Durability study on concrete made with incinerator ash and CaF2 sludge slags
Date Issued
2005
Date
2005
Author(s)
Lin, Shih-Wei
DOI
zh-TW
Abstract
The purpose of this research was to study the effects of co-melting slags produced from municipal solid waste incinerator bottom ash and industrial calcium fluoride sludge on pozzolanic reaction and durability in cement-based composites materials. The co-melting slag was water-quenched with room temperature. Experiments were conducted to (1) determine the lowest pouring temperature of co-melting ash and sludge at different proportions. (2) analyze the physical and chemical characteristics of the pulverized slag, such as specific gravity, particle size, chemical composition, TCLP, XRD patterns and strength activity index (SAI). (3) incorporate the slag as mineral admixtures in the cement-based composites materials in place of a fraction of the cement, and evaluate the influence of the replacement ratio on performance of the cement-based composites materials in terms of setting times, compressive strengths, electrical resisitivity, the rapid chloride penetration test (RCPT) , etc.
The results showed that the lowest pouring temperature was 1081℃ when the co-melting ash and sludge were in the ratio of 7:3. The molten slag was then water-cooled and examined its properties. It was observed that the water-quenched slag was amorphous and had a specific gravity of 3.15 which was close to Class C fly ash.
The results of compressive strength, degree of hydration, MIP and SEM indicated that the slag was a latent pozzolans and it could replace 3% to 20% cement in mortar. It was also observed that 3% replacement of cement with slag would enhance concrete properties with denser microstructure based on pulse velocity, resisitivity and RCPT results. Furthermore, resisitivity test results showed that the influence of curing time on concrete durability is more important than that of cement replacement on concrete duability. The relationship between cement replacement and cumulative charges from RCPT results shows that there existed a critical point which could be employed as the indicator for choosing a suitable replacement ratio. In addition, the aluminate phase of the slag could bind chlorides to form Fredel’s salt resulting from reinforced concrete corrosion test. It implied that blending cement with slag would decrease the diffusivity of chloride in the concrete and improve its durability.
Subjects
熔融
摻料
卜作嵐性質
耐久性
佛萊第鹽類
melting
admixtures
pozzolanic reaction
durability
Friedel’s salts
Type
thesis