The Effect of Fly Ash to Underwater Self-Compacting Concrete
|關鍵字:||水中自充填混凝土;L型流度;濁度;pH值;underwater self-consolidating concrete;L-flow test;turbidity;pH|
This study focus on the effect of fly ash on the properties on underwater self-compacting concrete. The fly ash was added on weight basis, while all the other ingredients remain the same. The optimum amount of fly ash was determined based on the minimized effect of fly ash on performances on L-flow test, pH value, and turbidity. The specimens with and without fly ash were compared on compressive strength, volume stability, and durability. The volume stability includes plastic shrinkage, autogenous shrinkage, drying shrinkage, and creep. RCPT was used as durability index. The tests were designed to simulate various structures under different environmental conditions. The specimens were cast in air, tap water, and sea water and cured in air(RH=40%) and wet cure(RH=95%). The creep test was performed in air and in water. The results were analyzed and compared to determine the quality and durability of structures. It is found that the underwater self-consolidating concrete with or without fly ash has better performance than conventional concrete.The concrete with fly ash showed that 1. Due to the better workability of fly ash, the water cementitious can be reduced and thus an26% increase in compressive strength is achieved. 2. The autogenous shrinkage for specimens with fly ash was reduced by 13%, 3. Drying shrinkage was reduced by 24%, 4. The creep tested in air or water showed a decrease of 4-5%. As to RCPT, due to a long term pozzolanic reaction of fly ash, the cumulated current was reduced by 37% compared to control specimens.
|Appears in Collections:||Thesis|