SODIUM POLYPHOSPHATE-MODIFIED CLASS C/CLASS F FLY ASH BLEND CEMENTS FOR GEOTHERMAL WELLS.

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.

Download Full-text

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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.931-932.416 ◽

2014 ◽

Vol 931-932 ◽

pp. 416-420 ◽

Cited By ~ 1

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

Download Full-text