MineCrete S³ is a combination of exclusive innovative technologies incorporating specialized concrete formulations and polypropylene fiber. Due to its mechanical properties superior to the conventional shotcrete with MineCrete you can reduce the current thickness of the shotcrete in half.
The Figure illustrates the best set up and possible failure locations in the tensile bond strength testing. MineCrete was poured onto rock subtrate (norite) by making use of a 5mm thick Perspex glass with a 35mm diameterhole. Removal of perspex glass leaves behind uniform MineCrete thickness and does not necessitate any overcoming process.
A steel dolly was glued normal to the MineCrete thickness and does not necessitate any overcoming process. A steel dolly was glued normal to the MineCrete surface with a strong epoxy, or resin that was commercially available. After the hardening of epoxy, the tensile bonding was measured by pulling the dolly away from the rock substrate. The loading of MineCrete was done by load crontrol method and the rate was the same as the one used in tensile strength testing that was 0,005kN/s.
The test continues until the MineCrete material was detached frm the rock substrate while load and displacement were recorded. (H. Yilmaz)
When shotcrete is used as an integral part of a mine's ground support system, it is important to know the strength properties of the in place shotcrete.
Besides conventional strength parameters, such as the shotcrete's flexural, compressive, or tensile strength, the adhesion or bond strength of the shotcrete to the host rock must also be known in order to adequateley determine the shotcrete's ability to support the immediate ground near the surface of the mine opening.
Consequently, the adhesion strength of the shotcrete is a necessary parameter for ground support design.
Two basic types of shotcrete failure modes.
A: Fallout of only shotcrete indicating poor adhesion;
B: Fallout of shotcrete and rock indicating zones of weak rock (after Malmgren & Svensson, 1999)