DIC (Digital Image Correlation) method in the research of RC beams strengthened with PBO-FRCM materials

Dorota Marcinczak,Tomasz Trapko,A Volkov,A Pustovgar,T Sultanov,A Adamtsevich

doi:10.1051/e3sconf/20199703008

Dorota Marcinczak, Tomasz Trapko + Show 4 more

Open Access

https://doi.org/10.1051/e3sconf/20199703008

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Abstract

The article presents tests of a reinforced concrete beam strengthened in a shear with PBO-FRCM composite materials. Measurement of the deformation of the composite was carried out using two methods - with strain gauges and the optical DIC method (Digital Image Correlation). The DIC method consists in taking a series of photographs of the tested object before and during loading. The surface of the tested element must have randomly spaced spots that are applied to the object before measurement. During the study, the cameras monitor the shifting of spots against each other, which in comparison to the reference image before loading gives information about strains and stresses of the tested element. Measurements of deformation of composite materials using strain gauges are difficult to clearly analyse, because the strain gauge is in a specific, limited place, which does not correspond to the work of the entire composite. In addition, the strain gauge tends to break at the place of crack. The article discusses this problem by presenting the results of deformation of PBO-FRCM composite meshes measured in two mentioned ways, their comparison and discussion of results.

Highlights

Strengthening of reinforced concrete structures with FRCM (Fabric-Reinforced Cementitious Matrix) composite materials is an increasingly recognized way of repairing existing structures
This paper presents a description of the Digital Image Correlation (DIC) method and the results of an experimental study conducted on reinforced concrete T-shaped beams strengthened in a shear with PBO-FRCM composites
The strengthened beam failed in a shear with formation of main diagonal crack, and reached an ultimate load of 527.40 kN. This diagonal crack developed on the half of the span, which was not included in the range of DIC cameras (Fig. 7b)

Summary

Introduction

Strengthening of reinforced concrete structures with FRCM (Fabric-Reinforced Cementitious Matrix) composite materials is an increasingly recognized way of repairing existing structures. This system can be used in environments exposed to high temperatures or fire, and in historical objects. It is related to the use of cement mortar as a matrix, This is related to the use of cement mortar as a matrix, the task of which is to combine fibers with each other and with concrete. The main disadvantage of cement mortar is its granularity, due to which the mortar can not connect all the fibers together, which results in the formation of slip between the fibers and the premature debonding of the fiber mesh from the matrix. Many researchers around the world were taking up the topic of strengthening reinforced concrete elements for bending, shear and compression in order to thoroughly investigate the mechanisms involved in this type of reinforcement [1-6]

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