# Blasting technology

The blasting is a branch of engineering, physics and mathematics. It deals with explosions and their explosive forces, directions, explosive substances, areas of application for explosives and explosive housings.

A distinction is made between the sub-areas

• Swelling or press blasting
• Explosive explosions

## Spring blasting

A homogeneous substance can be separated by the action of directed forces along a defined dividing line. This very old technique was used as early as the Neolithic . For this purpose z. B. in a quarry along the dividing line for a stone cuboid holes are drilled, the depth of which determines the height of the cuboid. Then some or all of the holes are filled with a swellable material (e.g. wood, hemp). If you add water to the swelling substance, it sucks up the water and expands. The resulting forces act equally in all directions. The distance to the next free area (next empty hole or outer wall) is the path of least resistance. The structure of the material tears open along this line and hairline cracks and even crevices develop. Since they do not contain any explosive substances, they are not subject to the law on explosives.

## Explosive explosions

The use of explosives changes or destroys the material structure of the substance to be exploded. This effect is essentially based on three factors:

• pressure
• temperature
• speed

The increase in pressure per unit of time is also known as the detonation pulse. Such a very short and extremely violent blow is capable of changing or tearing material structures (e.g. lattice structures in metals). The temperature development, on the other hand, plays a subordinate role in most blasting processes, but also contributes to the result of the blasting. Typical values ​​for detonation pressures are in the range of several thousand bar , the detonation speeds reach up to 10,000 m / s. The explosive object is microstructurally shattered by the detonation pulse. The subsequent gas pressure of the so-called explosive fumes "blows" the fragments out of the explosive zone. Other uses of detonating substances have also been documented. So z. B. non-weldable materials are inseparably connected to each other by explosion welding . Embossing impressions are also permanently reproduced by explosive plating . The most important applications, however, are the extraction of raw materials ( ore , coal , salt , stone ), the construction of tunnels and roads, and the dismantling of buildings. Dealing with explosive substances - i.e. explosives and detonating agents or objects that contain them - is only permitted in Germany with an officially issued qualification in accordance with Section 20 or Section 27 of the Explosives Act .

## literature

• Dietrich Korth "Use of blasting technology in traffic route construction through moorland areas, TIEFBAU 1/2007, pp. 21–26, knowledge portal of the TU Dresden (www.baumaschine.de/Portal/Tbg/2007/heft1/a021_026.pdf).
• SJ von Romocki: History of Explosives. Volume 1. History of explosives chemistry, blasting technology and torpedo use up to the beginning of the modern era, with an introduction by Max Jähns . Survival Press, (Berlin and) Radolfzell 1895, reprints Hildesheim 1976 and 1983, reprint 2003, ISBN 3-8330-0702-8 .