Bond Behavior between Concrete and Self-Expansion Polymer Material under Normal Pressures

Xinxin Li,Yingchun Fu,Fuming Wang,Dan Zheng,Hongyuan Fang,Qiang Tang

doi:10.1155/2021/6675102

Xinxin Li, Yingchun Fu + Show 4 more

Open Access

https://doi.org/10.1155/2021/6675102

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Abstract

Self-expansion polymer grouting technology is a new rapid trenchless method for repairing leakage and subsidence of underground concrete structures. The bond between polymer and concrete is critical to determine the ultimate conditions of repaired concrete. In this paper, a series of direct shear tests were performed to investigate the influence of normal pressure on the shear bond properties between self-expansion polymer and concrete with different polymer density and concrete strength. Results indicate that failure modes and bond strength are greatly influenced by the normal pressure for specimens with a lower polymer density. For a given normal pressure, the bond strength linearly increases with the increasing polymer density. As the polymer density increased up to 0.43 g/cm3, the increased ratio decreases with the polymer density. Moreover, the displacement at the peak point reduces with an increase in polymer density. Finally, a finite element model is proposed to evaluate the bond strength for specimen failure in concrete and verified with the test results.

Highlights

A polyurethane polymer material with the characteristics of self-expansion [1], lightweight [2], early strength [3], high tensile strength [4], and excellent water resistance [5] has been successfully and effectively used to repair underground structures such as tunnels, road foundations, dams, and concrete pipelines [6, 7]
A total of 105 composite specimens have been prepared and tested to evaluate the effect of normal pressure on the shear bond behavior of concrete and self-expansion polyurethane polymer under different polymer density and concrete strength. e conclusions can be drawn as follows: (1) e failure mode is mainly related to the magnitude of polymer density and normal pressure
For specimens with a lower polymer density, the failure mode changes with the increase of normal pressure

Summary

Introduction

A polyurethane polymer material with the characteristics of self-expansion [1], lightweight [2], early strength [3], high tensile strength [4], and excellent water resistance [5] has been successfully and effectively used to repair underground structures such as tunnels, road foundations, dams, and concrete pipelines [6, 7]. Erefore, it is critical to study the shear bond performance of the self-expansion polymer and concrete for accurately evaluating the response of polymer reinforced underground concrete structures under external loading [9]. Erefore, to accurately evaluate the overall performance of polymer-repaired pipelines, the effect of normal stress on the shear bond performance between the selfexpansion polymer and concrete should be considered. E effects of polymer density, the magnitude of normal pressure, and the strength of concrete on the failure mode, bond parameters, and shear bond stress-slip curves are analyzed. Is paper aims to present an experimental investigation to quantify the normal pressure on the shear bond behavior between self-expansion polymer and concrete. e effects of polymer density, the magnitude of normal pressure, and the strength of concrete on the failure mode, bond parameters, and shear bond stress-slip curves are analyzed. en, a shear bond strength model for specimen failure in concrete is proposed

Experimental Program

Testing Results and Discussions

C15 C30 C45

Conclusions