Hot Bitumen Grouting is a special type of grouting where melted bitumen is used as grouting material. Hot-Bitumen grouting is often used to cut off high magnitude, subterranean water inflows.
The major feature of hot bitumen grout is its temperature dependent viscosity. The bitumen is first preheated up to approximately 200° Celsius. At this temperature, the grout has a dynamic viscosity in the range of 15 to 100 cp, which is only slightly greater than water at room temperature. Unlike the least viscous chemical resin grouts or the stiffest cement-based mortar grouts, which each have curing processes that are time-dependent, hot bitumen's curing is thermally driven. When hot bitumen is injected into medium saturated with water, it cools quickly at the interface, and turns from its fluid state to a highly viscous, tenaciously sticky, elasto-plastic state. Eventually, after enough hot bitumen is injected, the aperture through which the inflow passes becomes plugged.
Hot bitumen grout is often used in conjunction with cement based suspension grout, in order to reduce grout spread, to make bitumen less creep susceptible, and to increase the mechanical strength of the end product.
There are many types of bitumen with wide range of characteristics, but the desirable type for use in grouting, is a “hard” oxidized environmentally friendly type of bitumen with a high solidification point.