scholarly journals A New Method to Determine the Steel Fibre Content of Existing Structures—Evaluation and Validation

2022 ◽  
Vol 12 (1) ◽  
pp. 454
Author(s):  
Simon Cleven ◽  
Michael Raupach ◽  
Thomas Matschei
Keyword(s):  
Reinforced Concrete ◽  
Steel Fibre ◽  
Concrete Structures ◽  
Test Method ◽  
Fibre Content ◽  
New Method ◽  
Fibre Reinforced Concrete ◽  
Steel Fibre Reinforced Concrete ◽  
Existing Structures ◽  
Non Destructive

The in-situ measurement of the content and orientation of steel fibres in concrete structures is of great importance for the assessment of their specific mechanical properties, especially in the case of repair. For existing structures, the actual fibre content as well as the orientation of the fibres, which is based on many factors such as casting or compacting direction, is typically unknown. For structural maintenance or rehabilitation, those factors have to be determined in order to apply meaningful structural design calculations and plan necessary strengthening methods. For this reason, a new method based on the analysis of drilling cores of concrete structures has been established. The newly developed non-destructive test setup used in this research consists of a framework for cylindrical specimens in combination with an LCR meter to determine the electrical resistance of the fibre reinforced concrete. In combination with a suitable FEM model, concretes with fibre contents up 80 kg/m3 were analysed to derive a first model to assess the actual fibre content of steel fibre reinforced concretes. After a calibration of the literature’s equation by use of an adjusted aspect ratio for the analysis of drilling cores, the estimation of the fibre content is possible with high accuracy for the tested material combination. The results show that the newly developed test method is suitable for the rapid and non-destructive structural diagnosis of the fibre content of steel fibre reinforced concrete based on drilling cores using electrical resistivity measurements.

scholarly journals A New Method to Determine the Steel Fibre Content of Existing Structures—Test Setup and Numerical Simulation

2022 ◽  
Vol 12 (2) ◽  
pp. 561
Author(s):  
Simon Cleven ◽  
Michael Raupach ◽  
Thomas Matschei
Keyword(s):  
Steel Fibre ◽  
Fibre Content ◽  
Fibre Reinforced Concrete ◽  
Missing Information ◽  
Concrete Composition ◽  
Test Setup ◽  
Steel Fibre Reinforced Concrete ◽  
Additional Information ◽  
Existing Structures ◽  
Laboratory Investigations

The diagnostics of constructions built with steel fibre reinforced concrete are extremely difficult to conduct because, typically, no information on the actual amount and orientation of the fibres is available. Therefore, it is of great interest to engineers to have the possibility to determine the steel fibre content and, at best, also the orientation of the fibres in existing structures. For this purpose, an easy-to-use test setup was developed and tested, in the course of laboratory investigations. This method can be used for cylinders, for example drilling cores, that can later be taken of existing structures, to determine both the fibre content and orientation. Based on these results, a model for cylindrical specimens was derived, which can be used for varying concrete compositions with steel fibre contents of up to 80 kg/m3. In the case of missing information concerning the concrete composition, it allows an initial estimation for the fibre content. In case additional information about the concrete composition is available, a much higher accuracy of the projected steel fibre content and therefore, an assessment of the building’s condition is possible.

scholarly journals Impact Response of Plates Under Drop Weight Impact Testing

1970 ◽  
Vol 7 (1) ◽  
pp. 1-11 ◽  
Author(s):  
S Elavenil ◽  
GM Samuel Knight
Keyword(s):  
Reinforced Concrete ◽  
Aspect Ratio ◽  
Energy Absorption ◽  
Steel Fibre ◽  
Impact Resistance ◽  
Impact Testing ◽  
Fibre Content ◽  
Fibre Reinforced Concrete ◽  
Steel Fibre Reinforced Concrete ◽  
Drop Weight

Concrete structures are often subjected to long term static and short term dynamic loads. Due to a relatively low tensile strength and energy dissipating characteristics, the impact resistance of concrete is poor. Research work carried out so far towards the development of concrete that exhibits improved impact resistance than conventional concrete showed that the steel fibre reinforced concrete has a good potential as a viable structural material for such applications. The overall objective of the study is to investigate the dynamic behaviour of steel fibre reinforced concrete plates under impact loading with respect to displacement, velocity and acceleration. In the drop weight test, eighteen plate specimens were tested with three different thicknesses of 20,25 and 30mm and with three different steel fibre contents of 0.5,0.75 and 1%.The edges of the plates were fixed on all sides. Displacement versus time, velocity versus time and acceleration versus time behaviour for all the plates tested were studied. It was found that when the aspect ratio of fibres is 50 and 75 there is a marginal increase in energy absorption for change in fibre content from 0.5 to 0.75%. There is a steep increase in energy absorption for a steel fibre content of 1% when the aspect ratio of fibre is 100.DOI: http://dx.doi.org/10.3329/diujst.v7i1.9580Daffodil International University Journal of Science and Technology Vol.7(1) 2012 1-11

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