A Preliminary Research on Alkali-Activated Slag Concrete as Tunnel Lining in Severe Frigid Regions

Abstract

The main structure materials of tunnel lining are concrete and steel, and the concrete frost damage is a typical degradation phenomenon of the tunnel linings in cold regions. Alkali-activated slag concrete (ASC) has a better freeze-thaw resistance, which can be used for tunnel lining in severe frigid regions. Freeze-thaw resistance, performance mechanism of ASC and microstructure were investigated by freeze-thaw cycle, X-ray diffraction (XRD) and Scanning electron microscope (SEM) analysis. The experimental results show that, ASC has excellent freeze-thaw resistance, and hydration products of ASC are mostly C-S-H, alkaline aluminosilicate. ASC has a good compact degree and uniformity of structure, and its high compressive strength also makes high freeze-thaw resistance. ASC may be selected as tunnel lining production materials in severe frigid regions because of the less reduction in the dynamic elastic modulus and mass loss of concrete.

A Review on the Durability of Alkali-Activated Fly Ash/Slag Systems: Advances, Issues, and Perspectives

“…Similar conclusions have been reported for fly ash mortars, in comparison to OPC-based specimens. 79 Shu 80 reported that AAS concrete showed excellent freeze− thaw resistance, thus fitting their application in tunnel lining in extremely cold regions. It was also shown that, using a blend of fly ash and slag in concrete synthesis, the relative dynamic modulus was ∼90% after 300 freeze−thaw cycles with a slight mass loss and physical deterioration due to thin surface layers that favorably restrain freeze−thaw damage of concrete.…”

Freeze-Thaw and Fire Resistance of Geopolymer Mortar Based on Natural and Waste Pozzolans

“…It was also found that air-entraining admixtures commonly used to increase the freeze-thaw durability of Portland cement concrete did not increase the durability of alkali activated fly ash materials. Heng [21] reported that alkali activated slag concrete showed excellent freeze-thaw resistance, thus fitting their application in tunnel lining in extremely cold regions.…”