Iraivan's Contribution to the World: Fly Ash Technology

[Professor BK Mehta speaks on the significance of Iraivan's Foundation]

Description: Professor Mehta developer of fly ash concrete for Iraivan Temple explains the process of development for Iraivan foundation to last 1000 years. This is a transcription of a talk he gave on September 25, 2010, at the Iraivan Temple Donor Appreciation Reception held at the Trader Vics Banquet Hall in Palo Alto, California. Kulapati Deva Raja, one of our senior sishya in America, introduces Professor Mehta to the audience that night. Deva is founder of Canyon Construction and long time consultant and collaborater on Iraivan temple construction and other building projects at Kauai Aadheenam. He worked closely with Professor Mehta during the years when the foundation of Iraivan temple was being planned and executed. Deva provided in-depth foot notes to Professor Mehta's talk to clarify some aspects of the project and the significance behind some of Professor Mehta's thoughts. These are found at the end of the transcript.

Deva Rajan and Professor BK Mehta

Photo left: Kulapati Deva Rajan stands with Professor Mehta who shows the monks a small tray of coal fly ash. It looks very much like vibhuti from the sacred fire.

Kulapati Deva Rajan:
Greetings everyone. Bodhinatha, swamis, distinguished guests and friends.

In early March of 1999 Gurudeva sent me to U.C. Berkeley to invite Professor Mehta to help us with the design of our concrete foundation of Iraivan Temple.

As most of you know Gurudeva wished that the Iraivan Temple would be designed and built to last 1000 years. So we needed a concrete foundation that would perform in that way, a concrete that would not crack, would not fail in any way even without steel reinforcing. So it was Professor Mehta that brought us a new concrete technology known as high volume fly ash concrete.

What is that you may ask? What is fly ash? So that's a beautiful story that we're here to find out about. Professor Mehta will tell us a very, very wonderful and important story about high volume fly ash. More...

Kulapati Deva Rajan:
Greetings everyone. Bodhinatha, swamis, distinguished guests and friends.

In early March of 1999 Gurudeva sent me to U.C. Berkeley to invite Professor Mehta to help us with the design of our concrete foundation of Iraivan Temple.

As most of you know Gurudeva wished that the Iraivan Temple would be designed and built to last 1000 years. So we needed a concrete foundation that would perform in that way, a concrete that would not crack, would not fail in any way even without steel reinforcing. So it was Professor Mehta that brought us a new concrete technology known as high volume fly ash concrete.

What is that you may ask? What is fly ash? So that's a beautiful story that we're here to find out about. Professor Mehta will tell us a very, very wonderful and important story about high volume fly ash.

P.K. Mehta is a Professor Emeritus in Civil and Environmental Engineering at University of California at Berkeley. He hold several patents and is the author of four books on concrete technology. His textbook: "Concrete Microstructure Properties and Materials" has been translated into Chinese, Japanese, Portuguese, and Spanish. He's an honorary member of the American Concrete Institute and recipient of many prestigious awards including the Berkeley Citation.

Professor Mehta lectures widely and has been invited to countries all over the world. Europe, South Africa, America, India and China; all of this to talk about this amazing new technology high volume fly ash. He's often referred to as the foremost authority in the world on concrete technology.

Please join me in welcoming Professor Mehta.


Professor P.K. Mehta:
Satguru Bodhinatha and friends.

I am very pleased to have the opportunity to personally share with you the technology of building a large foundation without any reinforcement, without joints and able to produce concrete which is free from any cracks. And, it is expected to last a thousand years which was Gurudeva's wish. Gurudeva, Sivaya Subramuniyaswami has had an intuitive role in helping us spiritually. I believe he also had some intuitive role in helping me at the beginning of a technology which is now being widely accepted worldwide and is the technology of the future building construction. (1)

Not many people know that more than half of electrical power is produced from the combustion of coal. Coal, on burning, leaves a residue which is called fly ash. It is one of the largest industrial wastes on the planet and it becomes toxic if stored in waste piles, which is the current way of handling it.

Deva Rajan approached me with : Gurudeva would like you to help us develop a concrete which would last a thousand years. It was for a temple for Lord Siva. (2) I had never designed even a driveway concrete, which was without cracking. So, this was a tall order but when he came in the name of Lord Siva I could not say no. If Lord Siva wants, we will be successful and Lord Siva will guide us.

So I undertook the project and we started in a small place (Steel Tech Corporation) in Honolulu with a laboratory testing the materials. I had an intuition that the ancient Roman technology about buildings is the only one which have been durable now because we had some Roman structures which have lasted for 2000 years. (3) That technology used lime as a bonding material in the mortar that was 80 percent lava, volcanic ash. I had thought that our coal fly ash is very similar to the volcanic ash. It's produced by man made miniature volcanoes, the same kind of action.

We obtained fly ash from the Seattle area and started experimenting. With Gurudeva's blessings, we were quite successful in building a large raft foundation, without any joints, without any steel. (4) For several years before the construction started, we observed there was not a single crack.

Now, because of the sustainability crisis in the world, and the carbon emissions, we find that if we replace half of the portland cement with coal fly ash we can build structures which are essentially crack free and we develop a very high quality concrete. So with that introduction, let me now explain it a little more.

When we developed that technology, it was not realized at that time what would be the significance of it. It took a long time and only recently we initiated a consortium of ten big U.S. universities like Stanford and M.I.T. and Berkeley, etc. They have declared that in the construction sector of the economy we can crack down a billion tons of carbon emissions every year by replacing portland cement with low carbon cements in concrete mixtures. Portland cement becomes a low carbon cement when half of it is replaced with fly ash. Right now the carbon emissions of the portland cement are in the order of two million tons, which is one of the largest carbon emitting industries implicated in the climate change.

It has proven to be the most appropriate technology now for the production of low carbon cement in concrete materials. In fact there is no other low carbon cement technology which is proven and ready for use. If we adopt this technology globally, two million tons of carbon emissions a year can be cut down immediately by half. To give you an idea, portland cement is less than 200 kilograms per cubic meter of concrete, which is about 300 pounds per cubic yard. We are using on average of about 600 pounds per yard portland cement, so it can be cut down by half.

Fresh-concrete properties are improved adding no difficulties. Workability, pumpability and finishing is very quick and very easy. (5) The strength development at twenty-eight days (the PSI) is very good and afterward it doubles, which does not happen for portland cement. (6)

(5) >

Compared to portland cement the high volume fly ash concrete at 3 to 7 days strength is lower but because of that the stresses that build up to crack concrete do not develop. By 28 days it catches up the same strength as portland cement with 600 pounds of cement and at one year the strength is almost double because micro-structurally the material is much improved.

That gives some idea of how the technology started in the U.S. As Deva Rajan mentioned, and you have seen the picture, this was a vision of Gurudeva and with his blessings we were able to develop this mix, which was very, very successful.

People in the continental U.S., especially California, heard about it and it caught on. This slab is about 120 feet long, 57 feet wide and 4 feet thick. And as I mentioned earlier, no expansion joints. We had only one concrete ready mix plant on Kauai with a capacity of 50 cubic yard per hour. We needed 500 yards a day and that was done in two mixes.

In a typical mix, 57% portland cement was replaced with fly ash. Cement was only 106 kg. (per yard) which is about 150 pounds, and the fly ash was the rest. Because of the high workability with fly ash, the water requirement was much less. That's the reason why strength went up went very well.

Another detail of the strength development is that on inspection, there are no visible cracks even after six years. This is because there's not as much water in the concrete. It can develop very high strength in the end. (6) For the hydration processes you have to protect the water, by the practice of putting a plastic sheet initially as soon as concrete was placed.

Then as I mentioned, people in California area, Oakland Park, Berkley area heard about it and they called up Canyon Construction and Deva Rajan. They would like to build some with green concrete. So it started. We developed the mixes here which Canyon Construction is able to use. This is again a typical mix very similar to Kauai. No expensive chemicals are used. For walls and flooring, it is considered excellent.

Now the cluster of important buildings for the Berkeley campus. We could convince the architect and the structural engineers that this is a very good technology, let's use it. Just like in Hawaii, at the ready mix plant, without the code, no one was willing to guarantee the strength and durability. Gurudeva personally said, "We will give you legal indemnity. You use our mix and we will take that responsibility. If it fails, you won't be responsible for strength."

We did the same thing here and in this case we did a large and deep foundation for earthquake resistance. In this case we used heavily reinforced walls, see the amount of steel here, because of the earthquake resistance renovations. The workability of the concrete is so good that it flows like water but it does not segregate. (8) That's why at the beginning we had about three thousand pounds per square inch strength at seven day but it became triple at one year. We had nine thousand pounds per square inch at one year.

This is the key feature which is attracting large scale applications of this technology everywhere. The first takers again were the owners of the temples, because they were impressed by the Hawaii foundation. The Swami Narayan started to adopt it. They again have a very large single rafts and they also did not want to have any steel joints. This is a marble temple. Instead of granite, it is carved in marble and they have built now four temples using this technology. Not only in Chicago but in Houston and Atlanta and Toronto. Very successful use.

Now, let me show you that how it is being adopted world wide. There are no codes etcetera except for what we published based on the Kauai work. This is the Chinese Olympic games. In 2006 they had to erect a tower for television transmission. They used exactly the same mix which we have published for the Barker Hall at U.C. Berkeley. Pound for pound, it was exactly the same mix. There are about two inch thick rebars in this case. It's about 1000 times bigger project than the Kauai. The workability of concrete was extremely good.

China has three to four hundred million tons of coal ash to be disposed of. India has two hundred million tons. I think it is a technology which is extremely beneficial to improve the sustainability of coal fired power plants, as well as the sustainability of the cement and concrete industry.

There is a similar project in India. They have nine ready mix concrete plants operating at the same time because of the large volume of concrete involved. The concrete flows like water and they don't need any vibrators. And so, although it is heavily reinforced, it works very well. Very quick construction and finishing. (9)

The last building of which I used the same mix exactly as the Barker Hall again was at U. C. Berkeley and in this case we could avoid 1300 tons of carbon emissions just for one good building. We saved 1300 tons of portland cement. Each ton of portland cement in the production process produces one ton of CO2. So if you save 1300 tons of portland cement by using fly ash, you save 1300 tons of carbon. If this technology were adopted for all concrete structures world wide, in a year we would be able to cut down the carbon emissions by one million tons.

In the construction sector of a country, there is no other industry which can save so much carbon emission, so quickly. This is being realized now and that's the reason why in India, Australia, South Africa and in many other countries, they are adopting it. Although we don't have any standards or codes to match up to, people use it once they realize it's very good technology.

I just wanted to share with you an unknown aspect of Gurudeva's contributions. I was a consulting participant in all this and wanted to share with you that Gurudeva had many roles to play for mankind. Thank you.


[End of transcript.]


(1) In private meetings with Professor Mehta, Gurudeva encouraged him to push forward this technology with what the professor calls, "His second half of life". The first half was his education, coming to America, teaching others as a UC Berkeley professor, then doing the research that has led to the development of this new concrete technology of "High Volume Fly Ash (HVFA). The professor was about to retire and because of the Iraivan temple foundation and Gurudeva's encouragement, he went on into a whole new career as an author, lecturer and research scientist/engineer spreading the knowledge of HVFA. So the professor is saying that Gurudeva could see or intuit this entire future career for him and how it would benefit the planet in so many ways.

(2) Mehta told me at that first meeting in his office, after hearing my long-winded proposal and invitation, that he could not say no, for two reasons: 1. He knew that he could help with the technical challenge of creating a concrete foundation without reinforcing, that would last 1000 years and 2., Because he was Hindu and a devotee of Lord Siva, he could not say "no".

(3) Here, he is referring to the Parthenon, built some 2000 years ago and is an example of the world's most durable concrete. Volcanic ash is also called Pozzolanic ash from the town of Pozzoli that was covered up and destroyed by the eruptions of Mt. Vesuvius.

(4) While working up the trial batches of HVFA in Honolulu at the Steel Tech warehouses, we also visited the structural engineer Jim Adams of JAInc. Jim actually designed the "raft" foundation concept consisting of two concrete slabs each 2' thick for a total of 4' (feet) thick. These two slabs were necessary as there were not enough trucks on the island to pour a 4' foot thick slab in one day. Originally, Jim was calling for a 3' thick foundation, but because it was to be two slabs he increased it to 4' thick. Gurudeva was thrilled with the idea of a large, thick foundation.

(5) Concrete contractors and finishers are used to standard, Portland cement concrete and don't like to change to another, unknown type of concrete such as HVFA. However, with experience, they have found that it places and flows very easily with a slightly tan instead of gray color. As it sets up, unlike conventional concrete, HVFA concrete has no "bleed" water, that's the excess water that comes up to the surface which you have to wait to dry off, before finishing. With HVFA concrete the finishers actually save time because of no "bleed" water and can go right into floating and finishing the slabs. HVFA concrete, in cold weather applications often sets up a little slower, so you have to use chemically added "accelerators" to bring it to an early set.

(6) The big difference that the professor goes on to describe is that conventional concrete comes to an early strength in 7 days with a final ultimate strength in 28 days. HVFA concrete cures much slower, remaining a bit plastic for several days, thus not cracking to thermal differentials in the slab from bottom to top as the slab cools. When conventional concrete is placed the heat of hydration causes a gain of 40 degrees. When 1/2 of the Portland is replaced by fly ash, the heat of hydration is only 20 degrees. So the stresses caused by uneven cooling are reduced by half, thus fewer or no cracking is experienced. Then HVFA concrete reaches its design strength not in 28 days but in 56 days and continues to gain strength for many months up to 3 years. If this cooling period is enhanced by curing the slab with water and burlap, as was done for the Iraivan Temple slab, the cooling is brought down in a very controlled way, at 1 degree per day.

(7) Water reducing agents called, "Super-plasticizers" are often added to the mix design, actually dumped right into the transit truck as was done for the Iraivan foundation pour. These super-plasticizers, reduce the amount of water needed to bring a stiff mix to a easily pourable mix. It is well known that the more water added to any concrete mix design, the weaker the concrete will be. So at all costs, for good durable concrete, do not add extra water.

(8) For these structures at the University of California like Barker Hall, the engineers were calling for "High Performance Concrete," normally achieved by increasing the amount of Portland cement per yard, for example, from 5 sacks per yard to seven or eight sacks per yard. The steel reinforcing on these structures called for very closely spaced bars of steel in a multiple grid layers. So the concrete used not only had to yield very high ultimate strength tests, but had to be able to flow through and in and around all of these densely placed grids of steel rebar. Through the use of "Super Plasticizers," the concrete mix design achieved high flowability without adding water and was placed without segregation of the aggregates (rock, gravel and sand).

(9) For the last ten years, Professor Mehta has been on an almost constant circuit of lecture tours, world wide. He has been invited to speak at conferences of engineers and concrete industry professionals all over India, China, Korea, Italy, Germany, Brazil, Chile, Argentina, etc. Countries that are still in the process of building their infrastructures of dams, bridges, roadways and cities are eager to learn and to apply this new concrete technology of HVFA concrete, primarily because of its better performance and durability. But it also uses up this waste product (fly ash) which comes from coal fired power plants. The disposal of fly ash is a serious problem. There are trace elements of heavy metals in fly ash and when dumped into rivers and dump sites, these toxic chemicals often leach into the underlying aquifers, polluting the drinking water.

In the introduction section of his classic text book on concrete Professor Mehta devotes his work to Lord Siva, who drank up the poisoned oceans, to save mankind, thus giving him the "blue throat". So Professor Mehta looks at HVFA in the same way, it locks up for eternity these toxic chemicals in concrete.