Tensile creep test device and method for high-strength concrete

Abstract

The invention relates to a tensile creep test device and method for high-strength concrete. A double-spring tensile creep device and a concrete test piece creep strain acquisition method are included.The double-layer spring tension creep device ensures the stability of the loading process and the later-stage load holding by utilizing double springs; a linear differential displacement sensor is arranged on one side of the concrete detection test piece, and a dial indicator detector is arranged on the other side of the concrete detection test piece; on the premise of ensuring that the difference between the two acquisition modes is within an error range, data points of sensors are used in the earlier stage, and the reading point of the dial indicator is used in the later period, and a logarithmic mapping method is used for mapping, so that the instantaneous deformation including elastic deformation in the initial loading stage can be displayed, the deformation in several years cannot beclose to the level, and the limitations that the value of the traditional strain acquisition method cannot be distinguished in a short time and the value of the traditional strain acquisition methodis positioned outside the graph are overcome; the test device and method have the characteristics of simple operation, low cost, reliable data and the like, and are suitable for carrying out tensile creep test for a long time.

Description

technical field [0001] The invention relates to a tensile creep test device and method for high-strength concrete, belonging to the field of concrete structures and materials. Background technique [0002] Creep is an important feature in the study of concrete properties. The traditional research is relatively mature on the creep of mature concrete under compression, but the research on the creep of concrete under tension, especially under the tension state of early concrete, is relatively mature. It is rare. After a large number of tests, it has been shown that whether concrete cracks depends not only on shrinkage, but also is largely affected by tensile creep. Therefore, the study of tensile creep is of great significance. The tensile creep test mainly includes three parts. , that is, the loading method, strain collection and specimen form. [0003] There are many loading methods used in tensile creep devices, but all of them have certain shortcomings. Lever loading is s...

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Problems solved by technology

[0005] In terms of fixing the test piece to the equipment, the usual installation forms of the test piece have the following forms: 1) prefabricated anchors at both ends of the test piece, which destroys the integrity of the test piece; 2) anchors at both ends of the test piece Pasting the steel plate with glue, this form is limited by the tensile strength of the glue, especially when the test specimen is ultra-high performance concrete, it usually breaks at the glue joint, which affects the authenticity of the test data; 3) Fix it with clips The two ends of the specimen are not tightly clamped; 4) The dog bone specimen is used, and the clip is clamped at the contraction of both ends of the dog bone. This clamping form has stress concentration, and the ports are concentrated at the contact point, making the test The error becomes larger

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