Papers by Andrzej Garbacz
MATEC Web of Conferences
In concrete repair specifications, the required moisture condition of the substrate, which can pl... more In concrete repair specifications, the required moisture condition of the substrate, which can play an important role for bond development, and, ultimately, on the long-term repair / overlay durability, is generally ill-defined and addressed without due consideration to the given substrate characteristics. The standard specification, if any, is to require saturated surface dry (SSD) condition of the substrate prior to application of cementitious repair materials, which is theoretically achieved after saturating the substrate and then letting the surface just start to dry out. This does provide an intuitive solution founded on rational considerations, but it has never really been precisely defined, measured, nor validated. The influence of substrate surface moisture on the bond between the existing concrete and the new repair material is an issue of significant importance. This paper revisits the question, in light of results from a project designed to develop guidelines for moisture...
Materials
A combination of multiple nondestructive testing (NDT) methods speeds up the assessment of concre... more A combination of multiple nondestructive testing (NDT) methods speeds up the assessment of concrete and increases the precision. This is why the UIR-Scanner was developed at Warsaw University of Technology. The scanner uses an Impact-Echo (IE) method with a unique arrangement of multiple transducers. This paper presents the development of the IE module using numerical models validated with experimental testing. It was found that rectangular arrangement of four transducers with the impactor in the middle is optimal for quick scanning of area for faults and discontinuities, changing the method from punctual to volumetric. A numerical study of void detectability depending on its position with respect to the IE module is discussed as well. After confirmation of the findings of models using experimental tests, the module was implemented into the scanner.
Architecture Civil Engineering Environment, 2010
A b s t r a c t Polymer-cement composites (PCC) are commonly considered as new and innovative bui... more 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 jes...
Research projects performed at the University of Liege, Laval University and the Warsaw Universit... more Research projects performed at the University of Liege, Laval University and the Warsaw University of Technology have pointed out the importance of taking care about the surface roughness of concrete substrate with regards to the adhesion of repair materials. This paper wants to make a State-of-Art on this specific problem: surfometry methods, interface analysis, adhesion measurements, ...etc are presented, interpreted and compared. Surfology, which is a more wide concept, contributes to understand what will make the contact effective or not, and allow interactions of variable intensities between the materials. Different scales of observation – micro to macro are needed to exactly represent what happens when materials are put into contact. – for instance the profile arithmetic mean and the flatness coefficient are particularly discriminating both for the shape of valleys and peaks, as well as for their amplitude and frequency. The selected characterization techniques were compared f...
Polymers, 2021
This paper presents fiber-reinforced polymer composites which were modified by fibers hybridizati... more This paper presents fiber-reinforced polymer composites which were modified by fibers hybridization as well as matrix nanomodifiaction with nanosilica. The article analyzed the nanosilica matrix modification and basalt-carbon hybridization’s effect on key properties of composites use as the main reinforcement in concrete structures. The comparative analysis was based on results of bars strength parameters determined in a shear test with the ASTM standard. The tests were performed for three bar diameters at room temperature and pre-heated FRP composites at 80 °C and 200 °C for 2 h with the aim of verifying the influence of the fiber hybridization-basalt-carbon fiber-reinforced polymer (HFRP) bars and the effect of nanosilica modification of the epoxy matrix (nHFRP). The test results were also compared with results of the shear test carried out after the bars were heated to 80 °C for 30 min in order to verify and evaluate the effect of the heating time. These types of tests are releva...
Budownictwo i Architektura, 2020
One of the main concerns that limit the widespread use of Fibre-Reinforced Polymers (FRP) bars as... more One of the main concerns that limit the widespread use of Fibre-Reinforced Polymers (FRP) bars as internal reinforcement for reinforced concrete (RC) structures is their relatively unexplored response to elevated temperatures. The behaviour of FRP reinforcement at elevated temperature as well as their post-fire behaviour can be different from conventional reinforcement and depends on the properties of the constituents of the bars. Therefore, the fire resistance of FRP-RC structures is an important issue that needs careful investigation before FRP reinforcement can be implemented in RC structures. The experimental results for full-scale FRP-RC beams subjected to specific fire action were presented and discussed in this paper. The specimens were exposed to heat in the mid-section from below (tension zone) and from the sides. As one of the main aims was to examine the influence of different reinforcement configurations, the testing was made for concrete beams reinforced with three diff...
Materials, 2020
The article discusses one of the methods of dielectric constant determination in a continuous way... more The article discusses one of the methods of dielectric constant determination in a continuous way, which is the determination of its value based on the amplitude of the wave reflected from the surface. Based on tests performed on model asphalt slabs, it was presented how the value of the dielectric constant changes depending on the atmospheric conditions of the measured surface (dry, covered with water film, covered with ice, covered with snow, covered with de-icing salt). Coefficients correcting dielectric constants of hot mix asphalt (HMA) determined in various surface atmospheric conditions were introduced. It was proposed to determine the atmospheric conditions of the pavement with the use of wavelet analysis in order to choose the proper dielectric constant correction coefficient and therefore improve the accuracy of the pavement layer thickness estimation based on the ground penetrating radar (GPR) method.
Materials, 2020
This paper presents research dealing with the evaluation of the efficiency of concrete repairs wi... more This paper presents research dealing with the evaluation of the efficiency of concrete repairs with polymer-cement mortars made at low temperatures with two types of cement and modified by copolymer acrylic-styrene. The low temperature used for the tests, of about 8 °C, is representative for Central Europe, and was established based on the analysis of mean temperatures in Poland during the last 45 years. A comparative analysis of the basic properties of the mortar tested, important from the point of view of repair efficiency, was performed, i.e., flexural and compressive strength, modulus of elasticity, adhesion to the substrate, and porosity for mortars applied and cured at 8 °C and 21°, respectively. The studies were conducted using standard methods and supported with an assessment of microscopic images (1000× magnification). It was shown that when the temperature of polymer-cement composite (PCC) mortar application is lowered to values slightly exceeding the minimum film-forming ...
IOP Conference Series: Materials Science and Engineering, 2019
Przegląd Spawalnictwa - Welding Technology Review, 2015
Archives of Civil Engineering, 2019
The paper describes the recent developments of Hybrid Fibre-Reinforced Polymer (HFRP) and nano-Hy... more The paper describes the recent developments of Hybrid Fibre-Reinforced Polymer (HFRP) and nano-Hybrid Fibre-Reinforced Polymer (nHFRP) bars. Hybridization of less expensive basalt fibres with carbon fibres leads to more sustainable alternative to Basalt-FRP (BFRP) bars and more economically-efficient alternative to Carbon-FRP (CFRP) bars. The New-Developed HFRP bars were subjected to tensile axial loading to investigate its structural behaviour. The effect of hybridization on tensile properties of HFRP bars was verified experimentally by comparing the results of tensile test of HFRP bars with non-hybrid BFRP bars. It is worth to mention that the difference in obtained strength characteristics between analytical and numerical considerations was very small, however the obtained results were much higher than results obtained experimentally. Authors suggested that lower results obtained experimentally can be explained by imperfect interphase development and therefore attempted to improv...
MATEC Web of Conferences, 2018
The main factors determining the choice of fiber-reinforced polymer (FRP) materials are the inten... more The main factors determining the choice of fiber-reinforced polymer (FRP) materials are the intended use of the designed structure and the environmental conditions in which it will be located. Currently, the FRP-based materials have a variety of applications in the construction industry, from the secondary structural elements of buildings, to a complicated designs, where the only FRPs were used. The advances in FRP technology have spurred interest in introducing innovative hybrid fiber-reinforced polymer (HFRP), which potentially can be used as reinforcing/enhancing material. This paper describes the investigation on newly-developed hybrid fiber-reinforced polymer HFRP bars, which were created by modification of basalt fiber-reinforced polymer BFRP bars in terms of physical substituting of the certain amount of basalt fibers by the part of carbon fibers. Modification is aimed at achieving of better properties in obtained material and simultaneously ensuring cost-effectiveness concep...
Archives of Civil Engineering, 2018
The article presents the results of the research on thermal actions on the materials occurring in... more The article presents the results of the research on thermal actions on the materials occurring in the cross section along the depth of the bridge deck and bituminous pavement during its construction. The impulse to curried out the research was the need to explain the causes of the blistering of bituminous waterproofing membranes and asphalt pavements often observed on the bridge decks. The paper presents the examples of such failures and the analyses of possible mechanisms of the phenomenon. Research indicates a significant influence of all technological processes on the temperature of materials in the cross section as well as daily temperature changes. The probability of initiation of reactions between concrete components with gaseous products has been confirmed in such conditions. The susceptibility of bituminous materials to gas emission and blistering is the subject of a separate study. The research was part of a research project carried out under the contract INNOTECHK3/IN3/50/...
Periodica Polytechnica Civil Engineering, 2019
The paper describes a new method for assessing the impact of increasing static strength due to cy... more The paper describes a new method for assessing the impact of increasing static strength due to cyclic loading on the fatigue life of various materials and provides a mathematical description. Experimental results available in the literature were used. A generalized concept of unit fatigue damage was used to produce a simple hypothesis defining fatigue life as a function of load history. The method is mainly devoted to analysis of semi-rigid asphalt pavements but can also be applied to other engineering materials. Two sample calculations were conducted which drew on the results of fatigue tests under variable loading: one concerns cement-treated soils used as base layers for road pavements and the second describes the fatigue problem of a beam rear axle made of TL1114.
MATEC Web of Conferences, 2016
Advanced Materials Research, 2015
The construction industry is responsible for high energy and raw materials consumption. Thus, it ... more The construction industry is responsible for high energy and raw materials consumption. Thus, it is important to minimize the high energy consumption by taking advantage of renewable energy sources and reusing industrial waste, decreasing the extraction of natural materials. The mortars with incorporation of phase change materials (PCM) have the ability to regulate the temperature inside buildings, contributing to the thermal comfort and reduction of the use of heating and cooling equipment, using only the energy supplied by the sun. The simultaneous incorporation of PCM and fly ash (FA) can reduce the energetic consumption and the amount of materials landfilled. However, the addition of these materials in mortars modifies its characteristics. The main purpose of this study was the production and characterization in the fresh and hardened state of mortars with incorporation of different contents of PCM and FA. The binders studied were aerial lime, hydraulic lime, gypsum and cement. ...
4th International Conference on Concrete Repair, Rehabilitation and Retrofitting (ICCRRR-4), 5-7 October 2015, Leipzig, Germany, 2015
2nd International RILEM Symposium on Advances in Concrete through Science and Engineering, 2006
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Papers by Andrzej Garbacz