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Hot Bitumen Grouting

Hot Bitumen Grouting is the most commonly used form of hot melt grouting. It is used to cut off high magnitude, subterranean water inflows.

The principle behind hot bitumen grouting is simple - it is able to perform in high flow situations due to its inherent anti-washout nature. The hot bitumen grout is injected at temperatures approaching 210° Celsius. At this temperature, the grout has a viscosity only slightly greater than water at room temperature. Unlike even the most 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. Upon contact with the ever-replenishing heat sink of the passing inflow water, the hot bitumen quickly turns from its injected fluid state to a highly viscous, tenaciously sticky, elasto-plastic state and eventually, after enough hot bitumen is injected, the aperture through which the inflow passes becomes plugged.

The two most notable Hot Bitumen Grouting projects completed by Geo-Foundations - in West Virginia and Missouri - both involved the elimination of fresh water inflows into limestone quarries via karstic void networks. Karst limestone is characterized by its high incidence of solution cavities, which can, in extreme examples like the Missouri quarry, manifest themselves in cavernous voids that occur along the formations' bedding planes. At the Missouri quarry, where the inflow entered the quarry via two sets of voids, each at least 6 metres high at depths exceeding 80 metres and 100 metres respectively, a total inflow of greater than 2,205 L/sec was successfully eliminated after less than seven hours of hot bitumen injection.

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