I produced a graph between differential pore size as a function of V. How can I find the critical pore diameter? I know the peaks represent the critical pore diameters, but how can I explain the phenomena?
The critical pore size is defined as the diameter of the pore that completes the
first interconnected pore pathway in the pores network of the concrete or the cement matrix. Thus, it represents the second sharp inflection point on the cumulative Mercury intrusion curve ( MIP test). This point will appear as a maximum peak in the derivative of the Mercury intrusion curve. It should be highlighted here that the first inflection point represents the threshold pore diameter which is bigger in value compared to that of critical pore diameter and it is a start point where the the pores begin to percolate. The attached figure explain how to determine porosity, threshold and critical pore diameter from the MIP data.
The critical pore size is defined as the diameter of the pore that completes the
first interconnected pore pathway in the pores network of the concrete or the cement matrix. Thus, it represents the second sharp inflection point on the cumulative Mercury intrusion curve ( MIP test). This point will appear as a maximum peak in the derivative of the Mercury intrusion curve. It should be highlighted here that the first inflection point represents the threshold pore diameter which is bigger in value compared to that of critical pore diameter and it is a start point where the the pores begin to percolate. The attached figure explain how to determine porosity, threshold and critical pore diameter from the MIP data.
Thank you for the information. Now should I combine the two graphs in the attachments(They are for 3 samples) ?
also what is that total porosity sir?
Yes (if they are for the same type of concrete, mortar or grout). However, the sample with the blue line seems for different type because of dissimilar trend compared with the others. You can find the porosity value from the original data of the MIP for each sample and then, you can take the average value for the three samples (if they are for same type). However, if you do not have the original MIP file, the porosity is the maximum value of intruded volume in cm3 as shown in the Fig. in my first reply.
Regards
I forget to say that you do not need to combine the two figures. You can leave them separated if you want.
I used this formula for %porosity = Pore Volume Intruded/(weight of sample/density of sample).
Also how to calculate the specific area of the pores. I did try it.
I'am attaching a excel sheet of all the calculation I maded please review the specific area calculations. Thank you
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