DRILLING FOR THE USE OF ROAR EXPANSIVE CEMENT
It is important to know how ROAR expansive cement works. Its basic principle is the high pressure it exerts on the material. That expansion pressure must be well directed. The expansion pressure will be directed towards where it finds less resistance. That is why it is very important to drill taking into account the free face of the rock, since all the pressure of the cement will be oriented towards that place.
OPTION A – SHREDDING
In this case we are interested in making small pieces of rock so that it can be handled manually or with small machines.
In this case a square mesh is made. With a hole spacing of 8 to 10 times the drilling diameter.
The approximate consumption of this method is between 10 Kg/m3-25Kg/m3
(depending on the hardness of the rock).
OPTION B – DISASSEMBLY
In this case, it is interesting to break the maximum volume of stone with the minimum possible consumption.
In this case, you want to make stones as large as possible and as long as they can be loaded by a machine. Lines parallel to the free face will be drilled. With a distance between holes within the same drilling line between 5 to 8 times the drilling diameter and a separation between the lines 15 to 40 times the drilling diameter.
The approximate consumption of this method is between 1 Kg/m3-10 Kg/m3
(depending on the hardness of the rock)
In option A the distance K must be similar to the distance L
In option B the distance of K can be 2 to 80 times greater than the distance of L (Depending on the hardness of the stone)
AND WHEN THERE IS NO FREE FACE?
If there is no free face, you have to manage to do it. This is achieved by tilting the holes at angles between 60º to 45º. This is how the pressure of the ROAR expansive cement is directed upwards. In this case, the separation between the holes must be reduced by 30% to 50% in a normal drilling, increasing the consumption of this method between 15 and 35 Kg /m3. Whenever possible, small dismounts will be made to get a small free face and thus continue with the ordinary method.
It is also recommended to make vertical holes in the center of the V (Strain) to help expansion. These may not be loaded or partially loaded
GUIDANCE TABLE FOR DRILLING
|Element to break||Hole depth||Distance between holes||Linear distance between holes||Hole diameter||Kg / m3|
HOW TO PROTECT A STRUCTURE?
In some of the cases we have footings, columns or types of structures that we want to ensure are not damaged. For this, an unfilled security perforation line can be made close to the structure. This creates a zone of discontinuity of the stresses produced by the Roar expansive cement (This line must not be filled) which serves as a relaxation.
RECOMMENDED HOLE DEPTH
- The maximum depth of a hole is 9 meters
- The maximum recommended depth of a hole is 3 meters
- The minimum depth of a hole is 4 times the diameter of that hole.
- In reinforced concrete, drill from 90% to 95% of its depth. On cornices or overhangs, drill as deep as you want to remove. In slabs, drill 2/3 to ¾ the thickness of the stone.
- In soft stone, like marble, the depth of the hole is 100%, in medium or hard stone, like granite, the depth of the hole is 105%.
- The best working diameter is 38 mm.
- The holes must be drilled to allow a free face for the ROAR EXPANSIVE CEMENT to push through. For example, drilling at a 45º angle on a flat surface will push it up, but drilling straight down may not allow the pressure any outlet. To knock down a block without pushing out the surrounding walls, drill a cone-shaped design in the center and fill these holes first. The cone will pop up and create a free face.
- The layout of the hole depends on the tensile strength of what is being broken, and the size of the pieces that you want when it is being made. This can often be determined experimentally.
- The hole design also depends on how fast the results are needed. More holes in less distance will result in less breaking time and more small parts, but this is a lot more work and more ROAR EXPANSIVE CEMENT.
- Slabs are much easier to break than reinforced concrete or overhangs, and boreholes can be spaced farther apart, especially if breaking speed is not essential
- To calculate the amount of ROAR expansive cement to be used. You need to know the number of holes, the depth of the holes. With these data, calculate the linear meters that you are going to carry out and according to the drilling diameter, it can be calculated using the following formula:
- These are theoretical consumption data of Kg per linear meter but it must be taken into account that there are factors that can influence the actual consumption of ROAR expansive cement. Such as the wear of the drilling materials, the cracks and joints of the ground, the ambient temperature and above all the accuracy of the mixture with the water of the ROAR expansive cement.
|Diameter mm||V (dm3)||Density (Kg/dm3)||Consumption KG (in a linear meter)|