Self-balancing test device and method for directly testing axial tensile strength of early-age concrete

Abstract

The invention discloses a self-balancing test device and a method for directly testing axial tensile strength of early-age concrete. The testing device consists of an outer framework, an inner template, a dowel bar, a hydraulic hollow jack, a hollow load sensor, a ball hinge, a lock nut, a polyfluortetraethylene plate, a hydraulic oil pump and a resistance strain gauge. When testing, a side template in the inner template is removed, and an end template in the inner template and a side plate in the outer framework which are fixed are loosened; the dowel bar is fixed in the center of the end template in the inner template; the hydraulic oil pump drives the hydraulic hollow jack; and the end template and the hydraulic hollow jack move together to break a concrete test piece to test the axial tensile strength of the early-age concrete. The testing device has simple structure, convenient assembly and disassembly and less required materials and equipment, and is suitable for scientific research and testing the axial tensile strength of the early-age concrete in construction site.

Description

technical field [0001] The invention relates to a self-balance test device and a test method for measuring the early axial tensile strength of concrete, which belong to the field of concrete construction. Background technique [0002] In the field of civil engineering, the axial tensile strength of concrete at an early age (mainly after the concrete is hardened and before the formwork is removed) is very important. In the early age of concrete structures, the axial tensile strength of concrete materials develops rapidly, and its law has not been fully grasped, and the axial tensile strength of early-age concrete determines its cracking performance. Accurately measure the axial tensile strength of early-age concrete The axial tensile strength is of great significance for evaluating the cracking performance of concrete at an early age and avoiding cracks in early-age concrete structures. [0003] At present, there are mainly direct tensile test and indirect test methods to me...

AI Technical Summary

Problems solved by technology

On the other hand, the flexural tensile strength and splitting tensile strength cannot really reflect the direct tensile strength of concrete.

When using the existing tensile strength test method to measure the axial tensile strength of early-age concrete, it is necessary to remove the formwork and move the specimen, which will cause damage to the concrete specimen, making the test impossible or the success rate of the test extremely low. Low

In addition, due to the low strength of early-age concrete, the pre-embedded steel bars may slip out of the concrete, making the test fail

The external clamping method will cause premature failure of the specimen due to local stress concentration, making the test fail

The pasting method cannot measure the axial tensile strength of early-age concrete because of the high humidity on the surface of early-age concrete and the curing of the glue takes a long time

Images