Hello All
In my research project, I find a problem in the mechanical analysis of the calcareous soil
the carbonate percentage range from 30 to 60 %
is the mechanical analysis carried out to the bulk sample or to the clastic contents ?
in the two cases above
is these procedure is significant for the sample contains lower clastic percentages ?
Also, if the analysis carried out to the bulk sample
how could we minimize the carbonate effect in the coagulation and sedimentation rate ??
thanks for all
For mechanical analyses of the soils there are metods which are simpler. For eg hydrometer method.
For quntitative labs the method often followed is of Jackson (1979). It invoves removal of cementing agent sin a stepwise manner. Carbonate for highly calcareous soils and sesquioxides for the red soils require diffrent quantum of time to remove these two types of cementing agents. Besides., OM is another component which cements particles and need to be removed by H2O2. So it is not that calcareous soils which will pose problem.
After all these we qualtify sand , silt and clay; can also gor for subfractination of san, silt and clay depending on type of research one is engaged in.
After getting these values of soil separates one can make a realistic estimates of all cementing agents to make the total 100.
Regards
tapas
Please check the following link and PDF attachments.
https://www.cabdirect.org/cabdirect/abstract/19729900205
Please check the following link also.
https://www.researchgate.net/publication/300095633_Physico-chemical_characteristics_of_calcareous_soils_in_district_Deoria_and_Gorakhpur_of_Eastern_Uttar_Pradesh
Article Physico-chemical characteristics of calcareous soils in dist...
For clacareous soil you should remove all carbonate what ever the percentage of clastics. Size anaysis is characterized for clastics. you need to remove the cabonate and anayze the clastic poetion
many thanks Dr. Arvind Singh for your cooperation and these helpful papers
Thanks Dr. Hesham for your participation
But, the question Now is the grain size analysis for the 30 % or 40 % clastic is significant
the carbonate percentage is up to 60 % in some samples
Also, what about the carbonate sand ?
Hi Mahmoud
In our lab we found that the cementation of soil particle is started when the content of CaCo3 reached 14% and actually the particle size distribution was affected. Your CaCo3 is up to 60 %, you have to remove the CaCo3 content by using Hydrochloric acid (Hcl) and after that proceed mechanical analysis, in our experiment we used Hcl and the difference in clay content for hydrochloric acid treated and untreated samples was highly significant.
Hi Mahmoud, The calculation of the clastic portion depends on the purpose of this analysis in your study. Howevere, you can do such analysis for any clastc percent of the sample it will halp you also for nomenclature of the soil samples according to folk
Dear Mahmoud,
Despite the standard procedures mostly assume you should remove the carbonates, you should think about what you're actually measuring. With such high carbonate percentage, you can expect that complete particles are made up of carbonates and they form an important part of the soil/sediment composition.
During my master thesis I worked also with soils containing 30-45% of carbonates and I removed the organical boundings by an excess of peroxide (till no longer a reaction was visible) and we used dispersant to prevent coagulation during the measuring.
Good luck with your research!
For mechanical analyses of the soils there are metods which are simpler. For eg hydrometer method.
For quntitative labs the method often followed is of Jackson (1979). It invoves removal of cementing agent sin a stepwise manner. Carbonate for highly calcareous soils and sesquioxides for the red soils require diffrent quantum of time to remove these two types of cementing agents. Besides., OM is another component which cements particles and need to be removed by H2O2. So it is not that calcareous soils which will pose problem.
After all these we qualtify sand , silt and clay; can also gor for subfractination of san, silt and clay depending on type of research one is engaged in.
After getting these values of soil separates one can make a realistic estimates of all cementing agents to make the total 100.
Regards
tapas
Interesting discussion ...i am struck with three genuine issues..
*How will you work , what portion of calcium carbonate is stuck with which soil fraction..?
* Since calcium carbonate is an integral part of calcareous soils , removal of calcium carbonate from the soil prior to textural analysis , dont you think , will give erroneous picture about original texture of so called calcareous soils..?
* How will you work out the desired concentration of dispersing agent to be able to disperse the soil particles in such soils containing such high calcium carbonate ..?
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