To determine the unconfined compressive strength of rocks in UTM machine.
EQUIPMENTS: UTM according to specifications listed in the ASTM code C-170, cleaning cloth, Vernier caliper with the accuracy of 0.1mm to measure the length and dia of core samples or scale.
SPECIMEN:Locally available rock cores free from discontinuities, cracks, fractures should be of regular sizes.
THEORY
Compressive Strength: Compressive Strength is the capacity of any rock to withstand the loads, which tends to reduce size. In other words, compressive strength resists being pushed together. Compressive strength is internal behavior of rocks to external loads. When loads are applied on them from outer side stress will produce inside the rocks which resist to being fracture. When the rocks crosses the limit of compressive strength it gets fractured. Compressive strength of rock is measured in UTM machine as shown in figure
PROCEDURE
- Choose the sample and standardize it.
- To find out the dimension (length, dia, height) by Vernier caliper.
- To clean the surface.
- Calculate the cross section area of core by formula 2 .where r = .
- Place the sample vertically in the UTM.
- Note the initial load.
- Also, note the final load where the sample breaks.
SAMPLES:
OBSERVATIONS
Rock Name:__________________________
| Specimen No. | Initial load(N) | Final load(N) | Applied load(N) |
Now the load can be calculated as load = final load – initial load
Compressive strength of rock =
Results:
Comments: