IS BETTER THAN OPC. PPC gets better lateral strength. It is corrosion resistant, more resistant to chemicals, alkalies when compared to OPC. Better finishing is possible with ppc.
In PPC Fly Ash is used which is available in Thermal power stations. It replaces clinker mahufactured out of limestone ,lataract ,coal etc utilising mines. Utilisation of fly ash (which has cementing properties save energy as well as earth.
According to me, OPC is better than PPC as OPC is without fly ash content and has more compressive strength.Since gradation of cement is mainly due to the difference in potential phase composition of clinker such as C2S, C3S, etc., the addition of Pozzolana to cement manufactured will not hold good for any cement gradation for PPC. But PPC should meet out OPC 33 Grade strength on curing for 28 days as per BIS.
PPC is the best in many places especially in saline environment and in coastal areas. However, many people continue to use OPC due to the fact the differential price is very less and a little more faster setting characteristics of OPC cement. The building made of proper PPC(preferably flyash based in India) is more superior to that of OPC mainly due to structural development of cement bonding.
I think PSC (Portland Slag Cement) Which was made of from Slag.(Slag is a by product of Steel) which fight with agravate element of soil like Sodium, Pottacium.aliali silica reaction.
But in PPC which was made of Pozolona (Fly ash basedcement) which has no power to fight to aggravate element. but it has quick setting but high early strength in Cement hydrates fast, liberates more heat. •CSH gel formed at high temp. is porous , distributes unevenly. •CSH gel forms a layer around unhydrated cement grain,hindering further hydration.so it is not durable for construction.
About OPC it is not available n market.
So it is best to use PSC-in coastal belt in India . If PSC not available in Other part of india tha used PPC .
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