DURABILITY OF ULTRA-HIGH PERFORMANCE CONCRETE IN NH4NO3 SOLUTION

Abstract

The present study assessed the workability, compressive strength, density and NH₄NO₃ resistance of ultra-high performance concrete (UHPC) with different contents of rice husk ash (RHA), silica fume (SF) and ground granulated blast-furnace slag (GGBS). With the same water and superplasticizer content, workability and compressive strength of UHPC containing RHA are similar to those of UHPC containing SF. The density of UHPC containing RHA at the age of 7 days is slightly higher than that of UHPC containing SF. With increasing of hydration time (28 days), the refining effect of SF on the microstructure of UHPC is more significant than that of RHA. Therefore, the SF-modified mixture possesses a higher density compared to the RHA-modified one. The deterioration of UHPC containing RHA in the NH₄NO₃ solution is more severely than that of UHPC containing SF. The combination of GGBS and RHA or SF was found to improve the properties of UHPC.

Keywords: UHPC; rice husk ash; GGBS; silica fume; NH₄NO₃ resistance.

Received: August 24^th, 2016, revised: September 5^th, 2016, accepted: October 13^th, 2016