Development of Engineering Properties of Paste and Mortar with Fly Ash Substitution and Addition of Alkaline Activator

• Main Authors: Vina Setiawan, 藍慧妃
• Other Authors: Ta-Peng Chang
• Format: Others
• Language: en_US
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/n94rs4

碩士 === 國立臺灣科技大學 === 營建工程系 === 106 === This study investigated the engineering properties development of hardened paste and mortar using class F fly ash to partially replace cement and addition of sodium silicate to partially replace mixing water. Experimental variables included three different water-binder ratios (0.3, 0.4, 0.5), four different fly ash substitutions (0%, 10%, 30%, and 50%), and three different amount of sodium silicate (0%, 5%, and 10%) were observed. The fresh properties including workability, setting time, and pH value, then the hardened properties including compressive strength, drying shrinkage, ultrasonic pulse velocity (UPV), dynamic Young’s modulus, dynamic shear modulus, and dynamic Poisson’s ratio were examined through in this study. The results showed that the application of fly ash improved the engineering properties of paste and mortar for the fly ash substitution up to 30%. At the early age, the strength decreased with the increase of fly ash substitutions due to the low hydration rate using the fly ash. However, the strengths of all the paste and mortar specimens increased by about 20% using the fly ash replacement up to 30% compared with that of the control set at the age of 56 days. The application of sodium silicate did not affect the engineering properties. On the contrary, it reduced the engineering properties. It can be concluded that the presence of sodium silicate did not activate the pozzolanic reaction of fly ash as expected.