Use of explosives in civil engineering

The operation of an explosive product is a chemical reaction triggered by an "ignition", which depends on the conditions in which it occurs. An important part of the implementation work consists in adapting the products (and their operating limits) to the anticipated conditions of use: choice of initiation, determination of a sufficient quantity of explosive energy, definition of the nature and condition of the materials. Whether in demolition or rock removal, the success of a blast (in terms of efficiency and safety) is linked to the interaction of the "explosive products-materials" pair.

The term "explosives" covers all priming products and devices. An explosive is a substance or mixture of substances which decomposes, resulting in the sudden release of a large quantity of energy over a very short period of time. The mode of decomposition depends not only on the nature of the product, but also on the nature and strength of the reaction initiator. A product can have several modes of decomposition (combustion, deflagration, detonation) and, under certain conditions, can switch from one mode to another.

Detonation is the fastest decomposition regime: it generates a very high temperature, a shock wave and the release of a large volume of gas, i.e. the most significant mechanical effects on the surrounding environment. The total energy of the explosive, the shock energy and gas energy released, and the detonation velocity are therefore theoretical parameters characteristic of different explosives. Their variations are the distinguishing features of explosive product ranges.