Research on the Mechanical Behavior of High Strength Concrete

Bases on experimental investigations of HSC and NSC, HSC’s mechanical behavior, failure mechanism, fracture toughness, characteristic length and damage feature are discussed in the paper, and the formula for flexural strength and comparative toughness is given. The results show that the HSC has a good uniformity of structural entity and large cracking resistance. In addition, HSC is more brittle and more vulnerable to damage than NSC.

Evaluation of Fracture Toughness Characteristic for Nuclear Piping Using Various Types of Specimens

The leak-before-break (LBB) concept is based on the fracture resistance curve obtained by J-R tests on various types of specimens. But it has been also known that the fracture toughness data by various types of specimens are different each other. For example, the estimates for fracture toughness of standard specimens are conservative when compared to the fracture toughness of real pipes owing to the difference of the constraint effect between real pipes and standard specimens. Therefore for estimating the integrity of real pipes on the basis of elastic-plastic fracture mechanics, we have to first establish the relations among real pipes, standard CT specimens and curved CT specimens. In this study, we performed the fracture toughness tests for nuclear piping material by various types of specimen. And each J-R curve considered in the constraint effect was compared.