Thermal power stations use pulverized coal as fuel. They produce enormous quantities of coal ash as a by-product of combustion. This calls for the development of strategies to encourage and establish technological concepts which will ensure consumption of fly ash in bulk. Among the various uses of fly ash, its bulk utilization is possible only in geotechnical engineering applications. This necessitates characterization of the fly ash with reference to geotechnical applications. This paper presents a review of such studies carried out. The results show that fly ash is a freely draining material with angle of internal friction of more than 30 degrees. The specific gravity is lower leading to lower unit weights resulting in lower earth pressures. It can be summarized that fly ash (with some modifications/additives, if required) can be effectively utilized in geotechnical applications.

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Fly ash characterization with reference to geotechnical applications

This paper presents the shear strength characteristics of a low lime class F fly ash modified with lime alone or in combination with gypsum. Unconfined compression tests were conducted for both unsoaked and soaked specimens cured up to 90 days. Addition of a small percentage of gypsum (0.5 and 1.0%) along with lime (4–10%) enhanced the shear strength of modified fly ash within short curing periods (7 and 28 days). The gain in unsoaked unconfined compressive strength ( qu ) of the fly ash was 2,853 and 3,567% at 28 and 90 days curing, respectively, for addition of 10% lime along with 1% gypsum to the fly ash. The effect of 24 h soaking showed reduction of qu varying from 30 to 2% depending on mix proportions and curing period. Unconsolidated undrained triaxial tests with pore-pressure measurements were conducted for 7 and 28 days cured specimens. The cohesion of the Class F fly ash increased up to 3,150% with addition of 10% lime along with 1% gypsum to the fly ash and cured for 28 days. The modified fly a...

Strength Characteristics of Class F Fly Ash Modified with Lime and Gypsum

Impacts of pH on leaching potential of elements from MSW incineration fly ash

Mechanical behavior of mortars containing sewage sludge ash (SSA) and Portland cements with different tricalcium aluminate content

Performance evaluation of cement stabilized fly ash–GBFS mixes as a highway construction material

Since the late 1950s solid waste incinerators have become widely used in the United States. The incineration of solid waste produces large quantities of bottom and fly ash, which has been disposed of primarily by landfilling. However, as landfills become undesirable other disposal methods are being sought. An experimental research program is conducted to determine engineering properties of solid waste incinerator fly ash (SWIF) in order to evaluate the feasibility of using the material for compacted fill and road and subbase construction. Moisture‐density relationship, permeability, shear strength, and California bearing ratio (CBR) are investigated. The effects of densification on these engineering properties are also examined. In addition, the effectiveness of cement and lime stabilization is investigated using two common mix ratios. Test results of stabilized mixes are compared to the unstabilized material. Cement stabilization is found to be very effective in reducing permeability, and increasing shea...

Chaim J. Poran

Papers

Properties of solid waste incinerator fly ash