CRACKAMITE is a Non-Explosive Silent Cracking/Demolition Agent
which works by providing silent expansive cracking.

Most effective solution for Rock Breaking, Stone Quarrying,
Mining, Concreate Demolition, Excavations and More...

How Does Crackamite Work?

When Crackamite is mixed with an appropriate quantity of water and poured into cylindrical holes drilled in rock or concrete, it hardens and creates an amazing expansive pressure of 11 MT/m2. Crackamite cracks the matter to be demolished which then can be easily removed with a pick breaker, pneumatic breaker, excavator, etc.

Crackamite develops a very high expansive capability at a consistent volume exceeding 122 Mpa (11,200 T/m2) more than enough to break up any materials to be cut or demolished. The tensile strength for most rock is less than 5 - 25 Mpa (500 - 2500 T/m2  50 - 250 kg/cm2) while reinforced concrete breaks at 3 - 5 Mp (30 - 50 kg/cm2, 300 - 500 T/m2).

Fracture Mechanism of Crackamite

After Crackamite is poured into holes drilled in rocks or concrete, the expansive stress gradually increases with time, and reaches to more than 11,000 T/m2 at room temperature after 24 hours. As Crackamite generates its expansive stress, the material to be cracked undergoes a process of (1) crack initiation, (2) crack propagation, (3) the increase of crack width. Therefore, this fracture mechanism is distinguished from a breakage by blasting.

The mechanism by the expansive stress of Crackamite is shown in Fig. 1. Cracks initiate from an inner surface of the hole, being caused by tensile stress at a right angle with the compressive stress that occurs by the expansive stress of Crackamite. The expansive stress of Crackamite continues even after the appearance of cracks, the cracks propagate and also new cracks initiate during the process. Usually, for a single hole, 2 - 4 cracks initiate and propagate. When a free surface exists, the crack, as shown in Fig. 2, is pushed apart mainly by the shear stress, and a secondary crack also arises from the bottom of the hole running toward the free surface.


Fig. 1 - Fracture mechanism by the expansive stress of
Crackamite


Fig.
2 - Sectional-view of the crack formation in the material with two free surfaces

When multiple numbers of holes are filled with Crackamite, that are properly adjacent to each other, the cracks from the hole propagate to connect with the neighboring holes, as shown in Fig. 3. It is therefore possible to determine the directions of the cracks as planned by appropriately arranging the hole spacing and its depth and its inclination.


Fig.
3 - Crack propagation

Establishment of free surface:

In the case of trenching, shafting or tunneling, if all holes are drilled vertically and filled with Crackamite, the crack width cannot increase but horizontal cracks initiate. Therefore, in order to obtain two free surfaces, inclined holes or pre-splitting must be required.

Split Slab