Highway pavements are an essential component of the transportation system providing access and establishing linkages between one corner to another throughout the world. Due to its utmost(greatest) importance, there has been a need to construct highways that are structurally sound as well as facilitate the easy and comfortable movement of goods and people. The stability and quality of roads are thus checked by carrying out several tests. Among the tests; Dynamic Cone Penetration Test is one.
The Dynamic Cone Penetration Test is a type of test that is carried out to check the structural properties of existing pavements. It was developed by Transport and Road Research Laboratory in England.
It is also called as DCP Test.
Apparatus Required :
The dynamic cone penetration test apparatus consists of a steel rod with a 60degree conical tip. The rod is further topped by an anvil which is further connected to a steel rod. This rod acts as a guide for the hammer to be raised and dropped from a height of about 575 mm.
The procedure of Dynamic Cone Penetration Test (DCP Test):
1. The test apparatus is first assembled. After assembling, the initial reading( zero reading) of apparatus is recorded. This is done by standing the apparatus on a hard surface such as concrete, checking that it is vertical and then entering zero.
2. The instrument is then held vertically and the weight is carefully raised to the handle. It must be ensured that the weight is touching the handle.
3. The readings are then noted at an increment of penetration of about 10mm. This step is carried out by dropping the weight.
4. After completion of the DCP test, the penetrometer is gently removed by tapping gently the weight upwards against the handle.
Correlations to Engineering Parameters
log(DPI) = -1.05 + 2.03 * log(SPT)
- CBR = California Bearing Ratio
- DPI = DCP Penetration Index
- SPT = Standard Penetration Test (ASTM D 1586-64)
Precautions in DCP Test
a. Proper handling of the instrument.
b. Reading must be taken carefully.
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