Crack-distributing carbon textile reinforced concrete protection layers

Morales Cruz, Cynthia; Orlowsky, Jeanette; Raupach, Michael

doi:10.18154/RWTH-2021-01053

Crack-distributing carbon textile reinforced concrete protection layers = Rissverteilende Textilbeton Schutzschichten mit textiler Carbonbewehrung

Morales Cruz, Cynthia^RWTH*

2020 & 2021

Verantwortlichkeitsangabevorgelegt von Cynthia Morales Cruz

ImpressumAachen : RWTH Aachen University 2020

Umfang1 Online-Ressource (XX, 238 Seiten) : Illustrationen, Diagramme

Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2020

Veröffentlicht auf dem Publikationsserver der RWTH Aachen University 2021

Genehmigende Fakultät
Fak03

Hauptberichter/Gutachter
Raupach, Michael (Thesis advisor)^RWTH* ; Orlowsky, Jeanette (Thesis advisor)

Tag der mündlichen Prüfung/Habilitation
2020-12-22

Online
DOI: 10.18154/RWTH-2021-01053
URL: https://publications.rwth-aachen.de/record/811247/files/811247.pdf

Einrichtungen

Lehrstuhl für Baustoffkunde - Bauwerkserhaltung (311310)

Inhaltliche Beschreibung (Schlagwörter)
TRC (frei) ; carbon textile reinforcement (frei) ; crack-distribution (frei) ; durability (frei) ; repair (frei) ; self-healing (frei) ; textile reinforced concrete (frei)

Thematische Einordnung (Klassifikation)
DDC: 624

Kurzfassung
Crack repair is often necessary to ensure the durability and serviceability of concrete and reinforced concrete structures. Normally, surface protection systems, repair mortar/concrete, or steel-reinforced concrete are used for the surface repair of these components. The latter are often not suitable either for static or space reasons (e.g. underground garages, roofs, cellar walls, or weir systems). The unreinforced systems, on the other hand, lack a durable sealing functionality, especially in the case of cyclically moving cracks and joints due to their limited bond strength and crack-distribution ability. For the permanent repair of water-bearing, cyclically moving cracks and joints, DURTEX layers consisting of Carbon Textile Reinforced Concrete (CTRC) in combination with a de-bonding strip can be used. Such a combination not only enables a fine crack-distribution but also offers a sealing function against water and can be used under the aspect of durability and thus cost-effectiveness. In this thesis, experimental investigations were carried out to fill the gaps in knowledge on the topics of crack-distribution and autogenous self-healing of DURTEX layers for the repair of the cyclic crack opening of concrete and reinforced concrete components. To assess the requirements for crack width limitation, durability, mechanical resistance, water tightness, and long-term stability, the crack-distribution, as well as the bond strength, is investigated in extensive laboratory tests in the context of this thesis. In the first step, a test procedure for the DURTEX layer for both single and combined loads was developed. An essential part was the realistic depiction of the temperature-related crack width changes of the substrate and the exact measurement of the individual crack widths in the CTRC layer. These were analyzed with an optical 3D-measurement system in combination with Digital Image Correlation (DIC)-software. The laboratory tests carried out include the characterization of the design parameters repair mortar/concrete, de-bonding strip, polymer impregnated carbon textile reinforcements (CTRs) as well as performance tests on the composite bodies. Based on the results of the laboratory tests, the relevant parameters are identified and the performance and limits are derived. In general, it was shown that the subsequent surface modification of the epoxy impregnated carbon textile reinforcement (EPI-CTR) consisting of an epoxy coating and sprinkled with quartz sand (EPI+S-CTR) leads to an increase in the adhesive tensile strength perpendicular to the reinforcement plane by at least 35 % compared to the EPI-CTR. At the same time, the crack spacing is reduced to the single roving axis distance of the EPI-CTR, the number of continuous cracks is increased to its maximum (referred to as ideal crack-distribution) and the average crack width is reduced by 33 % up to 50 % in the CTRC perpendicular to the direction of tensile loading. In the context of this thesis, the surface roughness of the CTR, the roving axis distance of the CTR, the reinforcement ratio, the de-bonding width, the bond strength between repair mortar/concrete and CTR as well as between de-bonding strip and repair mortar/concrete perpendicular to the reinforcement plane were identified as decisive factors influencing the crack-distribution in DURTEX layers. It was observed that cracked DURTEX layers with w_(max.) = 0.116 mm, under cyclic loading (initial Δw_op = 0.6 mm) with a 5 m pore and crack water pressure can self-heal themselves leading to water tightness after 14 days.

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