Environmental Matters
Sustainability is the cornerstone of Reco Cement’s corporate mission. We operate in an environmentally responsible manner, manufacturing products that have a minimal impact on the environment. We are fully committed to the development and widespread use of green construction materials.
Our additives are made primarily from coal waste byproducts generated by other industries, byproducts that would normally be placed into landfills. Additionally, the use of our additives facilitates the use of other waste byproducts generally placed in landfills such as fly ash and granulated slag.
Unlike Portland cement, the production of Reco Cement’s additives does not require the use of energy intensive kilns. These kilns are unnecessary because our additives serve as a partial replacement for Portland cement; they reduce the amount of carbon dioxide emissions generated through the production of Portland cement on a pound-for-pound basis.
Why Use Coal Fly Ash
1. Fly Ash Definition
When power plants burn coal to generate electricity, about 10% of the inorganic materials in the coal do not burn off. These by-products are called fly ash. U.S. power plants generate approximately 71 million tons of fly ash each year, of which only 32 million tons are put to beneficial use. Most unused flay ash is either placed into landfills or retention ponds. When the fly ash in landfills or retention ponds is not maintained properly toxic materials within the ash leaks out and pollutes the water table.
2. History
Construction contractors have included fly ash as a partial replacement for Portland cement in concrete for decades. Even the Hoover Dam was made with concrete that included fly ash. When fly ash is added to concrete it actually strengthens the concrete mix. However, until recently the maximum amount of fly ash that could be added to a concrete design mix was capped at 15% of the total volume. Any fly ash added beyond that point would weaken the concrete mix. Construction contractors that use Reco Cement’s additives can use fly ash to replace up to 60% of the Portland cement they are using in their design mixes without any loss of strengthM. A typical blend might consist of 15% Reco Cement additives, 35% Portland cement and 50% fly ash.
3. Quality of Fly Ash
The quality of fly ash is determined by the efficiency with which it is burned. Most modern power plants generate Class C fly ash, which is the fly ash most commonly put to beneficial use. Older power plants generate the less desirable Class F fly ash. However, Reco Cement’s additives will work with either fly ash.
4. Off-Spec Fly Ash
Reco Cement has successfully tested its additives with Off-Spec fly ash, a subcategory of Class C fly ash. It is created when coal-burning power plants burn coal at low temperatures in an effort to lower their CO2 emissions. Off-Spec fly ash has a high carbon and calcium content, which previously eliminated it from use with cementitious materials. The carbon within Off-Spec fly ash absorbs air-entraining admixtures in freshly mixed concrete, making it very difficult to control entrained air. As a result, most Off-Spec fly ash is either placed into road beds or landfills. The reason that the Off-Spec fly ash works so well with Reco Cement’s additives is that the higher strengths produced by the additives offset the negative effects of the high carbon content.
5. Beneficial Use
The EPA has stated that the use of fly ash as a partial replacement for Portland cement in the production of fly ash constitutes an appropriate “beneficial use” of the substance. The EPA has defined "beneficial use" “as the reuse of CCRs (coal combustion residuals) in a product that provides a functional benefit; that replaces a product made from virgin raw materials on the market, thus conserving natural resources that would otherwise need to be obtained through practices, such as extraction; and that meets relevant product specifications and regulatory standards. An encapsulated beneficial use is one that binds the CCRs into a solid matrix that minimizes their mobilization into the surrounding environment.”
When fly ash is used (encapsulated) to make concrete the toxic properties of the fly ash are rendered inert.
Lower Emissions
Portland cement has an adverse impact on the environment. The cement industry produces approximately 5% of all global man-made CO2 emissions. Half of these emissions are from chemicals processed during the production of Portland cement while the other half come from burning fuel in high temperature kilns. The first step in the manufacture of Portland cement involves the cracking of limestone in high temperature kilns, a process that releases a huge amount of carbon dioxide. Producing one ton of Portland cement generates one ton of CO2 emissions.
The production of Reco Cement’s additives generates minimal CO2 emissions because they are dry-mixed and do not require the use of kilns. Construction contractors reduce their carbon dioxide emissions on pound-for-pound basis by using Reco Cement’s additives and fly ash (or granulated slag), which serve as a volume replacement for Portland cement.
Performance Characteristics
Reco Cement’s additives are qualitatively equal or superior to the performance characteristics of Portland cement.
Reco Cement’s additives have been certified to ASTM C595 “Standard Specification for Blended Cements” by two independent laboratories. The laboratories tested Reco Cement design mixes using rapid freeze-thaw testing (ASTM C 666) and deicer scaling resistance testing (ASTM C 672) to find the following results:
- Concrete mixtures utilizing Reco Cement’s design mixes did not require air entrainment or moist curing (only air curing), yet were as durable as the control concrete specimens they were tested against
- Reco Cement concretes had significantly lower chloride ion permeability denser than the control concrete specimens
- The concrete specimens containing Reco Cement’s additives had a higher compressive strength; 7,410 pounds per square inch (PSI) versus the 5,140 PSI achieved by the control specimens, and did not show any signs of reduced resistance to chemical attack
Additionally, Reco Cement’s design mixes have produced cements and concretes that are:
- Stronger and sturdier than conventionally produced products, partially due to the elimination of thermal cracking;
- The workability of the design mixes are comparable to those achieved by Portland cement;
- The design mixes set faster and more efficiently due to a lower need for cooling in large pours and no need for accelerators in the hardening phase;
- Unlike Portland cement, our design mixes do not require the use of caustic chemicals.
Reco Cement routinely achieves results in excess of 9,000 PSI, depending on the quality of the Portland cement and fly ash supplied by the client.
Recycled Materials
Reco Cement’s additives are made primarily from recycled materials that are usually sourced locally. If the materials are not recycled into our design mixes they would normally be placed into landfills. The materials include crushed glass, calcium carbonate and lime kiln dust, gypsum, oil shale and coral dust. Each design mix will contain unique admixtures to produce a blend specific to the needs of the customer. Additionally, the use of Reco Cement’s additives allows Portland cement manufacturers and ready-mix companies to use more fly ash and granulated slag in their design mixes.
Lower Cost
Reco Cement additives can reduce costs for Portland cement manufacturers and the ready-mix companies in the following ways:
- Reco Cement’s additives are made primarily from recycled materials that are locally available at prices significantly lower than the price of Portland cement.
- Using our additives also allows users to include recycled materials such as fly ash and granulated slag in their design mixes. Both materials are available at prices significantly lower than the cost of Portland cement.
- The production of Portland cement requires high temperature kilns that consume vast quantities of expensive energy resources. Reco Cement’s additives are produced through a highly automated, low labor process that does not require energy-consuming kilns.
- The cost of adding one ton of annual capacity to a Portland cement plant is approximately $150 to $250 per ton. While the cost of building a factory that produces Reco Cement additives is approximately only $10 to $12 per annual ton of capacity.
Portland cement factories are physically tied to their kilns, while Reco Cement’s factories are easily disassembled and moved to another location if market conditions change.
The 10 largest coal producers and exporters in Indonesia:
- Bumi Resouces
- Adaro Energy
- Indo Tambangraya Megah
- Berau Coal
- Bukit Asam
- Baramulti Sukses Sarana
- Harum Energy
- Mitrabara Adiperdana
- Samindo Resources
- United Tractors
Source: Reco Cement
