Iwona Pokorska-Służalec, PhD, DSc

Department of Theory of Continuous Media and Nanostructures (ZTOCiN)
Research Team: Nanomaterials for Applications in Electronics and Biomedicine (ZeBNZEiB)
position: Research Specialist
telephone: (+48) 22 826 12 81 ext.: 454
room: 117
e-mail: ipokorsk

Recent publications
1.Pokorska I., Poński M., Kubissa W., Libura T., Brodecki A., Kowalewski Z.L., Computational Fracture Evolution Analysis of Steel-Fiber-Reinforced Concrete Using Concrete Continuous Damage and Fiber Progressive Models, Materials, ISSN: 1996-1944, DOI: 10.3390/ma16165635, Vol.16, No.5635, pp.1-20, 2023
Abstract:

The process of concrete cracking is a common problem because the first micro-cracks due to the loss of moisture may appear even before the concrete is loaded. The application of fracture mechanics allows for a better understanding of this problem. Steel-fiber-reinforced concrete (SFRC) samples with a notch were subjected to a three-point bending test, and the results for crack energy were used to analyze the concrete’s material properties. In this paper, an experimental and numerical analysis of SFRC with rapid changes in the force (F) crack mouth opening displacement (CMOD) curve (F-CMOD) is presented. In order to obtain the relevant F-CMOD diagrams, three-point bending tests were carried out with non-standard samples with a thickness equal to one-third of the width of standard samples. For analysis purposes, crimped steel fibers were adopted. A probabilistic analysis of the most important parameters describing the material in question, such as peak strength, post-cracking strength, crack mouth opening displacement (CMOD), fracture energy, and the post-cracking deformation modulus, was conducted. The tests and the analysis of their results show that the quasi-static numerical method can be applied to obtain suitable results. However, significant dynamic effects during experiments that influence the F-CMOD curves are hard to reflect well in numerical calculations.

Keywords:

concrete, finite element method (FEM) simulations, steel-fiber-reinforced concrete (SFRC), crack mouth opening displacement (CMOD), steel fibers

Affiliations:
Pokorska I.-IPPT PAN
Poński M.-IPPT PAN
Kubissa W.-Warsaw University of Technology (PL)
Libura T.-IPPT PAN
Brodecki A.-IPPT PAN
Kowalewski Z.L.-IPPT PAN
2.Długosz A., Pokorska I., Jaskulski R., Glinicki M.A., Evolutionary identification method for determining thermophysical parameters of hardening concrete, ARCHIVES OF CIVIL AND MECHANICAL ENGINEERING, ISSN: 1644-9665, DOI: 10.1007/s43452-020-00154-7, Vol.21, pp.35-1-14, 2021
Abstract:

The kinetics of heat transfer in hardening concrete is a key issue in engineering practice for erecting massive concrete structures. Prediction of the temperature fields in early age concrete should allow for proper control of the construction process to minimize temperature gradients and the peak temperatures, which is of particular importance for concrete durability. The paper presents a method of identification of the thermophysical parameters of early age concrete such as the thermal conductivity, the specific heat, and the heat generated by cement hydration in time. Proper numerical models of transient heat conduction problems were formulated by means of finite-element method, including two types of heat losses. The developed experimental–numerical approach included the transient temperature measurements in an isolated tube device and an in-house implementation of an evolutionary algorithm to solve the parameter identification task. Parametric Bezier curves were proposed to model heat source function, which allowed for identifying such function as a smooth curve utilizing a small number of parameters. Numerical identification tasks were solved for experimental data acquired on hardening concrete mixes differing in the type of cement and type of mineral aggregate, demonstrating the effectiveness of the proposed method (the mean-squared error less than 1 °C). The proposed approach allows for the identification of thermophysical parameters of early age concrete even for mixtures containing non-standard components while omitting drawbacks typical for classical optimization methods.

Keywords:

early age concrete, evolutionary algorithm, inverse solution, heat transfer problem, mass concrete, thermal properties

Affiliations:
Długosz A.-Silesian University of Technology (PL)
Pokorska I.-IPPT PAN
Jaskulski R.-IPPT PAN
Glinicki M.A.-IPPT PAN
3.Długosz A., Pokorska I., Glinicki M.A., Jaskulski R., Identification of thermal properties of hardening concrete by means of evolutionary algorithms, COMPUTER ASSISTED METHODS IN ENGINEERING AND SCIENCE, ISSN: 2299-3649, Vol.24, pp.101-111, 2017
Abstract:

In this paper, the evolutionary computation procedures for identifying thermophysical properties in hardening massive concrete structures are presented. The heat of cement hydration, thermal conductivity and specific heat are determined for the purpose of modeling temperature evolution in massive concrete elements. Knowledge about temperature fields is very important due to their link with undesirable thermal stresses that can cause a weakening of structures because of thermal cracking. The proposed method is based on point temperature measurements in a cylindrical mould and the numerical solution of the inverse heat transfer problem by means of the finite element method and evolutionary computation

Keywords:

thermal properties of concrete, inverse heat transfer problem, early age concrete, evolutionary algorithm, FEM

Affiliations:
Długosz A.-Silesian University of Technology (PL)
Pokorska I.-other affiliation
Glinicki M.A.-IPPT PAN
Jaskulski R.-other affiliation

Conference abstracts
1.Pokorska-Służalec I., Nowak Z., Grzywacz H., Wilczewski S., Giersig M., Characterizations of Graphene Reinforced Cement Matrix Composites using Nanoindentation, SolMech 2024, 43rd Solid Mechanics Conference, 2024-09-16/09-18, Wrocław (PL), pp.22, 2024
2.Poński M., Pokorska-Służalec I., Burczyński T., Multiscale Modeling of Concrete with Nano-Ingredients, COMPLAS 2023, XVII International Conference on Computational Plasticity. Fundamentals and Applications, 2023-09-05/09-07, Barcelona (ES), pp.1, 2023
3.Pokorska I., Poński M., Kubissa W., Libura T., Brodecki A., Kowalewski Z., ANALYSIS OF CRACKING EVOLUTION AND FRACTURE ENERGY CHANGE OF STEEL FIBER-REINFORCED CONCRETE, CMM-SolMech 2022, 24th International Conference on Computer Methods in Mechanics; 42nd Solid Mechanics Conference, 2022-09-05/09-08, Świnoujście (PL), No.237, pp.1-1, 2022
4.Pokorska I., Poński M., Kubissa W., Libura T., Brodecki A., Kowalewski Z.L., PROBABILISTIC STUDY ON CRACKING EVOLUTION AND FRACTURE ENERGY CHANGE OF STEEL FIBER-REINFORCED CONCRETE, ICEM, 19th International Conference on Experimental Mechanics, 2022-07-17/07-21, Kraków (PL), pp.363-364, 2022
5.Dlugosz A., Pokorska I., Glinicki M.A., Jaskulski R., Application of evolutionary algorithms in identification of thermal properties of hardening concerte, SolMech 2018, 41st SOLID MECHANICS CONFERENCE, 2018-08-27/08-31, Warszawa (PL), pp.1-2, 2018
6.Długosz A., Pokorska I., Glinicki M.A., Jaskulski R., Evolutionary computation in identification of thermophysical properties of hardening concrete, CMM 2017, 22nd International Conference on Computer Methods in Mechanics, 2017-09-13/09-16, Lublin (PL), pp.1-2, 2017
Abstract:

The evolutionary computation procedures in identification of thermophysical properties of hardening concrete in massive structures are presented. Heat of cement hydration, thermal conductivity and specific heat are determined for purpose of modelling temperature evolution in massive concrete elements. The knowledge of temperature fields is very important due to a link with undesired thermal stresses, which can cause a weakening of the structure because of thermal cracking. The proposed method is based on point temperature measurements in a cylindrical mould and the numerical solution of the inverse heat transfer problem by means of finite element method and evolutionary computation

Keywords:

heat of cement hydration, inverse heat transfer problem, early age concrete, evolutionary algorithm, finite element method, thermophysical properties of concrete

Affiliations:
Długosz A.-Silesian University of Technology (PL)
Pokorska I.-other affiliation
Glinicki M.A.-IPPT PAN
Jaskulski R.-other affiliation
7.Długosz A., Pokorska I., Glinicki M.A., Jaskulski R., Identification of thermal properties of hardening concrete by means of evolutionary algorithms, ECCOMAS - IPM 2017, 4th International Conference on Inverse Problems in Mechanics of Structures and Materials, 2017-05-31/06-02, Rzeszów - Krasiczyn (PL), pp.17-18, 2017

Patents
Filing No./Date
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Protection Area, Applicant Name
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Date of Grant
pdf
443206
2022-12-20
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Giersig M., Wilczewski S., Pokorska-Służalec I., Osial M.
Nanowypełniacz do zaczynów cementowych i betonu na bazie wielowymiarowych nanostruktur węglowych, sposób jego wytwarzania, nanokompozyt, konstrukcja, kompozycja zaczynu zawierająca nanowypełniacz oraz sposoby ich wytwarzania i ich zastosowania
PL, Instytut Podstawowych Problemów Techniki PAN
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