Look at page 34. Maybe it will help you

.

http://210.42.35.80/G2S/eWebEditor/uploadfile/20110806224824222.pdf

Dear Sergey Makarenko,

Thanks for your help. I will check it.

There are some recommendations for this relationships. The are shown in Sergey Makarenko link. They are also in Eurocode 2 (EN 1992-1-1) and in Model Code 2010. Probably they are similar.

Nguyen Van Quang, you have to be careful because relationships f.ct - f.c and E.cm-f.c can be dependant on various things (some of them are not in codes) for example: quality of aggregate. In some countries some rocks are stronger then other rocks from the same type.

Daer Piotr Soka!

Thank you very much. I have seen somes equation. In ACI, fspt (split tensile strength) = fct? because I did not find fct so I think that fsct and fct are one thing. Is that right?

dear nguyen, 

       The Relationship between Compressive Strength – Split Tensile Strength is given by

ft= 0.043fck

1.064 with coefficient of variation R² = 0.990

The Relationship between Compressive Strength –Flexural Strength is given by

fcr=0.031fck1.125 with coefficient of variation R² = 0.989

Hello Nguyen

I found the following document, based on EC2, quite useful and it may answer your question:

http://sefindia.org/forum/files/properties_of_concrete_for_use_in_eurocode_2_135.pdf

Best wishes 

Dear Sanaa Abdulhadi,

Can you show me the materials that have mentioned equations? I have seen AIC 318, it report that fct = 0.56sqrt(fc). I have compared to results from your equation and results are not same ( i mean double time difference). 

https://www.researchgate.net/publication/251231886_RELATIONSHIP_BETWEEN_SPLITTING_TENSILE_STRENGTH_AND_COMPRESSIVE_STRENGTH_OF_CONCRETE_AT_EARLY_AGE_WITH_DIFFERENT_TYPES_OF_CEMENTS_AND_CURING_TEMPERATUREHISTORIES

Conference Paper RELATIONSHIP BETWEEN SPLITTING TENSILE STRENGTH AND COMPRESS...

Thank you so much, Messaoud Saïdani!

I know it's a question from almost 1 year ago, but may be it is helpful for somebody searching relationships of tensile strength, compressive strength and elastic modulus of normal weight concrete:

http://framcos.org/FraMCoS-6/415.pdf

http://210.42.35.80/G2S/eWebEditor/uploadfile/20110806224824222.pdf

In the design of concrete structures, engineers have the flexibility to specify particular concrete type(s) aimed at meeting the specific performance requirements for their project. For instance, where calculated deflections exceed serviceability limits, the designer can achieve lower deflections by increasing the class of concrete and the associated modulus of elasticity, rather than by resizing members

Numerical Relationship

It is expected that these two types of strengths are closely related, but there is no direct proportionality. It is noticed that with the increment of compressive strength, the tensile strength is also increased but at a decreasing rate.

A better correlation is found between the various measures of tensile strength and the square root of the compressive strength. A number of empirical formulae connecting ft and fc´ have been suggested, many of them of the following type:

ft = k (fc)n

where k and n are co-efficients. Values of n between ½ and ¾ have been suggested. The former value is used by the American Concrete Institute, but Gardner and Poon found a value near the later, cylinders being used in both cases. Probably the best fit overall is given by the expression:

ft = 0.3 (fc)2/3

where, ft is the splitting strength, and fc´is the compressive strength of cylinders, both in megapascal. If the stress is expressed in pounds per square inch the co-efficient is replaced by 1.7. The above expression was suggested by Raphael. A modification of Oluokun is

ft = 0.2 (fc)0.7

where the strength are in megapascals; the co-efficient becomes 1.4 in psi.

An expression used in British Code of practice BS 8007:1987 is similar, namely

ft = 0.12 (fc)0.7

Bearing in mind that the compressive strength is determined on cubes( in megapascals); ft represents the direct tensile strength.

The difference between the various expressions are not large. What is important, however, is that the power exponent used in the ACI Building Code 318-89( revised 1992) is too low so that the splitting strength is overestimated at low compressive strengths and underestimated at high compressive strength.

These approximate expressions show that tension and compression strength are by no means proportional, and trhat any incrase in compression strength, such as that achieved by lowering the water- cement ration, is accompanied by a much smaller percentage increase in tension strength.

Hi Nguyen,

you can find an intensive evaluation of the relationship between fct, Ec and also GF and fc with the use of large experimental databases in the following paper:

Article Uncertainties of concrete parameters in shear capacity calcu...

Best regards,

Ngoc Linh Tran