Ocena wpływu cyklicznego obciążenia na wytrzymałość statyczną mieszanek związanych cementem stosowanych w konstrukcjach nawierzchni drogowych

Karol Brzeziński

Abstract

The subject of the dissertation is evaluation of the cyclic loading influence on the static strength of the cement treated mixtures used in the construction of road pavements. Cyclic loading causes the internal changes in the structure and microstructure of the material, which manifests as fatigue when the phenomenological approach is applied. This phenomenon is usually described using the fatigue hypotheses, which allows to estimate the number of repeated load required to destroy the material. Nevertheless, it is strongly associated with the change of static strength. Evaluation of changes in static strength under cyclic load requires a different testing procedure than fatigue tests, but allows to obtain additional information about the nature of changes occurring in the material. The tests were preceded with the review and analysis of available Polish and foreign publications, mostly related to the fatigue life estimation and mechanistic design of road pavements. Moreover papers describing the effect of cyclic loading on the internal changes observed in case of various materials were analyzed. The dissertation presents the author's cumulative fatigue damage hypothesis, which paved the way to explore the relationship between cyclic loads and static strength of cement treated mixtures. The main part of the study focuses on the evaluation of the cyclic loading influence on the static strength of the cement treated mixtures. The low cycle loads were carried out (up to 2000 cycles). Thanks to the appropriate interpretation of the results of fatigue tests, it was possible to significantly extend the range of data for analysis. The reversal of a certain fatigue hypothesis, allowed to use the literature research results in order to calibrate the proposed model, which describes the phenomenon of changes in static strength under cyclic loading. The calibrated model allows to obtain the static strength of the mixture on the basis of the number of cycles and the level of the material effort. This model can be directly used as a stand-alone fatigue criterion. It can also be part of the cumulative fatigue damage hypothesis proposed earlier by the author of the thesis. The numerical analysis using Finite Element Method (FEM) was carried out as a part of the thesis. The aim of the analysis was to simulate the static strength test. The simulations take into account the structural changes that could potentially explain the observed phenomena. The summary of the thesis contains conclusions formulated based on the analytical, experimental and numerical results. Furthermore, the potential application of the obtained results and the directions of further research were indicated. The dissertation was supplemented by three annexes, containing detailed results of the research and significant portions of the FEM model source code, programmed in ABAQUS®. The last annex describes the work to be undertaken in the analysis fields of displacements and crack detection using digital image correlation, which could be a contribution to the further research.
Diploma typeDoctor of Philosophy
Author Karol Brzeziński (FCE / IRB)
Karol Brzeziński,,
- The Institute of Roads and Bridges
Title in PolishOcena wpływu cyklicznego obciążenia na wytrzymałość statyczną mieszanek związanych cementem stosowanych w konstrukcjach nawierzchni drogowych
Languagepl polski
Certifying UnitFaculty of Civil Engineering (FCE)
Disciplineconstruction / (technology domain) / (technological sciences)
Start date17-06-2015
Defense Date05-07-2017
End date12-07-2017
Supervisor Artur Zbiciak (FCE / IRB)
Artur Zbiciak,,
- The Institute of Roads and Bridges

External reviewers Mirosław Graczyk - Instytut Badawczy Dróg i Mostów
Mirosław Graczyk,,
-

Piotr Mackiewicz - Zakład Dróg i Lotnisk (ZDL) [Wydział Budownictwa Lądowego i Wodnego (WBLiW)]
Piotr Mackiewicz,,
-
Pages139
Keywords in Englishroad pavements, fatigue life, cyclic loading, cement-bond mixtures, fatigue hypothesis, mechanistic-empirical design
Abstract in EnglishThe subject of the dissertation is evaluation of the cyclic loading influence on the static strength of the cement treated mixtures used in the construction of road pavements. Cyclic loading causes the internal changes in the structure and microstructure of the material, which manifests as fatigue when the phenomenological approach is applied. This phenomenon is usually described using the fatigue hypotheses, which allows to estimate the number of repeated load required to destroy the material. Nevertheless, it is strongly associated with the change of static strength. Evaluation of changes in static strength under cyclic load requires a different testing procedure than fatigue tests, but allows to obtain additional information about the nature of changes occurring in the material. The tests were preceded with the review and analysis of available Polish and foreign publications, mostly related to the fatigue life estimation and mechanistic design of road pavements. Moreover papers describing the effect of cyclic loading on the internal changes observed in case of various materials were analyzed. The dissertation presents the author's cumulative fatigue damage hypothesis, which paved the way to explore the relationship between cyclic loads and static strength of cement treated mixtures. The main part of the study focuses on the evaluation of the cyclic loading influence on the static strength of the cement treated mixtures. The low cycle loads were carried out (up to 2000 cycles). Thanks to the appropriate interpretation of the results of fatigue tests, it was possible to significantly extend the range of data for analysis. The reversal of a certain fatigue hypothesis, allowed to use the literature research results in order to calibrate the proposed model, which describes the phenomenon of changes in static strength under cyclic loading. The calibrated model allows to obtain the static strength of the mixture on the basis of the number of cycles and the level of the material effort. This model can be directly used as a stand-alone fatigue criterion. It can also be part of the cumulative fatigue damage hypothesis proposed earlier by the author of the thesis. The numerical analysis using Finite Element Method (FEM) was carried out as a part of the thesis. The aim of the analysis was to simulate the static strength test. The simulations take into account the structural changes that could potentially explain the observed phenomena. The summary of the thesis contains conclusions formulated based on the analytical, experimental and numerical results. Furthermore, the potential application of the obtained results and the directions of further research were indicated. The dissertation was supplemented by three annexes, containing detailed results of the research and significant portions of the FEM model source code, programmed in ABAQUS®. The last annex describes the work to be undertaken in the analysis fields of displacements and crack detection using digital image correlation, which could be a contribution to the further research.
Thesis file
Dissertation.pdf 7.99 MB

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