Application of Nano Silica in Concrete for Enhanced Resistance against Sulfate Attack

摘要

Durability of concrete structure is a critical issue especially in severe environment when the concrete structure is exposed to sulfate attack, such as shorelines. Nano Silica is high pozzolank-material which is used recently in concrete to improve its mechanical properties. However, the durability of concrete against sulfate attack containing Nano Silica (NS) has not been investigated completely. In this study, the effects of NS has been studied on compressive strength, sulfate attack and morphology characteristics. The results show that increasing of compressive strength in specimens with NS is significant in early ages. Resistance of concrete specimen against sulfate attack was measured in 5% sodium sulfate solution for expansion of prime specimens. After a period of 180Days the samples containing zero, 2,4, 6 and 8% NS lost 3.51%, 2.4%, 2.23%, 1.13% and 1% of their weights compared to the initial weights, respectively. The results indicate that the concrete samples containing 8% NS show best performance in terms of resistance against sulfate attack.