Linear swell from CBR

[killswitchengage]

Hello
What is the use of the linear swell from CBR test ? is it just to evaluate the efficiency of the chosen soil stabilization method ( as in hydraulically bound soils) or can you determine if the swell is dangerous or not, like in the case of free swell test on soils ?

 

[fattdad]

we (Virginia DOT) use the swell as a go/no-go criterion along with organic content, the actual CBR result, Atterberg limits and sand content (i.e., some group names are no good, by contract).

f-d

ípapß gordo ainÆt no madre flaca!

 

[killswitchengage]

Thank you now i am starting to get some new info
so what are the threshold beyond which the swell is considered inadmissible

 

[fattdad]

we use 5 percent.

f-d

ípapß gordo ainÆt no madre flaca!

 

[killswitchengage]

i appreciate your help thanks

 

[Okiryu]

In Japan, normally 1% is used to define good subgrades.

 

[GoMizzou99]

EXPANSIVE SOILS by Nelson & Miller references Altmeyer (1955) and provides the following guidance about swelling soils:
[ul]
[li]less than 0.5% - Noncritical[/li]
[li]0.5%-1.5% - Marginal[/li]
[li]greater than 1.5% - Critical[/li]
[/ul]

I find these values to hold true for floor slabs on grade in the central USA - but are somewhat on the conservative side for pavement.

 

[fattdad]

Hi GM99, are those swells as measured in the CBR? I'll go get the citation, but in the interim remain curious. . .

f-d

ípapß gordo ainÆt no madre flaca!

 

[killswitchengage]

you guys rock thank you

 

[GoMizzou99]

FATTDAD - Those swell guidelines are not from CBR tests but rather from One-Dimensional Swell Tests (ASTM D 4546).