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Dionysios A. Bournas - One of the best experts on this subject based on the ideXlab platform.

  • Out-of-Plane Strengthening of Masonry-Infilled RC Frames with Textile-Reinforced Mortar Jackets
    Journal of Composites for Construction, 2019
    Co-Authors: L. Koutas, Dionysios A. Bournas
    Abstract:

    AbstractThis paper presents an experimental investigation on the use of textile-Reinforced Mortar (TRM) jackets as a means of improving the out-of-plane performance of masonry infill walls in reinf...

  • Bond between textile-Reinforced Mortar (TRM) and concrete substrates: Experimental investigation
    Composites Part B-engineering, 2016
    Co-Authors: Saad M. Raoof, L. Koutas, Dionysios A. Bournas
    Abstract:

    This paper presents an extended experimental study on the bond behaviour between textile-Reinforced Mortar (TRM) and concrete substrates. The parameters examined include: (a) the bond length (from 50 mm to 450 mm); (b) the number of TRM layers (from one to four); (c) the concrete surface preparation (grinding versus sandblasting); (d) the concrete compressive strength (15 MPa or 30 MPa); (e) the textile coating; and (f) the anchorage through wrapping with TRM jackets. For this purpose, a total of 80 specimens were fabricated and tested under double-lap direct shear. It is mainly concluded that: (a) after a certain bond length (between 200 mm and 300 mm for any number of layers) the bond strength marginally increases; (b) by increasing the number of layers the bond capacity increases in a non-proportional way, whereas the failure mode is altered; (c) concrete sandblasting is equivalent to grinding in terms of bond capacity and failure mode; (d) concrete compressive strength has a marginal effect on the bond capacity; (e) the use of coated textiles alters the failure mode and significantly increases the bond strength; and (f) anchorage of TRM through wrapping with TRM jackets substantially increases the ultimate load capacity.

K. Van Breugel - One of the best experts on this subject based on the ideXlab platform.

  • A Preliminary Study on Cathodic Prevention in Reinforced Mortar
    ECS Transactions, 2019
    Co-Authors: Dessi A. Koleva, K. Van Breugel, Johannes M. C. Mol, J.h.w. De Wit
    Abstract:

    This work presents the preliminary tests on the performance of cathodic prevention (CPre) in Reinforced Mortar, subjected to aggressive (10% NaCl environment). Cathodic prevention is an electrochemical technique for minimizing, actually "preventing" any eventual corrosion of the steel bars in Reinforced concrete. Therefore, the main objective of this investigation is to monitor the performance of cathodic prevention (CPre) as an alternative of cathodic protection (CP) i.e. application before corrosion initiation, using low cathodic current densities (1 to 2.5 mA/m2 steel surface). The novelty here is the application of "pulse" cathodic prevention (pulse DC current), rather than the conventional steady DC technique. The paper reports on conventional monitoring (potential mapping and depolarization decay), coupled with visualization of the steel/cement paste interface, using SEM and EDX.

  • Electrochemical and Microstructural Studies in Reinforced Mortar, Modified with Core-Shell Micelles
    ECS Transactions, 2019
    Co-Authors: Dessi A. Koleva, K. Van Breugel, Johannes M. C. Mol, N. Boshkov, J.h.w. De Wit
    Abstract:

    This work reports on monitoring chloride-induced corrosion in Reinforced Mortar specimens, with and without addition of polymeric nano-aggregates in the Mortar mixture. The investigation is a novel approach to control steel corrosion in Reinforced concrete, hereby reporting the preliminary results, related to one of the main objectives: studying the influence of admixed polymer nano-aggregates (in the form of PEO113-b-PS218 core-shell micelles with a very low concentration of 0.006 wt.% per Mortar weight) on the corrosion behavior of the steel reinforcement, compared to reference, micelles-free mixtures.

  • polymeric vesicles for corrosion control in Reinforced Mortar electrochemical behavior steel surface analysis and bulk matrix properties
    Corrosion Science, 2012
    Co-Authors: D.a. Koleva, Petar Petrov, K. Van Breugel
    Abstract:

    This study reports on the corrosion performance of Reinforced Mortar in the presence of polyethylene oxide-b-polystyrene (PEO113-b-PS780) vesicles (both “empty” and Ca-containing vesicles). The electrochemical response and microstructural/morphological observations of the steel reinforcement show that the admixed vesicles, especially the Ca-containing ones, increase the steel corrosion resistance. The responsible mechanisms are initially due to enhanced barrier effects, introduced from the presence of the vesicles themselves and are further (after corrosion initiation) related to calcium release from the Ca-containing vesicles, leading to a repair of the steel surface layer.

  • Corrosion performance of Reinforced Mortar in the presence of polymeric nano-aggregates: Electrochemical behavior, surface analysis, and properties of the steel/cement paste interface
    Journal of Materials Science, 2012
    Co-Authors: Dessi A. Koleva, K. Van Breugel
    Abstract:

    This study reports on the effect of admixed polyethylene oxide-b-polystyrene (PEO113-b-PS70)micelles on corrosion behavior of Reinforced Mortar. The electrochemical measurement shows that the corrosion performance of the reinforcing steel was not significantly improved. However, surface analysis and microstructural investigation at the steel/cement paste interface reveal that the admixed micelles lead to a steel surface layer with enhanced barrier properties in terms of morphology and composition. Therefore, the presence of micelles further minimized and halted the corrosion process, despite the very aggressive, chloride-containing environment of 5% NaCl. The reasons and mechanisms behind the hereby observed corrosion behavior of Reinforced Mortar in the presence of micelles are related to the influence of these nano-aggregates on microstructural properties. These further results in altered water/ion transport and chloride-binding mechanisms in the bulk Mortar matrix and thus steel product layer modifications towards enhanced corrosion resistance.

  • The Influence of Admixed Polymeric Vesicles on Corrosion Performance of Steel in Simulated Pore Solution and/or Reinforced Mortar
    2011
    Co-Authors: D.a. Koleva, K. Van Breugel
    Abstract:

    Introduction: This present study is part of a 2-years project on self-healing of corrosion damages in Reinforced concrete via initially admixed nano materials with tailored properties (micelles and/or vesicles). In the previous investigation, the corrosion behavior of steel in the cement extract or Reinforced Mortar, in the presence of PEO113-b-PS70 micelles was studied [1-3]. In this work, the PEO113-b-PS780 vesicles (both with empty core and CaO core) were admixed in the simulated pore solution or Reinforced Mortar; the corrosion performance of the steel was investigated by the electrochemical measurements (Electrochemical impedance spectroscopy (EIS) and potentio-dynamic polarization (PDP)) and surface analysis (SEM, EDX and XRD). The investigation is ongoing.

A K H Kwan - One of the best experts on this subject based on the ideXlab platform.

  • basalt fibre Reinforced Mortar rheology modelling based on water film thickness and fibre content
    Construction and Building Materials, 2019
    Co-Authors: L G Li, K L Zeng, Y. Ouyang, A K H Kwan
    Abstract:

    Abstract The water film thickness (WFT) has been proven to be the key factor governing the fresh properties of plain cementitious materials with no fibres added. But whether this WFT theory can also be applied to fibre-Reinforced cementitious materials (FRCM) still needs to be further explored. Besides, the fibres added have significant effects on the fresh properties of FRCM. In this study, the combined effects of WFT and fibre content on the workability, flowability, cohesiveness and adhesiveness of basalt fibre-Reinforced Mortar were investigated by testing Mortar mixes with various water/cement ratios and basalt fibre contents. The findings showed that the basalt fibre content has certain effects on the packing density and WFT of the Mortar mix produced. Furthermore, statistical correlation analysis revealed that the WFT and basalt fibre content are the key factors governing the fresh properties of basalt fibre-Reinforced Mortar. Based on such correlation analysis, a series of rheological models for predicting the fresh properties of basalt fibre-Reinforced Mortar and depicting the roles of WFT and basalt fibre content have been developed.

  • Roles of water film thickness and fibre factor in workability of polypropylene fibre Reinforced Mortar
    Cement and Concrete Composites, 2018
    Co-Authors: S.h. Chu, K L Zeng, Jiang Zhu, A K H Kwan
    Abstract:

    Abstract For plain Mortar without fibres, it has been found that its fresh properties are governed mainly by the water film thickness (WFT). For fibre Reinforced Mortar with fibres added, it has been suggested that the effects of the fibres may be evaluated in terms of a fibre factor (FF) combining the fibre volume and aspect ratio together. In two previous studies on the workability of polypropylene (PP) fibre Reinforced Mortar, the combined effects of WFT and fibre volume and the combined effects of WFT and fibre length have been separately studied. Herein, additional tests with both the fibre volume and fibre length varying simultaneously have been carried out to generate more data for evaluating the combined effects of WFT, fibre volume and fibre length. Based on the test results, a new model is developed whereby the workability attributes are each expressed as a single-variable function of the product of a linear function of WFT and an exponential function of FF. By this model, the roles of WFT and FF are revealed and the workability may be estimated for preliminary design of PP fibre Reinforced Mortar.

L. Koutas - One of the best experts on this subject based on the ideXlab platform.

  • Out-of-Plane Strengthening of Masonry-Infilled RC Frames with Textile-Reinforced Mortar Jackets
    Journal of Composites for Construction, 2019
    Co-Authors: L. Koutas, Dionysios A. Bournas
    Abstract:

    AbstractThis paper presents an experimental investigation on the use of textile-Reinforced Mortar (TRM) jackets as a means of improving the out-of-plane performance of masonry infill walls in reinf...

  • Bond between textile-Reinforced Mortar (TRM) and concrete substrates: Experimental investigation
    Composites Part B-engineering, 2016
    Co-Authors: Saad M. Raoof, L. Koutas, Dionysios A. Bournas
    Abstract:

    This paper presents an extended experimental study on the bond behaviour between textile-Reinforced Mortar (TRM) and concrete substrates. The parameters examined include: (a) the bond length (from 50 mm to 450 mm); (b) the number of TRM layers (from one to four); (c) the concrete surface preparation (grinding versus sandblasting); (d) the concrete compressive strength (15 MPa or 30 MPa); (e) the textile coating; and (f) the anchorage through wrapping with TRM jackets. For this purpose, a total of 80 specimens were fabricated and tested under double-lap direct shear. It is mainly concluded that: (a) after a certain bond length (between 200 mm and 300 mm for any number of layers) the bond strength marginally increases; (b) by increasing the number of layers the bond capacity increases in a non-proportional way, whereas the failure mode is altered; (c) concrete sandblasting is equivalent to grinding in terms of bond capacity and failure mode; (d) concrete compressive strength has a marginal effect on the bond capacity; (e) the use of coated textiles alters the failure mode and significantly increases the bond strength; and (f) anchorage of TRM through wrapping with TRM jackets substantially increases the ultimate load capacity.

  • analytical modeling of masonry infilled rc frames retrofitted with textile Reinforced Mortar
    Journal of Composites for Construction, 2015
    Co-Authors: L. Koutas, Thanasis Triantafillou, S N Bousias
    Abstract:

    This paper proposes an analytical approach for modeling the behavior of textile-Reinforced Mortar (TRM)-strengthened masonry-infilled Reinforced-concrete (RC) frames under seismic loading. The model falls into the discrete diagonal-element type and is based on the use of single-strut and single-tie elements to represent the infill panel. It builds on the results of past experimental studies by the writers, in which the application of TRM jacketing was effective for seismic retrofitting of masonry-infilled RC frames. The model is implemented in a nonlinear finite-element code, with the parameters of the diagonal elements being determined from a series of tests on TRM coupons and masonry specimens. The results of the numerical analyses are compared with the experimental data of cyclic tests on 3-story masonry infilled RC frames (as-built and after retrofitting). The model developed in this paper adequately accounts for the TRM-strengthening contribution to the global response of masonry-infilled frames.

Catherine G. Papanicolaou - One of the best experts on this subject based on the ideXlab platform.

  • Role of Mortar Joints in Textile Reinforced Mortar-to-Masonry Bond
    Journal of Composites for Construction, 2020
    Co-Authors: Paraskevi D. Askouni, Catherine G. Papanicolaou
    Abstract:

    Abstract In this paper, the role of masonry joints in the textile Reinforced Mortar (TRM)-to-substrate bond is investigated through an experimental program employing double-lap/double-prism (DL/DP)...

  • textile Reinforced Mortar to masonry bond experimental investigation of bond critical parameters
    Construction and Building Materials, 2019
    Co-Authors: Paraskevi D. Askouni, Catherine G. Papanicolaou
    Abstract:

    Abstract This paper presents an experimental program carried out using double-lap/double-prism shear bond tests in order to assess the effect of: (i) the number of textile layers, (ii) the textile bond width, and (iii) the textile configuration on the bond characteristics of glass fiber Textile Reinforced Mortar (TRM) strips externally bonded on masonry wall prisms. It is concluded that: (i) the effective bond length of the TRM strip increases with increasing number of textile layers, (ii) for the herein employed TRM/substrate combination a bond width effect does exist, and (iii) the textile configuration also plays an important role in bond-related phenomena.