Abstract/Details

Modelling for the mechanical behavior of cementitious granular materials


1998 1998

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Abstract (summary)

Crack damages due to load application are commonly observed in cementitious granular materials such as concrete, cemented sand, and ceramic materials. Previous analytical models for these types of materials have been developed based on continuum mechanics using a phenomenological approach. However, the theories of continuum mechanics have limitations when used for analyzing fracture mechanism and localized damages at a micro-scale level. Therefore, a microstructural approach is desirable for the analysis of these types of materials.

In this dissertation, a contact law was derived for the inter-particle behavior of two particles connected by a cement binder. Microcracking process within binder was fully taken into account by regarding crack length as a basic damage factor. The binder initially contains small-size cracks which propagate and grow under external loading. As a result the binder is weakened with lower strength in shear and tension. Theory of fracture mechanics was employed to model the propagation and growth of these microcracks for both the shear fracture mode and normal fracture mode. The contact law was then incorporated in the analysis for the overall damage behaviors of cementitious granular material using the statistical micromechanics approach and the distinct element method. These overall damage behaviors include the stress-strain relationship, fracture strength, development of damage zone, and fatigue deformation. The micro-parameters affecting these behaviors are mainly the microcrack length and density, binder toughness, and binder elastic constants.

In the numerical simulations, the cementitious granular materials were represented by 2-D random assemblies of rods bonded by cement binders with preexisting microcracks. Stress-strain relationships were modeled and validated for the uniaxial tension and compression tests, biaxial tension and compression tests, and double cantilever beam test. Force-deflection relationship and fatigue deformation were predicted and validated for the three-point beam tests. The validations tests showed good agreement between the results of numerical simulations and that obtained from available experimental tests. It has been indicated that the proposed models are capable of modeling the mechanical behaviors of cementitious granular materials.

Indexing (details)


Subject
Civil engineering;
Mechanical engineering;
Materials science
Classification
0543: Civil engineering
0548: Mechanical engineering
0794: Materials science
Identifier / keyword
Applied sciences, Cementitious, Fatigue deformation, Fracture mechanics, Granular materials, Microcracking
Title
Modelling for the mechanical behavior of cementitious granular materials
Author
Zhong, Xiaoxiong
Number of pages
222
Publication year
1998
Degree date
1998
School code
0118
Source
DAI-B 59/10, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
9780599073975, 0599073977
Advisor
Chang, Ching S.
University/institution
University of Massachusetts Amherst
University location
United States -- Massachusetts
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
9909235
ProQuest document ID
304439432
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/304439432
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