Researchers from the University of Burgos, in collaboration with other research centers, have described a new invention that consists of the geometric definition of a specimen to carry out characterization tests of the tensile strength of concrete and other secondary binding materials, specific for the direct tensile test.
New and innovative aspects
Tensile characterization tests of concrete and other secondary binder materials are mainly carried out by means of indirect tensile tests, which are simpler from the point of view of their execution, but less reliable. Direct tensile tests, being more complex, are less common. There is no standard specimen geometry for these tests, and specimens with a wide variety of geometries have been used. The geometric design of the test specimen is essential for successful direct tensile testing.
The solution proposed by the researchers makes it possible to determine geometrically a test specimen that guarantees that the break will occur, in the highest possible proportion, in the central area and that it is not affected by the local effects derived from the anchoring system. from the specimen to the load application system.
Main advantages of its use
This specimen is intended to serve as a basis for conducting, in a more reliable way, direct traction tests on concrete and other secondary binding materials, in such a way that all the specimen show a break in the central zone and, therefore, all direct traction tests can reach the "valid" condition.
The geometry of the test specimen described by the researchers by the present invention comprises a body of revolution made up of a central straight section, first and second straight end sections, and two first and second transition curved sections, which are arranged between the straight section. central and the first and second extreme straight sections respectively. This proposed specimen manages to substantially reduce the quotient between the maximum stress in the specimen and the maximum stress in its central straight section, approaching unity. To do this, the maximum principal tensile stress fields that appear in different examples of specimens have been calculated, all of them, with a geometry of revolution, subjected to a uniform tensile load, in such a way that the maximum principal stress in the area of the central straight section is the unit.
This specimen is of great interest for laboratories for the characterization of hydraulic binding materials (such as concrete, cement mortars, lime mortars or plaster mortars, among others). It is also of interest to research centers that are investigating the mechanical properties of concretes and secondary binding materials.
Intellectual property status
Protected by patent P202130588
Current development status
Developed exclusively in the laboratory and validated for industrialization
Desired business relationship
Commercial Agreement, License Agreement, Technical Cooperation: further development; Technical Cooperation: testing new applications; Technical Cooperation: adaptation to specific needs.