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Fly Ash Sustainability
Name: Fly Ash Sustainability
File: minkara presentation 05-13-15 4B.pdf
Size(MB): 2.65MB
Extension: PDF
Event: 2015 ICSC - MIAMI
Speaker Name: Minkara, R.
Managed by: sdickens
Date Uploaded: May 29, 2015; 3:02 pm
Download Count: 563
Downloads This Month: 563

Your Geographic Information:

Country: United States
State/Region: Texas
City: Houston
Zip Code: 77072
Area Code: 281
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"Fly ash plays a vital role in the sustainability of concrete. It increases the strength and improves the durability of concrete by forming additional cementing binders, resulting in a denser matrix and making concrete less susceptible to degradation by aggressive agents such as chlorides and sulfates. Fly ash use in concrete has significantly increased over the last few decades due primarily to industry initiatives. These initiatives include marketing and outreach, investments in logistics, as well as research and development to demonstrate the benefits of using fly ash and to address quality concerns resulting from coal-fired power plant operational changes.
Concrete is essentially a sustainable building material. Its basic ingredients are abundantly available and its life cycle assessment compares favorably to competing materials such as asphalt, steel and wood. The sustainability of concrete is further enhanced by using recovered industrial material, such as fly ash, to substitute for a portion of portland cement thereby reducing the environmental footprint of concrete and improving its life cycle performance. The beneficial use of fly ash as construction materials provides substantial environmental, commercial and economic benefits.
There are concerns in the concrete industry about the long-term sustainability of fly ash for use in concrete. One of the perceived concerns is the quality degradation resulting from sorbent injection at power plants for air emission control. For example, activated carbon injection is being used to reduce mercury emissions. The activated carbon, when collected with the fly ash and used in concrete, would interfere with the air entraining agents ability to generate and maintain air voids.
The RestoreAir® technology developed by Headwaters has been effectively deployed to treat fly ash at the power plant prior to delivery to customers. The technology uses a low dosage of liquid reagent to passivate the carbon surfaces and reduce their ability to adsorb air entraining agents in concrete. Carbon is not removed, but its effect on air entrainment is neutralized. The technology also includes a novel sensor that determines the chemisorption characteristic of activated carbon/ash at very low activated carbon concentrations. Unlike the traditional foam index test, this new diagnostic test is not subjective and can be automated to provide real-time on-line measurements of ash activity."

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