Method for testing expansion/contraction stress of cement-based material

Abstract

The invention relates to a method for testing expansion / contraction stress of a cement-based material, which adopts a device for testing the expansion / contraction stress of the cement-based material is adopted. The device comprises inner and outer circular rings which are coaxially arranged and have the same height, and a strain testing device and a data acquisition device which are mutually electrically connected, wherein the materials of the inner and the outer circular rings are the same; the strain testing device comprises a plurality of testing strain gauges; the strain gauges are distributed on the external surface of the outer circular ring and the internal surface of the inner circular ring uniformly along a circumferential direction, and each testing strain gauge is electrically connected with the data acquisition device; the cement-based material is poured between the inner and the outer circular rings, and the strain of the inner and the outer circular rings is tested; and the expansion / contraction stress at a position where the internal radius of the cement-based material is r is calculated according to a formula (I). The method has the advantages that a, the test device is simple, and the operation is simple and convenient; b, restraint stress is uniform; and c, the method can test at the initial stage of watering moulding without moving test specimens, and continuous and automatic test.

Description

technical field

[0001] The invention relates to a cement-based material expansion / shrinkage stress test method, which can evaluate the expansion effect of an expansion agent used to prepare shrinkage-compensating concrete, and belongs to the technical field of cement-based material testing. Background technique

[0002] Shrinkage-compensated concrete refers to the concrete that is mixed with expansive agent or expansive cement to produce moderate expansion and certain self-stress under certain constraints. It is mainly used for structural self-waterproofing, filling expansion second-phase project, continuous pouring reinforced concrete project and mass concrete project for extending the distance between building expansion joints or post-casting strips. The expansion component relies on its own chemical reaction or reacts with other components of the cement to produce a certain limited expansion compensation or partially compensate for the shrinkage of the concrete during the...

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