Concrete Lining Fire Resistance in High Temperature Tunnels: Experimental Study

This paper presents an experimental study examining the fire resistance of concrete lining in high-temperature tunnels. The research was conducted to address the growing concern over tunnel fires, which have caused significant infrastructure damage and loss of life. The primary objective was to evaluate the structural integrity of concrete lining when exposed to extreme heat.

The experiment involved a 1.8-meter-long, 0.6-meter-diameter tunnel model constructed with concrete. Two heating systems were employed to simulate fire conditions. The initial fire stage was simulated using a gas burner that delivered a heat flux of 200 kW/m2, while the extreme fire conditions were mimicked with a propane burner emitting 800 kW/m2.

Results showed that the concrete lining successfully withstood the initial fire conditions. However, when the heat flux was raised to 800 kW/m2, the concrete lining's temperature escalated rapidly, and cracks began to form after 30 minutes of exposure. The concrete continued to deteriorate, leading to collapse after 90 minutes of exposure.

The study also explored the impact of steel fibers on the fire resistance of concrete lining. It was found that the addition of steel fibers improved the concrete's ability to withstand extreme fire conditions for a longer duration compared to plain concrete.

This study emphasizes the crucial role of fire resistance in tunnel design and construction. The incorporation of steel fibers in concrete mixtures has the potential to enhance the fire resistance of tunnel lining, reducing the risk of collapse during tunnel fires.

Reference:

Jiang, H., Li, Q., & Liu, Y. (2018). Experimental study on the fire resistance of concrete lining in high-temperature tunnels. Fire technology, 54(6), 1751-1766.