Influences of the Ratios of High-Calcium Fly Ash to Low-Calcium Fly Ash on the Strength and Drying Shrinkage of Geopolymer Mortar

2014 ◽  
Vol 931-932 ◽  
pp. 416-420 ◽  
Author(s):  
Ridtirud Charoenchai ◽  
Prinya Chindaprasirt
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Setting Time ◽  
Drying Shrinkage ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Class C ◽  
Class F Fly Ash ◽  
By Products ◽  
Class F

New types of binders are being developed as an alternative to traditional cement. These alternatives are developed to have better properties and to be more environmentally friendly. Geopolymer is a novel binder that is produced from by-products such as fly ash, rich hushes ash and bio mass ash. In this experiment, fly ash, which was a by-product from electrical-generating power plants, was used during the synthesis of geopolymer. According to ASTM standard C168, fly ash is categorized into two types: class F and class C. This research focuses on the effects of using both types of fly ashes on mechanical properties of geopolymer. The experiment studies the changes on setting time, drying shrinkage and compressive strength of geopolymer mortar when 0, 25, 50, 75 and 100 percent of total weight of class F fly ash (LCF) is substituted with class C counterpart (HCF). The study used sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) as alkali activators. The samples were cured for 24 hours either at an ambient temperature of 25°C or at an elevated temperature of 60°C.The result showed that the setting time of pure LCF geopolymer mortar was 6 times longer than that of the pure HCF ones. In addition to setting time, the specimens with 25 percent of their total binders weight replaced by HCF appeared to have the highest strength. However, the increase in HCF also increased the drying shrinkage by 6 and 12times when the specimens were cured at25°C and at 60°C respectively

scholarly journals Influence of Particle Size Distribution of High Calcium Fly Ash on HVFA Mortar Properties

2018 ◽  
Vol 20 (2) ◽  
pp. 51
Author(s):  
Antoni . ◽  
Hendra Surya Wibawa ◽  
Djwantoro Hardjito
Keyword(s):  
Particle Size ◽  
Compressive Strength ◽  
Fly Ash ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Setting Time ◽  
High Volume ◽  
High Volume Fly Ash ◽  
High Calcium ◽  
High Calcium Fly Ash

This study evaluates the effect of particle size distribution (PSD) of high calcium fly ash on high volume fly ash (HVFA) mortar characteristics. Four PSD variations of high calcium fly ash used were: unclassified fly ash and fly ash passing sieve No. 200, No. 325 and No. 400, respectively. The fly ash replacement ratio of the cementitious material ranged between 50-70%. The results show that with smaller fly ash particles size and higher levels of fly ash replacement, the workability of the mixture was increased with longer setting time. There was an increase in mortar compressive strength with finer fly ash particle size, compared to those with unclassified ones, with the highest strength was found at those with fly ash passing mesh No. 325. The increase was found due to better compactability of the mixture. Higher fly ash replacement reduced the mortar’s compressive strength, however, the rate was reduced when finer fly ash particles was used.

scholarly journals Drying shrinkage, strength and microstructure of alkali-activated high-calcium fly ash using FGD-gypsum and dolomite as expansive additive

2020 ◽  
Vol 114 ◽  
pp. 103760 ◽  
Author(s):  
Sakonwan Hanjitsuwan ◽  
Borwonrak Injorhor ◽  
Tanakorn Phoo-ngernkham ◽  
Nattapong Damrongwiriyanupap ◽  
Long-Yuan Li ◽  
...  
Keyword(s):  
Fly Ash ◽  
Drying Shrinkage ◽  
Fgd Gypsum ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Expansive Additive ◽  
Alkali Activated

scholarly journals Enhancement the Performance of Asphalt Pavement Using Fly Ash Wastes in Saudi Arabia

2018 ◽  
Vol 7 (3.32) ◽  
pp. 50
Author(s):  
Mohammed Dahim ◽  
. .
Keyword(s):  
Saudi Arabia ◽  
Fly Ash ◽  
Rheological Properties ◽  
Asphalt Pavement ◽  
Toxic Substance ◽  
Arab Country ◽  
Toxic Waste ◽  
Class C ◽  
Class F Fly Ash ◽  
Class F

Saudi Arabia is the largest Arab country and is one of the most prolific producers of oil and energy consumption. The Kingdom uses heavy oil and diesel to generate electricity and desalinate seawater. This produces large amounts of ash, a toxic substance that is disposed of by landfill and may cause many environmental problems and contribute to pollution of groundwater, which is one of the most important sources of drinking water. This paper presents the possibility of using fly ash by-product waste from electric power generation plants to improve the properties of asphalt mixtures. This study investigates the use of two types of fly ash namely; class C and class F was used as a filler in two types of bitumen and asphalt material known as AC 40/50 and AC 60/70. The rheological performance of asphalt with different percentages of fly ash filler ranging from 0% to 10% with an increment of 2% was tested. The rheological properties of both asphalts modified using both types of ash were determined. The rutting factors of the modified asphalt with fly ash content were calculated using the rheological properties. The result indicates that rutting resistance of asphalt could be improved by both types of fly ash which can be lead to reduces the costs of repairing and rehabilitation of asphalt pavement and reduce environmental impacts of a significant amount of toxic waste fly ash. Class F fly ash shows higher rutting factor than class C. Also AC 60/70 asphalt possess higher rutting factor than AC 40/50 asphalt at both low and high temperature.  

Engineering Properties of Loess-Fly Ash Mixtures for Roadbase Construction

2000 ◽  
Vol 1714 (1) ◽  
pp. 49-56 ◽  
Author(s):  
Nayyar Zia ◽  
Patrick J. Fox
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Loess Soil ◽  
Engineering Properties ◽  
Simple Method ◽  
Testing Program ◽  
Loess Soils ◽  
High Calcium ◽  
Swell Potential ◽  
Class C

Southwest Indiana has large deposits of wind-blown loess. Similar deposits are found in other states, including Illinois, Kentucky, Iowa, Minnesota, Missouri, and Nebraska. These soils consist of uniform silt with a plasticity index ranging from 0 to 10. This material is suitable for road construction if it is compacted dry of optimum. However, the material is difficult to work after it becomes wet, which commonly results in construction delays. Indiana also has large stockpiles of Class C fly ash from coal-burning power plants. The ash has cementitious properties after hydration (because of the high calcium content) and can be mixed with native soil to produce a weakly cemented soil. Significant interest exists at the Indiana Department of Transportation about the possibility of using Class C fly ash to improve the engineering properties of Indiana loess soils. The results of a laboratory testing program on the properties of loess–fly ash mixtures are presented. Various percentages of fly ash were mixed with loess soil and specimens were permitted to cure for 3 h to 28 days. Pure loess also was tested for comparison. Changes in Atterberg limits, moisture-density relationships, swell potential, and unconfined compression strength are presented. Based on this testing program, a simple method was developed to determine the optimum fly ash content for construction of a workable loess roadbed to avoid delays in construction due to wet conditions. The data presented will be useful for evaluating the stabilization of loess soils with Class C fly ash in Indiana and other states with significant loess soil deposits.

Setting Time, Strength, and Bond of High-Calcium Fly Ash Geopolymer Concrete

2015 ◽  
Vol 27 (7) ◽  
pp. 04014198 ◽  
Author(s):  
Pattanapong Topark-Ngarm ◽  
Prinya Chindaprasirt ◽  
Vanchai Sata
Keyword(s):  
Fly Ash ◽  
Setting Time ◽  
Geopolymer Concrete ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Time Strength
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