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Fazhou Wang - One of the best experts on this subject based on the ideXlab platform.

  • Improvement of the FRP sheet bonded to Concrete Substrate by silane coupling agent
    Journal of Wuhan University of Technology-materials Science Edition, 2018
    Co-Authors: Fazhou Wang, Li Ming, Jun Wang
    Abstract:

    We experimentally studied the fine lightweight aggregate with the particle size range of 3.15-4.75 mm used as functional bridge between FRP sheet and Concrete Substrate. However, problems would appear and how to deal with the interfacial transition zone (ITZ) and make it stronger is the key point for this concept. Considering that silane coupling agent (SCA) can provide a better bond on a silicon-containing material surface, it was introduced as a modifying material to further improve the bond quality of the ITZ between lightweight aggregate and cement paste. Results indicated that the water absorptivity of lightweight aggregate can be controlled by SCA solutions, and the pull-off bond strength, mechanical strength, and microhardness were increased, which was attributed to the optimized microstructure under the condition of an appropriate concentration of SCA.

  • bond behavior of roughing frp sheet bonded to Concrete Substrate
    Construction and Building Materials, 2014
    Co-Authors: Fazhou Wang
    Abstract:

    Abstract With the thickness of 1–2 mm made of FRP, a thin Concrete scaleboard which can be used accompanying with Concrete pouring was presented with the aim to improve the durability of Concrete, in which the use of porous lightweight aggregate as roughing coating during FRP sheet producing was innovated to strengthen the bond performance between FRP sheet and Concrete. Results indicated that lightweight aggregate with a particle size distribution from 3.15 to 4.75 mm showed nice bond performance, the average bond strength was 2.17 MPa. Bond strength was determined by mechanical interlocking and interfacial structure, and a bond equation was established.

Gang Wu - One of the best experts on this subject based on the ideXlab platform.

  • bond behavior between basalt fiber reinforced polymer sheet and Concrete Substrate under the coupled effects of freeze thaw cycling and sustained load
    Journal of Composites for Construction, 2013
    Co-Authors: Zhishen Wu, R Seracino, Gang Wu
    Abstract:

    AbstractThis paper presents an experimental investigation on the bond behavior between basalt fiber–reinforced polymer (BFRP) sheet and Concrete Substrate under the coupled effects of freeze-thaw cycling and sustained load. Test variables were freeze-thaw cycles, level of sustained load, and adhesive type. Double-lap shear specimens were used in the tests, and a specially designed reaction-loading system was used to apply the sustained load during freeze-thaw cycles. Specimens with or without sustained load were exposed to up to 300 freeze-thaw cycles. A modified epoxy resin, made by adding a toughening agent to the original epoxy resin, was used in the test to study the effect of adhesive type on the durability of the BFRP–Concrete interface. Coupon tests were also conducted to determine the freeze-thaw resistance of the constituent materials of the BFRP–Concrete interface. After exposure, double-lap shear tests were carried out to investigate the residual bond capacity of the BFRP–Concrete interface. Di...

Andrzej Garbacz - One of the best experts on this subject based on the ideXlab platform.

  • Near-to-Surface properties affecting bond strength in Concrete repair
    Cement & Concrete Composites, 2014
    Co-Authors: Luc Courard, Tomasz Piotrowski, Andrzej Garbacz
    Abstract:

    Abstract One of the main processes for repairing Concrete structures is patch repair. Efficiency and durability of a repaired system depends on the bond between Concrete Substrate and repair material. By increasing the surface roughness, the surface treatment of Concrete Substrate can promote mechanical interlocking that is one of the basic mechanisms of adhesion. Nevertheless, some problems may arise from “co-lateral” effects of the treatment, especially due to the development of microcracks inside the Substrate. In the presented paper, the effect of Concrete Substrate surface preparation has been characterized by roughness measurement, description of microcracking in the near-to-surface layer and a pull-off cohesion test. After repair, pull-off bond strength has been evaluated. It is concluded that selection of a suitable surface treatment technique should be preceded by the analysis of its aggressiveness in relation to the Concrete Substrate strength. A procedure for bond strength estimation using multiple regression approach, based on parameters describing surface quality really generated from various roughening techniques, is then proposed.

  • Patch repair: compatibility issues
    2014
    Co-Authors: Andrzej Garbacz, Luc Courard, Benoît Bissonnette, W. Głodkowska
    Abstract:

    Repair of any Concrete structure results in formation of complex, at least two-component repair systems. Compatibility approach is treated as a basic requirement during selection of repair material. Recently, the understanding for compatibility requirements in repair systems approach is demonstrated in many papers. The aim of this paper is analyzing the compatibility between repair materials and Concrete Substrate in the case of patch repair. The compatibility issues were discussed in light of the various requirements which determine the mathematical space of loads, including chemical, mechanical and other physical (mainly thermal) loads. N-dimensional compatibility space is created, taking into account selected patch material control parameters. The requirements for good compatibility between repair material and Concrete Substrate can be formulated by using mathematical inequalities, where the variables are the material control parameters. The effects of properties of the both repair material and Concrete Substrate were analyzed using computer system ANCOMP developed at Warsaw University of Technology. Usability of this approach was demonstrated using selected case study as an example. created taking into account selected material control parameters. Czarnecki et al. (1992) and Glodkowska (1994) have formulated three main compatibility models for: injection, patch repair and protective coating. Every model consists of a number of inequalities defining good compatibility requirements for selected repair systems. The material parameters proposed for evaluation of material compatibility for patch repair are presented in Table 1. Table 1. Properties of repair material and Concrete Substrate used in a compatibility model of patch repair Material property: Repair material Concrete Substrate tensile strength [MPa] ftp ftc modulus of elasticity (in tension) [MPa] Etp Etc modulus of elasticity (in compression) [MPa] Ecp Ecc Coeff. of thermal expansion [1/K] Tp Tc Coeff. of thermal conductivity [W/mK] Tp Tc elongation at break [mm/mm] tp curing shrinkage [mm/mm] s Poisson coefficient [-] p layer thickness [mm] hp interlayer adhesion [MPa] fAo pi/(pi+1) Max. crack width at coating failure [mm] w max crack width [mm] wd Crack width change [mm] w Adhesion to the Substrate in shear [MPa] fAs Adhesion to the Substrate in tensile [MPa] fAo Temperature gradient during service [K] T The requirements for good compatibility between repair material and Concrete Substrate are formulated using mathematical inequalities (see Table 2), where the variables are the material control parameters. The range of values for these parameters should be defined for the given repair type and the compatibility should be calculated over the whole domain of variability of the material control parameters. The range of material parameter values usually corresponds to that of existing repair materials. However, the compatibility space can be also determined for a “virtual” repair material, which may not exist yet. It means that the compatibility approach can be also used for designing new materials that result in a repair that has a proper equilibrium among reliability, durability and economy. Table 2. Compatibility requirements for patch repair Compatibility requirements Remarks ) ( ) ( o tcm o tp t f t f 

  • Stress wave propagation throughout an interface: PCC composites - Concrete Substrate in repair system
    Architecture Civil Engineering Environment, 2010
    Co-Authors: Andrzej Garbacz
    Abstract:

    A b s t r a c t Polymer-cement composites (PCC) are commonly considered as new and innovative building materials, especially useful for repair and surface protection of Concrete structures. According to new European standard EN1504 and other technical guidelines, non-destructive methods, mainly based on a propagation of stress waves, are recommended for quality control of repair efficiency. The aim of this paper is the analysis of effect of PCC microstructure and quality of interface on a stress wave propagation in a repair system: PCC – Concrete Substrate tested with impact-echo and ultrasonic methods. S t r e s z c z e n i e Kompozyty polimerowo-cementowe (PCC) są uwazane za nowe i innowacyjne materialy budowlane, szczegolnie przydatne do napraw i ochrony powierzchniowej konstrukcji betonowych. Norma EN-1504, a takze inne dokumenty techniczne zale cają stosowanie metod nieniszczących, w szczegolności wykorzystujących fale sprezyste, do kontroli skuteczności napraw. Celem pracy jest analiza wplywu na propagacje fali sprezystej mikrostruktury PCC oraz jakości zespolenia w ukladzie naprawczym: PCC – podloze betonowe badanym metodami impact-echo i ultradźwiekowymi.

  • on the ultrasonic assessment of adhesion between polymer coating and Concrete Substrate
    Cement & Concrete Composites, 2006
    Co-Authors: L Czarnecki, Andrzej Garbacz, Mikolaj Krystosiak
    Abstract:

    In this paper, the ultrasonic methods were used to assess an adhesion between polymer composite and Concrete Substrate. The usability of indirect (surface) ultrasonic methods was evaluated on the example of commercial polymer coating. The relationships between pull-off strength and propagation of ultrasonic wave were established and analyzed. The effect of chemical composition and thickness of PC system was discussed. The results confirmed usefulness of indirect ultrasonic method for non-destructive mapping of adhesion between polymer composite and Concrete Substrate.

  • Effect of Concrete Substrate texture on the adhesion properties of PCC repair mortar
    2006
    Co-Authors: Luc Courard, Andrzej Garbacz, D. Schwall, Tomasz Piotrowski
    Abstract:

    The study of adhesion of repair materials on Concrete structures implies a good knowledge of the influence of Concrete surface characteristics. A large research project has been realized with regards to the influence of Concrete Substrate strength and preparation technique efficiency. Three types of Concretes and four types of surface preparation have been combined in order to obtain twelve different Concrete slabs. They have been characterized according different destructive and non destructive techniques: Schmidt hammer, compressive strength, superficial cohesion (pull-off tests), Impact Echo measurements and cracking quantification (microscopical observations). Finally, a polymer cement Concrete mortar has been applied and adhesion has been evaluated by means of pulloff and laboratory tensile tests. The relationships between parameters describing surface quality (roughness, cracking), adhesion strength and stress wave propagation have been analysed.

Łukasz Sadowski - One of the best experts on this subject based on the ideXlab platform.

  • The influence of texturing of the surface of Concrete Substrate on its adhesion to cement mortar overlay
    Journal of Adhesion, 2019
    Co-Authors: Łukasz Sadowski, Kamil Krzywiński, M. Michoń
    Abstract:

    ABSTRACTThis paper describes a study conducted to evaluate the influence of texturing of the surface of Concrete Substrate on the pull-off adhesion (fb) of Concrete mortar overlay. Moreover, the co...

  • Micromechanical properties within the interphase between heterogeneous layers made of cementitious composites
    Construction and Building Materials, 2019
    Co-Authors: Łukasz Sadowski, Andrzej Żak, Damian Stefaniuk, Konrad J. Krakowiak
    Abstract:

    Abstract The article presents the evaluation of the micromechanical properties of the material within the interphase between heterogeneous layers made of cementitious composites. For this purpose, two different cementitious composites were selected in order to create a two-layer heterogeneous system. Cement mortar was applied as the overlay and Concrete was used as the Substrate. To treat the surface of the Concrete Substrate, four different methods, which are the most commonly used in the industry, were applied: patch grabbing of the surface of the Substrate directly after casting (T1), casting against the steel formwork (T2), mechanical grinding (T3) and shot-blasting (T4). Mechanical properties were evaluated at micro-scale using the nanoindentation technique. In particular, the indentation modulus and hardness profiles in the vicinity of the interphase between the overlay and Concrete Substrate were assessed. It is shown that the micromechanical properties of the cementitious composite within the interphase change and depend on the selected surface treatment method. The results indicate a significant change of the indentation modulus and hardness within the interphase region between the overlay and Concrete Substrate with an approximate width of 150 µm. To support these observation, the back-scattered electron images of the interphase, gained using scanning electron microscopy, are presented.

  • The Effect of Texturing of the Surface of Concrete Substrate on the Pull-Off Strength of Epoxy Resin Coating
    THE Coatings, 2019
    Co-Authors: Kamil Krzywiński, Łukasz Sadowski
    Abstract:

    This paper describes a study conducted to evaluate the effect of texturing of the surface of Concrete Substrate on the pull-off strength (fb) of epoxy resin coating. The paper investigates a total of seventeen types of textures: after grooving, imprinting, patch grabbing and brushing. The texture of the surface of the Concrete Substrate was prepared during the first 15 min after pouring fresh Concrete into molds. The epoxy resin coating was laid after 28 days on hardened Concrete Substrates. To investigate the pull-off strength of the epoxy resin coating to the Concrete Substrate, the pull-off method was used. The results were compared with the results obtained for a sample prepared by grinding, normative minimal pull-off strength values and the values declared by the manufacturer. During this study twelve out of fifteen tested samples achieved a pull-off strength higher than 1.50 MPa. It was found that one of the imprinting texturing methods was especially beneficial.

  • Multi-sensor evaluation of the Concrete within the interlayer bond with regard to pull-off adhesion
    Archives of Civil and Mechanical Engineering, 2018
    Co-Authors: Łukasz Sadowski, Andrzej Żak, Jerzy Hoła
    Abstract:

    Abstract The article presents the results of multi-sensor evaluation of the Concrete within the interphase between overlay and existing Substrate with regard to pull-off adhesion. It has been shown that both the effective surface area of the existing Concrete Substrate and the contribution of the exposed aggregate on this Substrate, as a result of Concrete Substrate surface treatment, have a significant impact on pull-off adhesion. The highest adhesion was obtained when the surface of the existing Concrete Substrate was shot-blasted. This method of surface treatment provides both a high coarseness of the surface of the existing Concrete Substrate and considerable exposure of the aggregate on this surface. In order to clarify why this method of surface treatment of existing Concrete Substrate is advantageous with regard to the possibility of obtaining high adhesion, scanning electron microscopy (SEM) was used. SEM microstructural analysis was performed on Concrete cubic specimens taken from the interphase zone between the overlay and existing Concrete Substrate. The results of these studies, including the contact type between the overlay made of cement mortar and the existing Concrete Substrate, are presented in the study.

  • Multi-Scale Evaluation of the Interphase Zone between the Overlay and Concrete Substrate: Methods and Descriptors
    Applied Sciences, 2017
    Co-Authors: Łukasz Sadowski
    Abstract:

    This article presents the problem of examining the interphase zone between the overlay and Concrete Substrate at different levels of observation. The possibility of applying available modern research methods in order to examine the interphase zone with regard to the level of observation is presented. These levels were defined in the paper. Examples of tests that show a possible approach to the examination of the interphase zone are also presented.

Zhishen Wu - One of the best experts on this subject based on the ideXlab platform.

  • bond behavior between basalt fiber reinforced polymer sheet and Concrete Substrate under the coupled effects of freeze thaw cycling and sustained load
    Journal of Composites for Construction, 2013
    Co-Authors: Zhishen Wu, R Seracino, Gang Wu
    Abstract:

    AbstractThis paper presents an experimental investigation on the bond behavior between basalt fiber–reinforced polymer (BFRP) sheet and Concrete Substrate under the coupled effects of freeze-thaw cycling and sustained load. Test variables were freeze-thaw cycles, level of sustained load, and adhesive type. Double-lap shear specimens were used in the tests, and a specially designed reaction-loading system was used to apply the sustained load during freeze-thaw cycles. Specimens with or without sustained load were exposed to up to 300 freeze-thaw cycles. A modified epoxy resin, made by adding a toughening agent to the original epoxy resin, was used in the test to study the effect of adhesive type on the durability of the BFRP–Concrete interface. Coupon tests were also conducted to determine the freeze-thaw resistance of the constituent materials of the BFRP–Concrete interface. After exposure, double-lap shear tests were carried out to investigate the residual bond capacity of the BFRP–Concrete interface. Di...