Flexural Strength of Concrete

[MikeKostiz]

What is a conservative value to use for the flexural strength of concrete in a concrete road based on materials available in Stanislaus County, California.

 

[PaulEmil]

If you design the concrete mix to attain a compressive strength of 5000 psi in 28 days it will probably achieve a flexual strength of approx. 600 psi in 28 days. The local aggregates are a major factor in this relationship and cylinder tesitng must be called for to substansiate this possible relationship.

 

[Rjeffery]

Also note that natural aggregate filler will give a lower flex. strength that crushed rock as the matrix does not develop well on smooth stone. Therefore specify manmade and not natural (bank run) aggregate.

PaulEmil's idea of companion testing of cylinders and beams is also an excellent one. perfect advice.

 

[BobSmith54]

i am looking for a text or a link that could indicate what are the desired type of concrete cyl. breaks... What are the desired types of failures. I am talking about 3000 PSI to 4000 PSI concrete, not high strength cylinders. It is and has been my exsperience that a conical compression break is and has been the desired. Reciently it was presented to me that conical (cone)(a), and Shear as well as Column failures are OK. All feed back welcome. I have been doing this for 30 years and have seen many many cylinders pass thru my labs have not been able to find the support I am looking for in the texts that I have am always looking to hear from others as well.

Thanks in advance