Device and method for testing interlaminar tensile strength of 3D printed concrete member

Abstract

The invention discloses a method for testing the interlaminar tensile strength of a 3D printed concrete member. The method comprises the steps of placing test pieces between brackets, and placing a pressure head on one test piece; enabling the pressure head to be in contact with a pressure head of a universal material testing machine, starting to press down, and measuring force F during fracture;and according to the area S of the crossed part of the two test pieces, obtaining the tensile strength Pten of the 3D printed test piece, namely, indicating that Pten = F / S. According to the testing device provided by the invention, grooves are formed in the parts, in direct contact with the test piece, of the brackets, in order to concentrate force during testing on the crossed part of the two test pieces, so that a test error is reduced; and roll balls are further arranged on the brackets, so that the test pieces can be prevented from being stuck in a testing process. According to the testing device and method provided by the invention, the axial tensile strength of the 3D printed concrete member can be obtained directly; the related problems that the stress direction is not clear, the fracture surface is not controllable and the like in a pull-off method are solved; the success rate of testing is greatly improved; the testing principle is simple and clear; and the reliability is high.

Description

technical field [0001] The invention relates to the technical field of concrete structure testing, in particular to a device and method for testing interlayer tensile strength of 3D printed concrete components. Background technique [0002] At present, the 3D printing of cement-based materials is mainly based on extrusion and accumulation. The extrusion head is controlled by the program, and the layers are accumulated and formed. Unlike the traditional cement-based material pouring process, 3D printing technology involves layering and stacking to create interfaces between layers. The bonding interface is the weak point of the overall structure. When the specimen is damaged by force, the damage occurs first at the interlayer interface rather than the printed material matrix. Therefore, it is necessary to evaluate the interlayer bonding strength of 3D printed cement-based materials. [0003] The existing pull-out method (BS EN 14488–4:2005+A1:2008) tests 3D printed concrete c...

AI Technical Summary

Problems solved by technology

Because it is an alternative, the split tensile test does not directly measure the interlayer axial tensile strength of 3D printed cement-based materials, and for 3D printed concrete components with obvious orientation and interfacial delamination, the split tensile test The effect of the test to indirectly characterize the interlayer tensile strength is also open to question

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