Carbon-reinforced concrete (CRC) - research

C - 25 Carbon reinforced concrete under biaxial tensile load

Load-bearing and deformation behavior of carbon reinforced concrete under biaxial tensile load

Carbon reinforced concrete slabs show hygric and temperature-induced deformations in two perpendicular directions. These lead to biaxial stresses in the slab. If a biaxial tensile stress occurs, this results in cracks in the concrete up to yarn breakage. As a result of the interaction between the two load directions, the load-bearing and deformation behavior of carbon reinforced concrete slabs deviates from uniaxial tensile tests.

In this thesis, slabs made of carbon reinforced concrete are to be investigated experimentally under biaxial tensile loading. For this purpose, the results of existing research work on textile and carbon reinforced concrete under biaxial tensile loading are first summarized and compared. Subsequently, experimental investigations on slabs made of carbon reinforced concrete are carried out, evaluated and compared with the findings from the literature research. The aim is to characterize the load-bearing and deformation behavior of carbon reinforced concrete under biaxial tensile loading.

The task will be specified in consultation with the student.

Contact person:
Dipl.-Ing. Jonathan Schmidt
+49-351-463-41118

C - 24 Carbonbetonverstärkte Spannbetonträger

Bewertung des Tragverhaltens von carbonbetonverstärkten Spannbetonträgern

Der Erhalt bestehender Infrastrukturbauwerke hat höchste Priorität. Dennoch existieren im Netz weiterhin viele Brücken, bei denen spannungsrisskorrosionsgefährdete Spannstähle verbaut wurden. Insbesondere dann, wenn das Riss-vor-Bruch-Kriterium nicht erfüllt wird, führt dies häufig zu einem kurzfristigen Abbruch oder Rückbau. Eine Möglichkeit zur Verstärkung solcher Tragwerke bietet die nachträgliche Applikation von Carbonbeton.

Am Institut für Massivbau wurden in Zusammenarbeit mit der Hentschke Bau GmbH Belastungsversuche bis zum Versagen an vier alten Spannbetonbrückenträgern durchgeführt und mithilfe verteilter faseroptischer Sensoren messtechnisch überwacht. Während der erste Träger als Referenz diente, wurden bei drei Trägern Spannglieder gezielt geschädigt. Zwei dieser Träger erhielten anschließend eine Biegeverstärkung durch Carbonbeton.

Im Rahmen der studentischen Arbeit sind die während der Belastungsversuche gewonnenen Messdaten (Photogrammetrie, Faseroptik, konventionelle Messtechnik) auszuwerten und ingenieurwissenschaftlich zu interpretieren. Der Schwerpunkt liegt dabei auf dem Einfluss der Carbonbetonverstärkung auf das Tragverhalten geschädigter Spannbetonträger. Insbesondere der last- bzw. verformungsabhängige Traganteil der Carbonbetonschicht soll zur Überprüfung des Bemessungsmodells anhand der Messdaten herausgearbeitet werden.

Ansprechpartner:
Max Herbers, M. Sc.
+49 351 463 39620

Dr.-Ing. Frank Jesse
Hentschke Bau GmbH
+49 3591 6703-1657

C - 22 Reinforcements made from recycled carbon filaments

Full title: An investigation of reinforcements made from recycled carbon filaments

The recycling of carbon fiber components is becoming increasingly important these days. Due to the increasing demand for carbon fibers, the recycling of end-of-life components made of carbon fibers is becoming more and more essential. As part of the work, a literature research on the recycling methods of carbon fiber components is to be carried out and summarized. In particular, the focus is on compiling international sources. Based on the literature research, tests with reinforcements made from recycled carbon filaments are to be carried out and evaluated.

Sub-tasks of the thesis are:

• Literature research (national/international) on possible ways of recycling carbon fiber components
• Literature research (national/international) on investigations on recycled carbon filaments and the semi-finished products made from them
• Planning, implementation, and evaluation of tests with reinforcements made from recycled carbon filaments.

Contact person:
Dipl.-Ing. Enrico Baumgärtel
0351 463 42631

C - 16 Design tools for CRC

Full title: Set up of one (more) design tools for carbon-reinorced concrete with parameter studie

There are many commercially available software programs for the design of reinforced concrete members. For carbon-reinforced concrete there are none available yet. For this reason, design tools for individual verifications are to be developed within the scope of the work. In addition, various parameter studies are to be carried out with the help of these.

Contact person:
Prof. Dr.-Ing. Alexander Schumann
CARBOCON GmbH, Ammonstraße 72, 01067 Dresden
0351 4820 5511

C - 15 Joint's bearing capacity between old concrete and strengthening layer

Full title: Establishment of a calculation approach for the composite joint load-bearing capacity between the old concrete and the reinforcing layer in carbon-reinforced concrete structural elements

The strengthening of existing steel-reinforced concrete components is one of the fields of application for the composite material carbon-reinforced concrete. The basic suitability of the material for strengthening has already been successfully demonstrated several times. However, the problem is often that, due to the performance of CRC, the bond in the joint between the old concrete and the strengtheing layer has a decisive influence on the failure. More in-depth considerations will be carried out in the course of this work.

Contact person:
Prof. Dr.-Ing. Alexander Schumann
CARBOCON GmbH, Ammonstraße 72, 01067 Dresden
0351 4820 5511

C - 14 Rotational capability andductility of CRC components

Full title: Investigations into the rotational capability or ductility of carbon-reinforced concrete components

Due to its many positive properties, carbon-reinforced concrete has established itself as an alternative to steel-reinforced concrete construction in both reinforcement and new construction. However, some issues have not yet been finally clarified. One open issue for new buildings made of carbon-reinforced concrete is the definition or specification of a ductility criterion. Since the pure carbon reinforcement has a linear-elastic material behavior, the valid ductility criteria from reinforced concrete construction cannot be transferred to carbon-reinforced concrete. This problem is to be dealt with within the scope of the diploma thesis.

Contact person:
Prof. Dr.-Ing. Alexander Schumann
CARBOCON GmbH, Ammonstraße 72, 01067 Dresden
0351 4820 5511

C - 7 Bond behavior of impregnated textile reinforcements in CRC

Full title: Presentation and comparison of different methods for characterizing the composite behavior of impregnated textile reinforcements in composite carbon-reinforced concrete

The bond behavior of the composite material carbon-reinforced concrete can be described by means of the bond stress-slip relationship (Verbundspannung-Schlupf-Beziehung, VSB). This relationship is used in practice to calculate end-anchorage and lap lengths. The bond between the textile reinforcement and the concrete is based on different mechanisms such as positive, adhesive and frictional connection.

In this work, different methods for characterizing the composite behavior of carbon-reinforced concrete will be compared both theoretically and experimentally. The methods already used in the scientific community to determine the VSB are to be compared and their respective approaches to describing the bonding mechanisms are to be presented.

First of all, a literature review is to be carried out with regard to the existing methods for describing the bond behavior of carbon-reinforced concrete. National and international research findings are to be taken into account. Subsequently, the main differences will be pointed out and discussed scientifically. The experimental test setups for determining the VSB are to be compared with each other both theoretically and practically. For this purpose, different pull-out tests will be carried out on different textiles.

Finally, a suitable test setup is to be derived on the basis of the findings obtained.

Contact person:
Prof. Dr.-Ing. Alexander Schumann
CARBOCON GmbH, Ammonstraße 72, 01067 Dresden
0351 4820 5511