Cbr load

[Geokhan]

Hi....while performing cbr test,why the cbr mould give lower load value at higher penetration depth. While in daily life experiances when some thing achieved more penetration it will experiance more resistance by the other thing...why not soaked mould of cbr follow this rule

 

[Geokhan]

Is this beacause of that first layer of soil in cbr mold get more compactive enegry and become more compected as compare to the last layer. Because we rotate the cbr mold in an upside down maner and plunger start penetration from first laye of the mold(bottom layer in cbr mold preparation).Amvi right or not?.

 

[Geokhan]

Ron,BigGuy,Gtg,GEG and Eri and many more plz put some lights

 

[geotechguy1]

The CBR test does give a higher load at higher penetration depth (see examples here

https://www.aboutcivil.org/california-bearing-ratio-test.html)

 

[Ron]

The load in a CBR test increases until the soil fails in bearing, then the load drops off.

 

[Geokhan]

The CBR is generally selected at 2.54 mm (0.10 in.) penetration. If the ratio at 5.08 mm (0.20 in.)
penetration is greater, the test shall be rerun. If the check test gives a similar result, the ratio at
5.08 mm (0.20 in.) penetration shall be used (aashto T193-99…2003)Thn what does this mean?

 

[DirtyVoodoo]

The standard expects the CBR for a soil to peak before reaching 5mm/0.2in. If it doesn't, re-check your work. If it really did hold up that long then use 5mm/0.2in.