Dear Tadele Yigrem Yes you can conduct a flexural strength test for plain concrete having pozzolanic materials as a partial replacement of cement. I think in this case, you should concern about the percentage of replacement. For different types of pozzolanic materials, the percentage of cement replacement is different. You can get the proper idea if go through some review papers. Here I attach you some experimental paper for your better understanding.

Thank You, dear!🙏🙏 it means a lot to me.

Dear Tadele Yigrem,

You are interested to conduct flexural test on concrete with partial replacement of cement by pozzolanic material like fly ash . Normally, pozzolanic material increases setting time of mix and 7 day's strength is less as compared to normal concrete. You can use suitable admixture for getting benefit.

Ishwar Sonar Thank you, sir! that's a good point for me to look at.

Tadele Yigre

If good quality pozzolanic material is added in suitable quantity ( normally less than 15% by weight of cement) , long term strength of concrete ( approximately after 50 days ) may increase as compared to concrete without use of Pozzolanic material.

Ishwar Sonar

Okay, I am combining Marble and Volcanic Scoria and replacing cement up to 20% with 5% intervals. 90 days curing period is included for the investigation of compressive strength. but for flexural and splitting tensile strength tests am using 7, 14 and, 28 days of curing periods. If you have any suggestions, please!

On the same line of compressive strength, 7 days and 14 days split and flexural results may show lesser values of variation may be more.