Abstract

Microsilica-gel bonded no-cement refractory castables (NCCs) have lately drawn great attention, not only because of their easier handling, storage and transportation thanks to the “all-in-the-bag” solution, but also because of the improved setting behaviour and green strength development compared to silica-sol bonded NCCs.

The current work addresses the development of no-cement shotcrete using microsilica powder as a binder. The flow, setting-behaviour, mechanical properties, hot-properties and abrasion resistance of no-cement shotcrete were compared to low-cement shotcrete. The results demonstrate that the cement-free shotcrete not only exhibits good installation properties and low rebound, but also provides enhanced hot-properties and abrasion resistance due to mullite formation at elevated temperatures.

Furthermore, a laboratory program on the effect of a speciality-drying agent on explosion and thermal-shock resistance on the shotcrete NCC composition showed that both the explosion- and thermal-shock resistance were significantly improved compared to the shotcrete LCC composition.