Air dry vs oven dry soil sample for hydrometer test
Air dry vs oven dry soil sample for hydrometer test
(OP)
I like to continue the discuss starting with the thread "Grain Size Distribution by Hydrometer".
According to the Ontario standard. The soil will be oven dry at begining. after having the total weight, the sample will be grinded with a pestle. Sieve it over 2mm sieve. The portion retained will be washed and sived again. The percentage of the soil passing can be calculated then. The sub-sample will be taken from the portion passing the 2mm sieve for the hydrometer analysis.
My question is that the sample for the hydrometer has already been oven dried. For the soil thich has both coarse and fine portion is necessary for these strps. For instance, the maxnominal size of the particle is 10mm and there is significant amount of silt/clay portion.
I can't recall the difference between Ontario standard and ASTM on this aspect.
Any coments? Thank
According to the Ontario standard. The soil will be oven dry at begining. after having the total weight, the sample will be grinded with a pestle. Sieve it over 2mm sieve. The portion retained will be washed and sived again. The percentage of the soil passing can be calculated then. The sub-sample will be taken from the portion passing the 2mm sieve for the hydrometer analysis.
My question is that the sample for the hydrometer has already been oven dried. For the soil thich has both coarse and fine portion is necessary for these strps. For instance, the maxnominal size of the particle is 10mm and there is significant amount of silt/clay portion.
I can't recall the difference between Ontario standard and ASTM on this aspect.
Any coments? Thank





RE: Air dry vs oven dry soil sample for hydrometer test
RE: Air dry vs oven dry soil sample for hydrometer test
My question is that the sample has already been oven dried for the 2 mm sieve seperation. why not be allowed to be oven dry again?
RE: Air dry vs oven dry soil sample for hydrometer test
RE: Air dry vs oven dry soil sample for hydrometer test
RE: Air dry vs oven dry soil sample for hydrometer test
1. Saperate the air dried sample with 2mm sieve.
2. Weigh the air dried weight of the passing
3. Take a sub-sample from passing for the hydrometer, and take another sub-sample from passing for Hydroscopic Factor. This way we can get dry weight of the passing (A).
4. oven dry the material retained on 2mm. this way we can get total dry weight of the retained (B). wet sieve it and get true dry weight of retained (C)
5. True percentage of passing is (A+B-C)/(A+B)