What to look for when using fly ash in precast products.
NOTE: An updated version of this article is available. Please click here to access it.
By Arnie Rosenberg
Dr. Arnie Rosenberg is a former research director at Grace Construction Products and now a guest researcher at the National Institute for Standards and Testing, working on the characterization of fly ash.
All precast concrete producers can now use a group of materials called “fly ash” to improve the quality and durability of their products. Fly ash improves concrete’s workability, pumpability, cohesiveness, finish, ultimate strength, and durability as well as solves many problems experienced with concrete today–and all for less cost. Fly ash, however, must be used with care. Without adequate knowledge of its use and taking proper precautions, problems can result in mixing, setting time, strength development, and durability.
What Is Fly Ash?
Fly ash is a group of materials that can vary significantly in composition. It is residue left from burning coal, which is collected on an electrostatic precipitator or in a baghouse. It mixes with flue gases that result when powdered coal is used to produce electric power. Since the oil crisis of the 1970s, the use of coal has increased. In 1992, 460 million metric tons of coal ash were produced worldwide. About 10 percent of this was produced as fly ash in the United States. In 1996, more than 7 million metric tons were used in concrete in the U.S. Economically, it makes sense to use as much of this low-cost ash as possible, especially if it can be used in concrete as a substitute for cement.
Coal is the product of millions of years of decomposing vegetable matter under pressure, and its chemical composition is erratic. In addition, electric companies optimize power production from coal using additives such as flue-gas conditioners, sodium sulfate, oil, and other additives to control corrosion, emissions, and fouling. The resulting fly ash can have a variable composition and contain several additives as well as products from incomplete combustion.
Most fly ash is pozzolanic, which means it’s a siliceous or siliceous-and-aluminous material that reacts with calcium hydroxide to form a cement. When portland cement reacts with water, it produces a hydrated calcium silicate (CSH) and lime. The hydrated silicate develops strength and the lime fills the voids. Properly selected fly ash reacts with the lime to form CSH–the same cementing product as in portland cement. This reaction of fly ash with lime in concrete improves strength. Typically, fly ash is added to structural concrete at 15-35 percent by weight of the cement, but up to 70 percent is added for mass concrete used in dams, roller-compacted concrete pavements, and parking areas. Special care must be taken in selecting fly ash to ensure improved properties in concrete.
Standards
There are two classes of fly ash: “F” is made from burning anthracite and/or bituminous coal, and “C” is produced from lignite or subbituminous coal. In Canada, there is a further distinction. When the lime content is 8-20 percent, it is classified Cl, and when it is higher, it is class C.
In the United States and other parts of the world where U.S. standards have been adopted, the chemical part of the specification requires only a combined total of silica, alumina, and iron oxide. It does not specify the amount of silica that reacts with lime to produce added strength. The alumina content could be high in fly ash, which could be detrimental because more sulfate to control its reactivity might be required. Sulfate is added to the cement to control only the setting reactions of the aluminates and ferrites in the cement. However, the amount is limited because expansive reactions are possible after the concrete has set. This amount of sulfate does not take into account the extra aluminates that can be added when fly ash is used. Too much iron oxide will retard the setting time.
Although in ASTM C618, the loss on ignition listed in the table of requirements is less than 6 percent, a footnote actually allows up to 12 percent. Incomplete combustion products such as carbon, which affects air entrainment, water-cement ratio, set, and the concrete’s color, could cause this ignition loss. Fly ash is considered to have met C618’s requirements if the 7- or 28-day strength of a sample with 20 percent fly ash reaches 75 percent of the control strength in an ASTM C109 test.
Both class C fly ash and slag have about 35 percent silica and much lower calcium oxide than portland cement. In most cases, lower calcium oxide means better durability. In some fly ash, alumina and iron oxide can be quite high, leading to lower strength and unusual setting time problems. The carbon content was reported in some to be so high that it was beyond the special footnoted exception in ASTM C618.
Advantages
The advantages of using fly ash far outweigh the disadvantages. The most important benefit is reduced permeability to water and aggressive chemicals. Properly cured concrete made with fly ash creates a denser product because the size of the pores are reduced. This increases strength and reduces permeability.
Today, there are at least two ways to make fly ash more beneficial: a dry process that involves triboelectric static separation and a wet process based on froth flotation. These procedures generally lower the carbon content and the LOI of fly ash. The cost of an additional storage bin should be easily covered by the reduction in the cost of the concrete and the added benefits to the concrete. Low-carbon fly ash or the use of a better air-entraining agent at a higher-than-usual addition rate can control the problem of freeze-thaw durability.
Advantages in Fresh Concrete
Since fly ash particles are spherical and in the same size range as portland cement, a reduction in the amount of water needed for mixing and placing concrete can be obtained. In precast concrete, this can be translated into better workability, resulting in sharp and distinctive corners and edges with a better surface appearance. This also makes it easier to fill intricate shapes and patterns. Fly ash also benefits precast concrete by reducing permeability, which is the leading cause of premature failure. The use of fly ash can result in better workability, pumpability, cohesiveness, finish, ultimate strength, and durability. The fine particles in fly ash help to reduce bleeding and segregation and improve pumpability and finishing, especially in lean mixes.
Advantages in Hardened Concrete
Strength in concrete depends on many factors, the most important of which is the ratio of water to cement. Good quality fly ash generally improves workability or at least produces the same workability with less water. The reduction in water leads to improved strength. Because some fly ash contains larger or less reactive particles than portland cement, significant hydration can continue for six months or longer, leading to much higher ultimate strength than concrete without fly ash.
There have been several cases in which the early strength of concrete was low, particularly where a significant portion–30 percent or more–of the portland cement was replaced with fly ash. This need not be a serious problem today, since set time is also controlled by many other factors that can be altered to compensate for added fly ash, if necessary.
The observed slow set and low early strength obtained with fly ash has caused a reduction in the amount of this mineral admixture used in concrete. Although some fly ash materials will reduce early strength and slow the setting time it does not have to be the case today. Some fly ash actually accelerates set. The addition of accelerators, plasticizers and/or a small amount of additional CSF, as well as the proper beneficiated fly ash, can mitigate this problem.
Properly proportioned concrete containing fly ash should create a lower cost. Because of the reduced permeability and reduced calcium oxide in properly selected fly ash, it should be less susceptible to the alkali-aggregate reaction. Sulfate and other chemical attacks are reduced when fly ash is added. Fly ash, which has little effect on creep, has been suspected of contributing to corrosion because it reacts with the calcium hydroxide. Fly ash, in fact, does not materially reduce alkalinity, and the reduced permeability helps to protect the concrete from chloride penetration, the cause of rebar corrosion (see Rosenberg’s article on corrosion in the Fall 1999 issue of MC Magazine). A superplasticizer combined with fly ash can be used to make high-performance and high-strength concrete. Concrete containing fly ash generally performs better than plain concrete in drying shrinkage tests.
Disadvantages
The quality of fly ash is important–but it can vary. Poor-quality fly ash can have a negative effect on concrete. The principle advantage of fly ash is reduced permeability at a low cost, but fly ash of poor quality can actually increase permeability. Some fly ash, such as that produced in a power plant, is compatible with concrete. Other types of fly ash must be beneficiated, and some types cannot be improved sufficiently for use in concrete.
Some concrete will set slowly when fly ash is used. Though this might be perceived as a disadvantage, it can actually be a benefit by reducing thermal stress. When cement sets, it produces 100 calories per gram so that the temperature of a structure may rise 135 degrees. Certain fly ash can be used to keep the temperature from rising too high (less than 45 degrees). However, concrete with fly ash can set up normally or even rapidly, since many other factors control the set and strength development.
Freeze-thaw durability may not be acceptable with the use of fly ash in concrete. The amount of air entrained in the concrete controls the freeze-thaw durability, and the high carbon content in certain fly ash products absorbs some air entraining agents, reducing the amount of air produced in the concrete, making the concrete susceptible to frost damage. High-carbon fly ash materials tend to use more water and darken the concrete as well. It is not recommended to use a high-carbon (greater than 5 percent) content fly ash, but if it must be used, the proper air content can be reached by increasing the dosage of an air-entraining agent.
Slow set and low early strength need not be consequences of using fly ash. Most of the time, high- fineness and low-carbon fly ash will result in high early strength. Sometimes, additional lime, an accelerator or a superplasticizer will be needed. Fly ash also can be mixed with a small amount of condensed silica fume (CSF) to improve set or early-strength properties. Certainly, careful attention to the mix design and water content is always necessary to obtain proper set and early strength development.
Precasters should try to obtain fly ash with as high a silica content as possible. Silica reacts with lime from cement to produce strength and reduce permeability (class F fly ash should have 50 percent silica content; class C should have 35 percent silica content).
Ask that the water requirement be less than the control, that the color, density and fineness have a minimum variation (<5 percent) and that the strength activity index at 3, 7 and 28 days be 90 percent of the control. If protection from the alkali aggregate reaction is needed, then the fly ash should be tested in ASTM C 441 with 25 percent of the cement replaced with the fly ash. Some class C fly ash will not protect against the alkali-aggregate reaction. Lastly, it is important for the precast concrete producer to test the mix design continually, because fly ash is a group of materials that comes from burning coal.
IT IS 1 OF THE BEST INFORMATION OVER THE FLY ASH. THANK YOU SIR.
Dear Sir or Madam,
I was wondering if you could help me for finding out a recipe of concrete that use for wall precast semi-wet. I would like to fabricate wall panel (L=3.7 m * Depth =9 cm * Width =60cm) for using it in house. I would like to obtain the recipe for Cubic Meter .
all the best
very informative… thanks
The such information related fly ash is very useful for my carrier,
Please send me info how much qty of cement with replace fly ash for making 1 cub. concrete .
Please send value able information regarding fly ash.
I’d be glad to, Rejendra. What specific information about fly ash are you seeking?
Hi have a good night.
I am here ahsan from Pakistan and we have huge quantity of coal power plant fly ash. I want to know how how much quantity of port land cement can be replaced with fly ash to achieve the same strength. can some please help me to provide me the ratio of fly ash content in concrete like C15, C30, C40 etc
Thank you for the response, Rajendra. Please look around our website for fly ash white papers and articles. You can search for these by typing “fly ash” in the search bar near the top of each web page. Otherwise, I’d recommend contacting a precast manufacturer near your location. Since we represent North American manufacturers, we don’t have the resources and knowledge about quality and production practices that are commonly used in Pakistan.
Hi,
I use fly ash from a near by company which uses coal fired boiler.
The ash is tan in color and I doubt that I could not replace cement. Please advice on this. Is tan color flyash is good or not?
Hi Mr. Davis,
Here is a reply from Claude Goguen, our Director of Technical Services.
Fly Ash is generally a grey or tan color, so I would not rule out the effectiveness of this material based on what you have stated. You should ensure that the fly ash meets the physical and chemical requirements of ASTM C618 or other applicable specification in your area.
If you have further questions, please let us know.
Very informative. I need some information regarding procedure of manufacturing fly ash concrete and exact proportion of each component. Also the best proportion of constituents for strength and enhance properties.plz reply as soon as possible.
[email protected]
Dear all Thanks for usefull info. I’m facing some problems with flyash now. I manufacture Aerated Concrete blocks with cement : Flyash ratio approx 40:60 , last week i got flyash which was slightly green tinted (colour like cement). and with this flyash i made 14 batches of 0.6 Cubic meter mix. out of which 12 batches are failed. ( cement set in same time but strength was not sufficient to hold the aerated bubbles. adn after 2-3 hours of casting, all bubbles trapped in slurry came up and free in air.)
I think its because of cement anf flyash did not properly bonded.
from past year I’m producing aerated blocks. this problem occures this time only.
density of this flyash is approx 1.25 and older flyash is around 1. Also it required less water than regular mix. may be it is moisture….
please help me .. tell me some simple tests of flyash which i can do it at my plant.
… or so …….
Should fly ash be used in a 22″ Slab on Grade warehouse floor?
Greetings ASP,
My initial reaction is yes, fly ash can be used for such an application, and I believe it is used for such concrete pours. There are many benefits fly ash can provide such as decreased porosity, added abrasion resistance and reduced bleed water. Of particular benefit for this large slab thickness is a fly ash mix could provide a reduced heat of hydration which also assist in reducing some shrinkage cracking, etc. However, if the ambient temperature is very cold the fly ash benefit mentioned above could be a disadvantage as the fly ash will retard the curing process and depending on some mix proportioning could also adversely affect the air entrainment. Consequently, there are certain cautions and best practices which you should be aware of to insure the best results and to secure the economic and environmental benefits of fly ash use. Be sure you or your concrete producer obtains their fly ash from a high quality intermediary source as fly ash properties can have some variability depending on the original source material (i.e. power plant production).
If you have not come across them already there are two excellent articles published by Concrete Construction regarding this specific subject that outline important considerations when using fly ash in a floor situation. They can be found at:
http://www.concreteconstruction.net/concrete-construction/adding-fly-ash-to-concrete-mixes-for-floor-constr_1.aspx
http://www.concreteconstruction.net/sustainability/building-sustainable-floors.aspx
Another interesting article from Plant Services.com dated 2010 described an issue regarding some issues cropping of with respect to flooring adhesives when placed on concrete floor mixes with high levels of fly ash (exceeding 35% cement replacement). This older article stated “the American Coal Ash Association and the flooring industry have been working together to address this problem … “. I do not know if more current information is available.
Since this is a cast-in-place condition a good source of information might come from your local ready-mix manufacturers association or the national association at: http://www.nrmca.org/aboutconcrete/cips/
Eric A. Carleton, P.E.
Vice President of Technical Services
NPCA
I was wondering if you could help me for finding out
* Test for identifying the qty of fly ash used in the concrete/ concrete products.
• Test for analyzing unknown concrete sample to what amount of each ingredients present
• Test method using optical microscopy / equivalent technique on thin sections of concrete to determine the fly ash content
Is concrete with fly ash useful in curing?
Is it require less water for curing? Which type of curing is required
Thank you for the questions, Dheeraj. Claude Goguen, an engineer in our technical department, provided the following answer: “Fly ash has pozzolanic properties and the pozzolanic reaction is generally slower than cement’s hydration reaction. Therefore, the use of fly ash can retard initial set which may sometimes result in delaying finishing operations. This depends on the type of fly ash you use. Class F fly ash will most likely increase setting time while class C is unique because it may either accelerate or reduce set time depending on the specific properties from the original fossil fuel. The effect on set also depends on the amount of fly ash replacement in the mix. Higher amounts can lead to significant retardation of initial set.
The use of fly ash will generally lower the heat of hydration in comparison with mixes using only portland cement. Fly ash in concrete may also lead to lower early age strengths. This also varies depending on type of fly ash, and replacement levels. However, fly ash use in concrete has been shown to increase long-term strength.
To answer your questions specifically, fly ash is generally not used to enhance curing. It has many other benefits including lowering water demand, increasing workability and reducing bleeding and segregation. It also enhances concrete’s hardened properties by increasing long term strength, lowering permeability and increasing overall durability. It will not require less water for curing. Actually when high levels of fly ash are used, more moist curing may be required. I am not aware of a specific type of curing associated with fly ash use as opposed to curing of concrete with portland cement only. As with all curing, maintaining ideal temperature and relative humidity is key to allow both pozzolanic and hydration reactions to occur.”
greetings,
m a B.E student and m doing a project on flyash, bt m not getting exactly what i shud do, what new i should do related to flyash. can any1 help me out?
thank you.
Thanks for the comment Sarfarez. What specific questions do you need more information on for your project?
How can i collect data on how to use fly ash in concrete? May you please send me the whole project on how to use fly ash in concrete through my email address
Thank you for the comment Anitha. I’d be happy to help send some information to help you with your project. Please reply with specific questions you have about fly ash, and I’ll forward those to our technical services department to answer.
There is also Thermal Beneficiation which is not mentioned. Processes such as SEFA’s STAR creates a fly ash product that eliminates all organic matter, and has the same air-entrainment characteristics as straight cement mixes.
it was really helpful for my project.
Hello,
I am a MSc student looking to do a project on fly ash and how it affects formed concrete such as Hollow core or Waffle as opposed to a solid slab.
Do you have any performance information, or a way to calculate it, when fly ash is used in this way and how it effects the performance of the end slab?
If you send any information through to my email address that would be excellent
Thanks
Thanks for the comment Alex. If you search “fly ash” on our website there is a wealth of material and articles available for you to use for your school research. Please let me know if you have anymore questions.
Which gives higher strength for concrete sand or fly ash?
It is good information for studys
I am a m.tech student doing research on concrete made with flyash. I am not using cement. How to determine water to flyash ratio in the mix.and setting time too. Please help
Thank you for your comment Uma. We have many resources available to use for research on fly ash on our website. I’d recommend using our main search bar located at the top of the site to search for fly ash related articles, tech notes, white pages and more. If you still need help with a specific technical question, I’m happy to forward that to our technical services engineers for a response.
why fly ash gives strength after 28 days
Umair
Thank you for the comment. I forwarded your question to our Technical Services engineers. The following response is from Kayla Hanson:
Fly ash helps increase strength development after 28 days, and in some cases months-to-years beyond 28 days, because of the way its reactions occur. When ordinary portland cement reacts with water, the products include calcium silicate hydrate and lime. Calcium silicate hydrate (abbreviated CSH; not its chemical formula) is the main contributor to concrete strength, while lime’s strength contributions are negligible until it’s reacted with another material to produce CSH. Fly ash is a pozzolan and it reacts with the free lime to produce additional CSH. As cement hydration continues, more CSH and more lime is produced. In the presence of fly ash, the lime can react with the ash to produce additional CSH. This can continue as long as the reactants are available in suitable quantities and other environmental factors are favorable.
I’m using Fly Ash type F from Pozolan so i’m facing issue that the water demand has increased
please advise send me email.
Haitham,
Thank you for the comment. I forwarded your question to our Technical Services engineers. The following response is from Kayla Hanson:
Good quality fly ash generally reduces water demand. The Portland Cement Association document, “Optimizing the Use of Fly Ash in Concrete,” states, “Although the exact amount of water reduction varies widely with the nature of the fly ash and other parameters of the mix, a gross approximation is that each 10% of fly ash should allow a water reduction of at least 3%.
“Coarser fly ashes or those with high levels of carbon generally produce a smaller reduction in water demand and some may even increase water demand.”
We would recommend you evaluate the fly ash you are using for carbon content and fineness. You should also reevaluate your mix design to ensure the proportions are appropriate, to verify batching sequence, and also to ensure that all the constituent materials are suitable for combined use.
why Fly ash concrete designed to be equivalent in
strength to ordinary concrete at 28 days will
normally exhibit slightly lower strength at early
ages.?
Thank you for the comment. I forwarded your question to our Technical Services engineers. The following response is from Kayla Hanson.
Using fly ash typically results in lower early-age strengths when compared to concrete of equivalent design strength made with ordinary portland cement.
When hydraulic cement and water react, the main products are calcium silicate hydrate and calcium hydroxide. Calcium silicate hydrate is the biggest contributor to strength, while calcium hydroxide contributes little to no strength. Fly ash is a pozzolan, and it reacts with calcium hydroxide and water. So for fly ash to begin its cementitious reactions, it first needs cement and water to react and create calcium hydroxide. The fly ash needs to wait for calcium hydroxide to become available, so this causes a slight delay in early strength development.
The amount of fly ash used in a mix design also determines how much or how little early strength gain will be affected. The rate at which fly ash reacts also is dependent upon the coal the fly ash came from and the amount of silicon dioxide, aluminum oxide and iron oxide. Heat of hydration also affects early strength gain. Class C fly ash can have varying effects on reaction rates and heat of hydration, but Class F fly ash usually gives a lower heat of hydration. Reaction rates typically increase to a certain point with increased heat, so lower heat of hydration can retard reaction rates to an extent too.
As time progresses, concrete made with fly ash continues to increase in strength beyond 28 days. In some cases, concrete made with Class C fly ash will have the same strength at 28 days as concrete made with ordinary portland cement. It depends on so many different factors. However, in general, beyond 28 days, strength development in concrete made with ordinary portland cement will taper off to a much slower rate, while strength development in concrete made with fly ash will continue at a faster rate.
Thank you for the informative article. My question is regarding the increased strength of concrete when fly ash is added particularly in dam construction. Do the rare earth elements found within the fly ash contribute to the increased strength and durability of concrete? If the REE were removed would fly ash be as attractive an additive to concrete?
Thanks.
Thank you for your comment Dale. I forward your questions to our Technical Services engineers. The following response is from Kayla Hanson.
The rare earth elements found in fly ash contribute little, if at all, to concrete’s strength.
Fly ash’s contribution to concrete is centered around its pozzolanic, and sometimes hydraulic, behavior. Fly ash’s behavior is largely dependent upon the composition of the coal from which the fly ash was created. According to the Portland Cement Association, fly ash can have glass contents ranging from about 50% to 90%, depending on the coal that was used and the manufacturing process. In low-calcium fly ash (generally Type F), many of the other materials do not react in concrete – only the glass will react with water in the presence of calcium hydroxide. As the calcium content increases (closer to the levels in Class C fly ash), the composition of the glass can change, making it more reactive. In some cases, this enables the glass to react with water alone, giving it hydraulic properties as well as pozzolanic properties.
However, I’m unfamiliar with the rare earth element-extraction processes that are being researched. There could be a possibility that the extraction methods alter the structure of the ash, which could affect its behavior. The usability, or incorporation methods, could also be affected. For more information about rare earth element-extraction from fly ash, I recommend contacting the American Coal Ash Association.
Sir
Is there any difference in fly ash used in bricks and fly ash required for concrete purpose
Thank you for the comment Yashwant. We have several resources available on our website about fly ash and the role it plays to enhance concrete’s strength. If you can provide a bit more information about the project you are working on, I’d gladly direct your specific questions to our technical services engineer for a response.
Question..
as known, the maximum allowable of cement replacement is 70%. since the over use of cement replacement may reduce the alkalinity of concrete and then leads to steel corrosion, what will be the PH or alkalinity of concrete at the dosage of maximum cement replacement?
Thank you for your comment Ameen. Concrete made using portland cement usually has a pH value of about 11-12. High volumes of fly ash may decrease the pH, but by how much varies. I would recommend contacting the Portland Cement Association, ASTM International or the American Concrete Institute for more information. They would be able to better help you with the material properties of your high-volume fly ash concrete. If you do have anymore questions, please let me know.
can anyone tell me about how much strength increase if we use fly ash as construction material instead of cement material?
Thank you for your comment akash chovatiya. I forwarded this to our technical services engineers. The following response is from Mitch Rector.
The key benefit for adding fly ash to a mix is it provides a pozzolanic reaction where the silica in the fly ash will react with the available lime and alkali, creating more cementious products. This will increase the long-term strength of the concrete at a cost of slightly lower early strength.
It is hard to give a precise strength estimate without knowing the details of your mix. However, high-quality fly ash will typically result in higher long-term strengths when used in addition to Portland Cement. Use of fly ash will also result in reduced permeability and increased durability of the concrete. Click here for more information.
If you are looking for information about 100% fly ash usage, Montana State University conducted research that had concrete reach 4,800 psi, 28-day strength with 100% fly ash use. You can click here to find more information on their research.
In addition, The Portland Cement Association has a document titled “Optimizing the Use of Fly Ash in Concrete” that discusses more about the properties of concrete containing various levels of fly ash.
I am planning to mix coal ash to concrete mixture for road concreting. Please help on the proper mixing proportion and ratio. What quality of coal ash shall i use. Please help me.
Thank you
Thank you for your comment John. We have many resources available to use for research on fly ash on our website. I’d recommend using our main search bar located at the top of the site to search for fly ash related articles, tech notes, white pages and more. If you still need help with a specific technical question, I’m happy to forward that to our technical services engineers for a response.
Thank for sharing your knowledge about fly ash. Your content is so informative and awesome. Keep Sharing!!
Would like to know ifburning house hold garbage fromaland fill can we make fly ash
Robin, thank you for your comment. I recommend contacting the American Coal Ash Association about your inquiry. They will have better resources to give you a proper response. If you do have any questions regarding fly ash in concrete, this article is a great resource or search “fly ash” on our website for more information. Thank you!
Fly ash improves concrete’s workability, pump ability, cohesiveness, finish, ultimate strength, and durability as well as solves many problems experienced with concrete today–and all for less cost. Well, this part I like as I am also into concrete business and will be helpful.
May I know the effect of flyash on adhesion of concrete mortar to its surface ??
As per my finding
More replacement of cement with flyash leads to less adhesion when we are using additional admixture like rd , mhec etc
Thank you for the comment Ambar. Here are a couple other recent articles we’ve written about incorporating fly ash in your concrete mix design – Material Matters: Fly Ash and SCMs in Concrete. If you still have questions regarding fly ash, let me know and I can forward them to our technical services engineers for a response.
Very nice to read all comments , I also have a plant to making fly ash bricks , it is very important to ask as which is the best chemical in Industries to make fly ash bricks hard and strong as even quality of fly ash low or cement being used as lower, I using Emami cement till today, but my bricks is not being hard and strong as I want??
Your content is informative and awesome. Thanks for sharing your knowledge about fly ash. Keep Sharing!
Great post indeed, I loved to read it as it provides all the necessary details of what I was searching for. Thanks for great information you write it very clean. I am very lucky to get these tips from you.
Thanks for writing this great article for us. I have gained good stuff from this website. Looking forward to your next article. I am happy to share this post to my friends. Keep it up.
I really appreciate that you shared this amazing post with us, thanks for sharing and keep up the amazing work.