What is the CBR test procedure on site

What is the CBR test procedure on site and how does the process work?

 

What is the definition of CBR?

The process of CBR testing can sound complicated for some people to understand but here is a simpler explanation. CBR is the ratio of the force required per unit area that is needed to penetrate the soil mass. It is with the standard circular piston at the rate of 1.25mm/min. Developed by the California State Highway Department (USA)before the second world war the California Bearing Ratio Test is a test that evaluates the bearing capacity of subgrade soil. The test is carried out on natural lands in or out of water conditions. The test results are then compared with the standard test curves.It was developed to measure the load bearing strength when building roads. This test is significant during construction.

It is done to get an idea of how the heavy the subgrade soil is. Some of the tools used in the process include.

  • Mould
  • A working and reliable Steel Cutting collar
  • Spacer Disc
  • Good quality Dail gauges
  • Surcharge weight
  • An active penetration Plunger
  • IS Sieves
  • A proper working Loading Machine
  • And other Miscellaneous Apparatus.

These are just some of the apparatus that may be needed. However, the test will determine the tools being used depending on how extensive it will be and the size of the site.The process can be done by professional especially for massive projects.

The process of CBR testing on site.

Three specimens of about 7kg are compacted to range the density from 95% to 100%.

The negative Mould has to be weighed. Add some water into the first specimen and compact into five layers this is by giving ten blows per layer. After this is done remove the collar, then go ahead and level the surface.It is no time to take a sample of the moisture content then weigh the Mould and the compacted specimen.If it is a soaked CBR, you can soak the tank for a few days. Then you should take the bowls and apply different samples then repeat the process. Ater waiting for atleast for days measure the swell reading. Go ahead and drain the water by removing the Mould for the tank.

 

Subcharge a load of 10lb after placing the specimen under the penetration piston. This is the time to apply and take notes on the penetration values. Then it is time to draw a graph between the penetration and penetration load. This is how you find the value of the CBR. A chart between the percentage CBR and Dry density will help you find the CBR at the compaction degree.

 

What is the importance of the CBR test?

 

It is one of the most common ways of evaluating sub grade soil strength. Also the sub base, base course material and determining the thickness of the highway designs and also the width of the airfield pavements.It will determine how flexible the pavement can get.

 

The more the CBR, the stronger the soil. The density could be less, and so the CBR will be very minimal.

What is the CBR test procedure on site and how does the process work?

 

What is the definition of CBR?

The process of CBR testing can sound complicated for some people to understand but here is a simpler explanation. CBR is the ratio of the force required per unit area that is needed to penetrate the soil mass. It is with the standard circular piston at the rate of 1.25mm/min. Developed by the California State Highway Department (USA)before the second world war the California Bearing Ratio Test is a test that evaluates the bearing capacity of subgrade soil. The test is carried out on natural lands in or out of water conditions. The test results are then compared with the standard test curves.It was developed to measure the load bearing strength when building roads. This test is significant during construction.

 

It is done to get an idea of how the heavy the subgrade soil is. Some of the tools used in the process include.

 

 

  • Mould
  • A working and reliable Steel Cutting collar
  • Spacer Disc
  • Good quality Dail gauges
  • Surcharge weight
  • An active penetration Plunger
  • IS Sieves
  • A proper working Loading Machine
  • And other Miscellaneous Apparatus.

These are just some of the apparatus that may be needed. However, the test will determine the tools being used depending on how extensive it will be and the size of the site.The process can be done by professional especially for massive projects.

The process of CBR testing on site.

Three specimens of about 7kg are compacted to range the density from 95% to 100%.

The negative Mould has to be weighed. Add some water into the first specimen and compact into five layers this is by giving ten blows per layer. After this is done remove the collar, then go ahead and level the surface.It is no time to take a sample of the moisture content then weigh the Mould and the compacted specimen.If it is a soaked CBR, you can soak the tank for a few days. Then you should take the bowls and apply different samples then repeat the process. Ater waiting for atleast for days measure the swell reading. Go ahead and drain the water by removing the Mould for the tank.

 

Subcharge a load of 10lb after placing the specimen under the penetration piston. This is the time to apply and take notes on the penetration values. Then it is time to draw a graph between the penetration and penetration load. This is how you find the value of the CBR. A chart between the percentage CBR and Dry density will help you find the CBR at the compaction degree.

 

What is the importance of the CBR test?

 

It is one of the most common ways of evaluating sub grade soil strength. Also the sub base, base course material and determining the thickness of the highway designs and also the width of the airfield pavements.It will determine how flexible the pavement can get.

 

The more the CBR, the stronger the soil. The density could be less, and so the CBR will be very minimal.