Abstract

The importance of surface roughness and its non-destructive examination has often been emphasised in structural rehabilitation. The presented innovative procedure enables the estimation of concrete-to-concrete strength based on a combination of low-cost, area-limited tests and geostatistical methods. The new method removes the shortcomings of the existing one, i.e., it is neither qualitative nor subjective. The interface strength factors, cohesion and friction, can be estimated accurately based on the collected data on a surface texture. The data acquisition needed to create digital models of the concrete surface can be performed by terrestrial close-range photogrammetry or other methods. In the presented procedure, limitations to the availability of concrete surfaces are overcome by the generation of subsequential Gaussian random fields (via height profiles) based on the semivariograms fitted to the digital surface models. In this way, the randomness of the surface texture is reproduced. The selected roughness parameters, such as mean valley depth and, most importantly, the geostatistical semivariogram parameter sill, were transformed into contact bond strength parameters based on the available strength tests. The proposed procedure estimates the interface bond strength based on the geostatistical methods applied to the numerical surface model and can be used in practical and theoretical applications.

Highlights

  • Concrete layers of considerably different ages are frequently used in new and existing structures

  • Point cloud acquisition (with known coordinates (x,y,z) representing sample surface) with an adequate accuracy; surface assessment with use of geostatistical methods, i.e., fitting of theoretical semivariogram to empirical data; generation of Gaussian random field based on the fitted semivariogram; computation of the roughness/texture parameters based on the generated profiles or surfaces; correlation analysis of the semivariogram parameters with shear strength factors throughout roughness/texture parameters

  • The five concrete surface samples (P0, P20, P21, P22, P23) described in Section 2.2 were examined with the use of close-range photogrammetry (CRP)

Read more

Summary

Introduction

Concrete layers of considerably different ages are frequently used in new and existing (strengthening) structures. Based on samples of limited dimensions, the presented method detects surface parameters and extends the results to a larger concrete area. Determination of the surface parameters, i.e., point cloud coordinates and profile height (x,y,z), was obtained using close-range photogrammetry. Professional photogrammetric cameras equipped with high-quality lenses take metric photos with known orientations in the adopted reference system. These photos include elements of internal orientation, which allows researchers to read the coordinates of the photographed objects. Based on these coordinates, it is possible to control the shape of structural elements and their location in space

Objectives
Methods
Results
Conclusion
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call