As a building products company, you need a reliable source of high-grade coal combustion by-products (CCPs) as ingredients for your concrete, flowable fill and other products. We work directly with dozens of coal-burning energy producers across the United States to acquire CCPs you can reutilize in a variety of high-grade construction materials.
Look to FlyAshDirect for:
- Fly Ash – More than 60 percent of CCP production is fly ash. Modern energy plants capture these fine particulates in electrostatic precipitators or fabric filter bag houses to prevent their release from smokestacks into the atmosphere. You can use fly ash in concrete production.
- Bottom Ash – Bottom ash is coarser than fly ash and is similar in texture to sand or gravel. Use bottom ash as an aggregate in concrete and asphalt applications, granular base in pavements, and in engineered embankments and fills.
- Boiler Slag – Boiler slag is a coarse, black, angular and glassy material. Use boiler slag for blasting grit, roofing shingles, snow and ice control, etc.
- Synthetic Gypsum – Synthetic gypsum is produced when electric utilities “scrub” gasses from their plant stacks. This fluid gas desulfurization (FGD) process uses calcium carbonate or calcium oxide to remove sulfur dioxide gas from the coal combustion process. FGD results in the creation of a by-product called synthetic gypsum, which is often used in wallboard manufacturing and for agricultural soil improvement.
- Bulk Storage Rental - We offer a variety of portable storage containers to store your fly ash or other CCPs on site until you're ready to use them. Our containers are safe, secure and meet or exceed all DOT and EPA standards.
Use our high-grade CCPs in your:
Fly Ash in Concretes
Adding fly ash to your concrete mix offers you a practical, cost-effective way to increase its strength, plasticity and durability. You'll use less cement, but actually produce a superior product.
Benefits to plastic concrete:
- Improved workability – The small, spherical shape of fly ash particles provides a “ball bearing” effect that creates a concrete paste with superior plasticity.
- Decreased water demand – Replacing cement with fly ash reduces the water demand for a given slump and, in certain situations, can even reduce drying shrinkage.
- Increased pumpability – The spherical shape of fly ash reduces internal friction, producing a mix that is easier to pump.
- Reduced segregation – Fly ash adds body to plastic-state concrete, increasing its cohesiveness.
- Less bleedwater – Fly ash's lower water content reduces bleeding.
Benefits to hardened concrete
- Increased strength – In concrete, fly ash will continue to react with available lime and alkali, causing it to gain strength beyond 28 days.
- Reduced drying shrinkage – Fly ash concrete requires less water, hence less volume lost in drying.
- Decreased permeability – Fly ash particles pack tightly. In addition, the chemical reaction between fly ash and lime forms bonds that block bleed channels and fill pore spaces.
- Resistance to sulfate attack – Fly ash combines with free lime, making it unavailable to react with sulfates that can cause expansion problems.
- Improved durability - Less free lime, greater strength and less permeability produce concrete that withstands more punishment over the long term.
- Reduced heat of hydration – Large concrete masses typically generate high internal temperatures and experience thermal cracking as a result. By replacing a portion of portland cement with fly ash, your concrete will generate less heat and thus be less prone to fractures.
- Mitigated alkali silica reaction 'ASR' – Fly ash reacts with available alkalis in the hardened cement matrix, making them less likely to react with the aggregate.
Fly Ash in Flowable fill
Flowable fill is an engineered, low strength fill material you can use for a variety of construction needs. It is self-leveling, self-compacting, non-settling and has characteristics that compete favorably with traditional materials such as compacted soil, soil-cement and concrete. Flowable fill has the benefits of being easy to apply, durable and less labor intensive than competing products. Because flowable fill is fast and easy to place, you can reduce construction time and its associated costs.
In addition to the above benefits, flowable fill:
- Eliminates excavation for underground backfill
- Allows for narrower trenches
- Can be excavated using conventional equipment
- Produces no voids during placement
- Allows for faster return of traffic loads
- Reduces settlement and rutting under loading
- Improves worker safety by permitting placement without entering trench
Class F fly ash is a key component of flowable fill, along with water, sand and portland cement. Its compressive strength can be designed to range from 50 to 1200 psi. Mixes in the 50 to 70 psi range have at least two to three times the bearing capacity of well-compacted earthen backfill material. Most high fly ash content mixes only require from three to five percent portland cement to develop 28-day compressive strength in the 50 to 150 psi range.
Applications
Delivered in a slurry form that resembles workable concrete, flowable fill can meet a wide variety of needs. Common applications include:
- Sewer and utility backfill
- Bridge abutment backfill
- Culvert and trench backfill
- Bedding for slabs and pipes
- Fill for embankments, bases and sub-bases
- Fill for abandoned storage tanks, shafts and tunnels
Fly Ash as a Soil amendment
Soil amendment is the chemical and/or mechanical modification of soil properties to improve its engineering performance. Properties most often modified are strength, plasticity, density and water content. Typically, construction companies use fly ash along with lime, cement or lime kiln dust to achieve the desired effect. Using amendments can save a construction project significant time and money.
Using fly ash as a soil amendment:
- Enhances soil strength properties
- Improves the control of shrink/swell properties of expansive soils
- Eliminates the need for expensive borrow materials
- Expedites construction by improving excessively wet or unstable sub-grade
- Improves sub-grade conditions allowing for reduced pavement thickness
- Reduces the need for expensive aggregates in pavement cross sections
Soil Amendment and Soil Strength
Use fly ash to improve soil's compressive and shearing strength. Fly ash can effectively improve sub-grades, base courses and backfill, reducing lateral earth pressures and improving slope stability on embankments.
Soil Amendment and Shrink Swell
Some soils undergo extensive volumetric changes when subjected to fluctuating moisture content. If not controlled, these volumetric changes can impose loads that cause movement to structures and lead to premature failure. Fly ash reduces the potential of a plastic soil to undergo volumetric expansion by bonding the soil grains, restricting or reducing soil particle movement.
Soil Amendment and Water Content
Soil must be compacted to the maximum practical density to achieve a firm base for overlying structures. Fly ash serves as a drying agent for soils that are too wet to achieve the required density. The drying effect of fly ash in wet soil occurs rapidly, allowing you to quickly proceed with construction activities. Fly ash also makes soil more resistant to water infiltration.
Before using fly ash a soil amendment, consider:
- The rate of hydration reaction upon exposure to water
- Soil moisture content at the time of compaction
- Fly ash's sulfur content (>10-% may cause soil expansion)
The use of fly ash in soil amendment may be subject to local environmental requirements pertaining to leaching and interaction with ground water which should be considered.
Fly Ash in Mine reclamation
Once a surface mine has been tapped out, the excavated area can pose numerous hazards to surrounding communities. Abandoned mines have been associated with acid run-offs that contaminate local waterways. Highwalls, dilapidated mine structures and open shafts are obvious safety hazards to children who might play in the area. Residents often use abandoned mines as trash dumps, which contributes to rural blight and depresses land values.
To mitigate these hazards, the U.S. Department of the Interior awards and funds mining interests that actively seek to restore excavated landscapes to near-original conditions.
According to the Surface Mining Control and Reclamation Act (SMCRA) of 1977, placing coal combustion by-products (CCPs) such as fly ash on a mine site as part of a comprehensive restoration program usually benefits both human health and the environment. Using CCPs can also improve a project's economics when used as a non-toxic fill in the excavated area prior to grading and final reclamation.
Use fly ash and other CCPs as:
- An alkaline seal or fill material to contain acid forming materials and prevent the formation of acid mine drainage.
- An agricultural supplement to create artificial soil on abandoned mine lands where native soils are not available.
- A flowable fill that seals and stabilizes abandoned underground mines to prevent subsidence and the production of acid mine drainage.
- A construction material for dams to create a compact and durable base.
- A non-toxic fill material for final pits within the spoil area to reduce reclamation costs.
By using fly ash and other CCPs in mine reclamation, you can:
- Improve the quality of water in local lakes and streams
- More rapidly re-establish wildlife populations and aquatic habitats
- Accelerate the return of grass lands, wildlife and water fowl
- Promote stable long-term land utilization
- Increase local land value
In addition to promoting environmental stewardship, proactive mine reclamation can help your company avoid future liabilities associated with acidic water discharges, erosion and sediment pollution, subsidence, and other environmental pollution-related hazards.
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: Waste Management
