STUDY ON THE EFFECT OF COMBUSTION TEMPERATURE ON VIETNAM RICE HUSK AND CONCRETE MADE WITH VIETNAM RICE HUSK ASH
| Autor: | Bui Le Anh Tuan, 裴黎英俊 |
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| Rok vydání: | 2010 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 98 In this study, rice husk ash (RHA) prepared from the waste RHA from an electric furnace in Vietnam and RHA produced at different combustion temperatures (from 300 to 1000℃) from Vietnam rice husk were made and compared. The properties of these ashes were determined. ACI mix design and Hwang Fuller’s Densified Mixture Design Algorithm (HFDMDA) were used to calculate the mix proportions for normal and high performance concrete, respectively. The effect of RHA average particle size and the influence of chemical activators K2SO4 were studied on high performance concrete. Three different coating paste thickness, 5µm, 15 µm, 25 µm and three different water-to-binder material ratios (0.23, 0,35 and 0.47), were used. The possibility of rice husk ash utilization in concrete was emphasized on normal concrete. For the normal concrete, three different replacement percentages of cement by RHA, 10%, 20% and 30%, and three different water-to- binder material ratios (0.23, 0,35 and 0.47), were used. The properties of concrete were investigated at fresh and harden stages. Test results showed that to produce useful rice husk ash, the rice husk should be burnt beyond 500℃. RHA will change from amorphous forms to crystalline form of silica at 800℃. Incorporation of RHA in concrete resulted in increased water demand. Addition of unground ashes was related to a decrease in compressive strength. Increasing RHA fineness would enhance the strength and durability of blended concrete. The drying shrinkage was significantly affected by RHA fineness; ground recorded the higher shrinkage value. Test results showed that up to 20% replacement of cement with ground RHA improves the compressive strength and durability properties of concrete. Using chemical activator did not receive good improvement on the properties of concrete. HFDMDA method used less cement and water than ACI method. At the same strength, HFDMDA proportioning method for concrete can saves the consumption of cement and a significant reduction of energy, CO2 emission. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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