Este informe no está disponible en español.


Grupo Carmelo Invests For A Greener Industry

Local Company Will Commence Importation Of Fly Ash To Be Used In Concrete Products For Improved Environmental Impact


April 24, 2003
Copyright © 2003 CARIBBEAN BUSINESS. All Rights Reserved.

When an old family friend offered Melba Figueroa the opportunity to make the local construction industry greener, she jumped at the chance. Figueroa is president and CEO of Grupo Carmelo, a local aggregates and concrete products manufacturer.

University of Texas at Austin professor, Dr. Ramon Carrasquillo, gave a presentation to the local construction industry two years ago concerning the benefits of using fly ash in concrete products. Dr. Carrasquillo, an engineer and member of the American Concrete Institute, and the American Society for Testing and Materials Committee, which oversees concrete and aggregates specifications for construction, has been promoting fly ash, the mineral residue from coal-fired power plants, for use in concrete for 20 years.

Fly ash as an additive makes concrete more workable and more durable. It is the mineral deposits that are left from coal-fired electricity generating plants.

While others in the industry turned their backs on the proposal, Figueroa was paying attention.

Fly ash is not yet available in Puerto Rico but she saw an opportunity. Within two months she signed a 20-year contract with Industrial Services Group (ISG), the largest fly ash handler in the U.S. Then she negotiated a lease agreement for 3.33 acres in Tras Miramar, at Pier 16.

That was only the beginning

Just a few months ago, the scope of the project became apparent when Ecologica Carmelo raised a white 95-foot-tall dome with a diameter of 166 feet on the San Juan Bay waterfront. The landscape of Miramar was forever changed for those who travel Kennedy Avenue toward San Juan.

The dome is emblematic for Grupo Carmelo’s environmental concerns that prompted the company to enter the fly ash contract. It also represents phase one of the project and a $10.6 million initial investment.

The dome will act as a recycling and warehouse facility for the fly ash as it is vacuumed out of barges. The tunnel is below water level and leads from the waterfront to the dome. A low-pressure pump will pull the fine dust from barges at 400 tons per hour through the pipe into the sealed half-ball structure. The design incorporates the latest technologies and automated controls in dust collectors and materials handling to ensure the protection of the environment as well as to exceed all applicable federal and local environmental regulations for this industry.

For the engineers and researchers at Grupo Carmelo, the switch from local sand aggregates with cement and expensive silica additives to fly ash was a no brainer. Fly ash mixed in the concrete makes it more durable, more resistant to sulfate and salt oxidation, and more waterproof. Fly ash can be used in any product that uses cement.

Should fly ash become available as a result of a coal-fired electrical generating plant such as AES in Guayama, it will be tested to be sure it is the same Type S used for standards in concrete production. Since ISG is likely to be the handler, any Type S fly ash produced in Puerto Rico will be able to be recycled here.

"We are a small island inundated by salt corrosion," Figueroa explained. "Now, we can make more durable concrete structures and products that offer better resistance to water infiltration and corrosion thanks to fly ash."

More important, the U.S. Environmental Protection Agency (EPA) requires that fly ash be recycled under the Resource Recovery & Management Act. Federal law requires the use of concrete mixed with fly ash in every federal project wherever fly ash is available.

By June, Grupo Carmelo plans to make fly ash readily available in Puerto Rico.

The change adds a new product to the company’s line. Grupo Carmelo continues to be one of the leading raw materials and concrete products manufacturers and suppliers for the construction industry, only now it has a new and improved product.

Other concrete manufacturers will be able to send their regular cement tanker trucks to the Carmelo dome to load up on fly ash. The fly ash is pulled up from the tunnel into the dome by a giant rotating screw-like conveyer in the dome’s center. The ash slips off the screw conveyer into the dome for storage. A bucket elevator moves the fly ash to a loading silo next to the dome as needed. The entire loading system is sealed so no fly ash can escape. Waiting cement trucks will pull up onto a scale at the dispensing point so the fly ash can be automatically loaded and weighed.

The setup will include a cleaning station to vacuum clean the trucks loaded with fly ash so no residual blow off will result as trucks travel to their respective ready-mix plants. This aspect is very important to Figueroa who wants to set an example for clean standards in the local construction industry.

A sound investment

Grupo Carmelo fully expects the initial $10.5 million it has invested during troubled times for the construction industry to pay off. "Whenever the economy goes down, Carmelo invests," said Figueroa. "We want to be ready to serve the market when it takes off again."

ISG Resources Inc., the leading fly ash supplier on the mainland, shares Carmelo’s vision. They have invested millions in Research & Development, formulating new technologies for better concrete products using fly ash.

ISG’s network of fly ash sources in 31 states is linked to a network of terminals and transportation equipment. They have spent more than $35 million to manage fly ash for concrete production by building domes for ash storage at coal-fired power plants and similar loading docks for railroad cars to move the ash to meet demand. The Puerto Rico supply will arrive by sea barge.

For the past few years, researchers and engineers at Carmelo have been working with fly ash imported by the bag. Under the direction of company engineers Efrain Carreras and Ferdinand Buxo, Carmelo has been working with the U.S. Army Corps of Engineers on the technique for the construction of the Portuguese River Dam in Ponce. The Corps, which specifies fly ash in almost 95% of its projects, has approved the Rolled Compacted Concrete (RCC) technique for the dam’s construction. The concrete in the dam construction will be laid down the way asphalt is rolled out to build a road.

A new product

The introduction of fly ash into the local market by Carmelo presents another opportunity that will become phase two of the fly ash project. Carmelo has acquired the sole local license to manufacture flexcrete. Flexcrete is a fly ash product developed by ISG Resources Inc., one of several new building technologies using fly ash as the unique component.

Grupo Carmelo will invest an additional $6 million in phase two to build an additional plant in Toa Baja to produce flexcrete. The setup will be automated for the most part, only increasing Carmelo’s work force of 267 by a half-dozen or so.

Flexcrete can be manufactured into logs or thick slabs of drywall, depending on the customer’s needs. The slabs can be created anywhere from three-inches to 12-inches thick and serve as an energy saving sound barrier. The product is suitable for pre-cast manufacturing with all the attributes of fly ash including a finished surface that needs no painting.

Carmelo is working on further developments for the use of fly ash and has applied for an R&D grant from Fomento.

"We want to leave the next generation with a better concrete product than we received," Figueroa said.

Her efforts to change the industry have already been recognized by the U.S. Environmental Protection Agency. (CB March 13) Figueroa went to Washington, D.C. in March for a special ceremony where 10 firms were recognized for their leadership in this program.

Use of fly ash in concrete improves the environment

Fly ash has emerged as an additive for concrete mix that helps improve the environment.

The production of portland cement is responsible for some 7% of the world’s production of carbon dioxide, a culprit in global warming. Experts estimate that each ton of cement produced contributes around one ton of carbon dioxide emissions in the atmosphere.

The reason is twofold. A major raw material in cement is limestone, the calcination of which results in huge releases of carbon dioxide. Cement clinker production uses a terrific amount of fossil fuels to make up the other half of the damaging gas emissions.

When fly ash is used as an additive in concrete, it increases the durability and the life cycle of the product while requiring less cement and thus reducing the greenhouse gas emissions.

Fly ash comes from coal-fired electricity generating plants which grind coal to powder before burning it. The ash is the glassy mineral impurities left over after the coal has been burned.

One ton of fly ash used instead of cement saves landfill space equivalent to what an average person produces in a little over a year. The reduction in carbon dioxide produced in cement manufacturing is equivalent to two months of emissions from a car. The energy saved is enough to provide an average home with electricity for 24 days.

The use of ash in concrete is not new. The Romans first used volcanic ash in cements for construction of roads and aqueducts which have lasted for centuries. Today’s coal fly ash closely resembles that volcanic ash. It is lighter in color than cement and consists of tiny glass spheres. Fly ash particles are smaller than portland cement which allows them to flow more freely. While using less water it fills holes and blends easily with the aggregates for more durability.

When water is added to portland cement, it creates a strong binder which helps glue the aggregates together and create free lime. Fly ash reacts with the lime (calcium hydroxide) to convert it into calcium silicate hydrate--the toughest and most durable paste in concrete.

Fly ash additives serve to increase concrete performance cost-effectively, making a product that is more waterproof, more resistant to corrosive effects of the atmosphere, and longer lasting.

This Caribbean Business article appears courtesy of Casiano Communications.
For further information please contact

Self-Determination Legislation | Puerto Rico Herald Home
Newsstand | Puerto Rico | U.S. Government | Archives
Search | Mailing List | Contact Us | Feedback