Mechanical Properties of Fly Ash Mixed with Furnace Slag-coal Gangue

Abstract

【Objective】 Fly ashes mixed with furnace slag-coal gangue have been increasingly used as a building material in Ningxia province of China. This paper analyzes the change in its mechanical properties at different mixing ratios. 【Method】 Fly ashes were mixed with cement at ratio of 3%, 4%, 5% and 6%, and with slag-coal gangue at 0%, 25%, 50%, 75% and 100%, respectively. The mechanical properties of each specimen were measured using triaxial test and ultrasonic test, from which we established the relationship between the unconfined compressive strength and the splitting strength for all treatments. 【Result】 The damage pattern of the specimens in the triaxial test was mediated by the surrounding pressure, showing a typical shear failure. The strength of all specimens can be estimated using slag content, cement content and the surrounding pressure. The scanning electron microscopy showed that the main hydration products of the specimens were C-S-H and Aft. The ultrasonic test revealed that the unconfined compressive strength of the specimens was positively correlated to the amplitude. 【Conclusion】 After reinforcing the fly ash with slag-coal gangue at appropriate ratio, it can be used as a building materials for dam and pavement construction.

Keywords

• damage morphology
• mechanical properties
• fly ash
• furnace slag-coal gangue
• triaxial test
• micromechanism