aac versus clc

8/11/2019 Aac Versus Clc

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Comparison Between AAC Blocks and CLC Blocks

To answer the most common question people ask me, should I manufacture AAC* blocks or

CLC^ blocks? here I am with the promised guide about comparison between AAC blocks and

CLC blocks. I hope it helps my audience to decide the right product for them. I have tried to

compare both products on various parameters. This by no means is an exhaustive list, but it

might help to guide your decision making process in right direction. Ill include some moreparameters soon. Kindly go through it and let me know your views. I would be glad if this guide

helps you decide on the right kind of lightweight block. So here is first episode in comparison

between AAC blocks vs CLC blocks.

Note: Kindly post your CLC related queries on our discussion forum. I have set up a dedicated

topic to deal withCLC blocks and related queries.This would be like one stop solution for

anybody looking for information related to CLC blocks.

1. Production capacity

Generally production capacity of CLC blocks ranges from 20 to 80 m3/day. This relatively smallcapacity is result of various factors which I have discussed below. In case you want to ramp up

production, then there is very little you can do other than replicating the manufacturing line.

Production capacity of AAC blocks starts from 160 m3/day and goes all the way up to 1500

m3/day depending on client requirement. But most of the plants in India have production

capacity in range of 500-1000 m3/day. For those who want to set up their first AAC plant, I

would recommend 350-500 m3/day as initial capacity. Of course it can be scaled up later on

without much hassle and little bit of extra investment. Going for capacity smaller than 350

m3/day is not advisable as there is very small difference in terms of investment since except for

extra autoclaves; rest of the equipment stays the same.

So, if you are looking for a expandable project with bigger volumes, thenAAC blocks

manufacturingis the one for you.

2. Scalability

As most of the CLC equipment is available in lower capacities, ramping up production would

require setting up a parallel line. In addition to investment, it would also call for more

manpower. Moreover like other cement products, CLC requires a total curing time of 28 days,

more space would be required to accommodate increased production. Since CLC blocks

require such long curing time, they cant be stacked up unlike AAC blocks to save space.

It is possible to increase production capacity of AAC plant just by installing more autoclaves

and some extra molds. As a matter of fact most of the equipment for plant capacity from 160

m3/day to 800 m3/day is same except for number of autoclaves and molds. These factors work

in favour of AAC as production capacity can be increased with much lower investment. AAC is

the clear winner in this section.

3. Land requirement

CLC equipment requires very less space due to compact size and smaller production capacity.

A CLC production facility requires around 350 m2 of covered space (depending on automation

levels) for protecting CLC equipment from the elements. But much more space is required forcuring CLC blocks. As mentioned earlier, total curing time for CLC blocks is 28 days. Out of
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this, wet curing is required for minimum 14 days. Moreover since green CLC blocks cant be

stacked above each other beyond a certain limit, lot of space is required. E.g. A CLC plant

producing 50 m3/day would require minimum space of 1400 m2 to accommodate 28 days

worth of blocks arranged in stacks of 1 m3 (1 m x 1 m x 1 m) each. Similarly if production is

increased by 25 m3/day, space requirement would increase by 700 m2.

On the other hand, AAC factory with production capacity of 500 m3/day requires around 5 acre(20,000 m2) of land. AAC blocks are ready to be used once they are steam cured inside

autoclaves. Due to this AAC blocks can be stacked on top of each other without worrying about

any damage. This way no additional space is required for finished goods storage even after

capacity expansion. Even while expanding the capacity of an AAC plant land required does not

increase drastically. E.g. scaling up from 160 m3/day to 240 m3/day requires less than 400 m2

of space.

A fresh batch of AAC blocks entering autoclave for steam curing

4. Investment

CLC equipment with production capacity of 20 m3/day ranges between Rs. 2-5 million

depending on the supplier and level of automation. Project cost for a 20 m3/day plant would

come to around Rs. 3.5-7 million excluding land. Since total production and hence sale of a

CLC plant is lower, working capital requirement is smaller.

Equipment cost for AAC plant of 500 m3/day would range from Rs. 50-80 million for Chinese

equipment depending on the supplier and level of automation. Similar capacity equipment from

European vendors would cost anywhere between Rs. 400-700 million. Most of the AAC

machines in India are of Chinese origin, so well continue keeping that in mind. Project cost for

a 500 m3/day plant would come to around Rs. 130-200 million excluding land. In addition to

high project cost, working capital required for AAC plants is much higher due to bigger

production capacity.

In terms of investment, AAC is clearly the most capital intensive project and recommended for

those with strong funding sources. While for those entrepreneurs who want to make smaller

investment and test waters, CLC is the way to go.

5. Manpower

A medium capacity CLC plant of 40 m3/day would require 6-10 workers in a shift (8 hours),

bringing total manpower requirement to 18-30 workers per day.
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An AAC plant of 500 m3/day would require 12-15 workers in a shift (8 hours) with total

manpower requirement to 36-45 workers daily.

Have gone through your query about CLC vs AAC and will try to give your ans related to

this query

1. As far as the quality is concerned, How does CLC compare to AAC and how does it affect

the end consumer perception when he is to make a choice?

when we take about quality concerned in CLC you can achieve various strength and density as

per the requirement of customer and In CLC you have various application apart from block. and

when it comes to customers perception that which to choose among AAC or CLC i think this is

not time for that because still AAC and CLC both are in their starting phase and as per my

vision to market every customer has its own dilemma about any product which to choose. and

also depend on your service and quality you offer. so both will work here in surat we have three

plant of AAC and 20 plant of CLC every one is getting their part of market.

2. What are the price points at which CLC and AAC blocks sell in the market?

For the price point it mainly depends on the local market it changes every state to state and

even city to city for example in Chennai CLC and AAC both selling price is round 3700 to 4000

and in Bangalore it is 4500 to 4700 so selling and costing price point is depend on local raw

material availability and their price and also make much difference on transportation too.

3. How to go about setting up this plant? What all needs to be considered before making that

investment?

first of all consider your targeted market place and find near by thermal plant and check their fly

ash quality and availability for the same and for CLC their are various plants available in market

imported and from local manufactures too and this is all depends upon your available budget

and always try to go with good plant offering best foam generator, mixture and foaming agent

as this is very important for start up because in CLC manufacturing as you learn you can

reduce the costing of blocks with your experience gain.

4. Any ideas on why are these blocks not getting enough traction in domestic market i.e. when

an end consumer buys bicks to construct his house.

As i have mention above that this is just starting of CLC and AAC in India so will take time for

consumer to adopt it. As in our city due to non availability of blocks builders do wait for blocks.

so this is matter of time but in future every one will use this blocks due to their lots of benefit.

5. Any ideas on selecting the location of plant to be setup.

As per our suggestion location of plant should be not so far from available raw material and

your targeted market because main cost adding factor for the blocks is transportation.

Nilpesh Bhadania


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1. Will CLC blocks always be more expensive than AAC blocks?

Higher cost of CLC blocks can be attributed to higher cement content (25-40%) and foaming

agent. Cost of foaming agent varies from Rs. 130-250 depending on origin and quality of

foaming agent. Similarly, quantity of foaming agent required varies from 1.5-2.2 kg/m3. These

two ingredients lead to higher raw material cost. When compared with AAC, raw material cost

of CLC is much higher. This difference in cost is offset to an extent by lower overheads of CLCproduction compared to AAC production. But even after that cost of 1 m3 of CLC is higher than

that of AAC.

2. Weight and water absorption issues with CLC blocks.

Density (weight) and strength of CLC blocks can be controlled by altering the recipe of CLC

production. In fact in that regard CLC offers more flexibility by allowing blocks of various density

and strength to be produced as per requirement.

In addition to recipe, factors like strength and water absorption are also dependent on how well

CLC blocks are cured. If recipe is not right and blocks are not cured properly, then weight,compressive strength and water absorption issues might crop up.

You may also visit forum to discuss about CLC blocks in detail under topic titledCLC blocks

and related queries

Note: I dont have production experience with CLC blocks, but I have knowledge of it as a

product in class of lightweight concrete just like AAC.

Regards,

We have been into light weight concreting since a long time but were doing only in-situ

castings. We have a production capacity of 150 m3 per day which includes foam generator,

mixer, dispensing pump which can pump the material directly to the moulds.

Recently weve got an order from a reputed builder in Delhi-Ncr to produce CLC blocks for them

at their site. Their criteria for the CLC blocks is density not more than 800-850 kg/m3 & strength

not less than 3.5 mpa/mm2. We are using class 1 pond ash from the Dadri NTPC Plant & the

design mix for the same is as under:

Cement: 250 Kg.

Flyash: 250 Kg.

Water: 150 Liter.

Foaming Agent: 1:40 Ltr. protein based

Lime Water: 20 Ltr.Hardner: 1 Ltr.

Kindly suggest if the design mix is right to attain the desired results because while doing trials

for them we happened to achieve these results one or two times but are not getting it

constantly. The trials were done in cubes whereas we are trying to authenticate ourselves by

doing the same in proper mould size of 500x200x250 being stacked vertically in the height of

500. Moreover we also intend to cure the days production in a steam curing chamber for 18

hours so that we can despatch the days production on the third day. We have developed a

steam curing chamber based on the principles of Autoclave chamber. Kindly suggest

something to improve to achieve the desired results regularly.
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Please reply ASAP as the client has already started setting up the production area to start the

production immediately & we are waiting for the proper results to come up before investing in

the moulds & steam curing chamber.

Thanks & Regards,

Dixit Bajaj

09891060708

Dear Sir,

1 m3 material ratio-

flyash- 520 kg price@1000 per ton=520rs

cement-250kg price@300per bag =1500rs

foming agent-2ltr price@160 per ltr =320

wast oil use for mould 2ltr@40perltr = 80

electricity use per m3 =120

labour charges per m3 = 300

total -

2840other exp 260

-

3100

we made clc block 900-950 density.

can we replce cement and use lime.

please replay soon.

As per IS 2185, CLC density requirement is 800 kg/cbm and compressive strength should beminimum of 2.5 N/mm2. So guys, pls make sure the above important parameters are

maintained when manufacturing CLC blocks.

As per IS 2185, Density requirement for AAC blocks can be from 450-550 kg/cbm with

compressive strength of 2 N/mm2.

In hyderabad market, AAC blocks are manufactured around 600-650 kg/cbm density and

around 3-4 N/mm2 strength. Where as CLC is around 800 kg/cbm and around 2.5 N/mm2

strength.

By looking at density, you can understand that about 150 200 kg less material is required formanufacturing of AAC blocks. Even though the setup costs are high for AAC plant, one can go

upto 500-1000 cubic meter per day production capacity. This results in less overall

manufacturing cost for AAC block. The highest capacity of CLC plant in India as per our

knowledge is around 70 cubic meter per day (manpower requirement and land requirement is

much higher in this case).

Market acceptence of AAC blocks is much higher than CLC blocks even though the selling cost

of CLC blocks is always 300-400 Rs per cubic meter less than AAC blocks. Current AAC

market price is around 3400-3600 Rs/cubic meter, CLC market price is any where from 2800

3100. This is because of the following points.


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1. CLC blocks is heavier than AAC block. (4 AAC block weight is 7.5 kg, CLC block weight is

10.5 to 11 kg).

2. The edges/corners are easily damaged in clc blocks because they are naturally cured and to

reach their maximum strengh it takes around 3 months. we normally deliver the blocks in 3

weeks time.

3. AAC block looks much better (yes, looks are important to builders it seems!!!).

4. Yes, water absorption is very low in CLC blocks (around 10-12 %) compared to AAC blocks

(around 20-25%).

You can try reducing about 50 kg of flyash and 30-50 kg of cement and check the strength of

the block. This will result in density of the block to 800 kg/cubic meter compared to your 900 kg.

How much power is required for your CLC plant? our electricity cost per cubic meter is around

60-70 Rs. We are using about 1.2 liter foaming agent per cubic meter.

you can contact me for more information.

aac versus clc

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