Is flexural strength testing a more reliable basis for accepting or rejecting concrete than compression testing?
Unfortunately flexural strengths determined from specimens molded and initially cured in the field show wide variations which have no bearing on the strength producing properties of the concrete. This seems to be largely a result of the extreme sensitivity of this particular test to the amount and distribution of the moisture in the specimen. For this reason it appears that flexural strength testing should be used mainly as a laboratory means for establishing proportions and evaluating ingredients, and not as a field procedure for determining compliance with specifications.