Yahya Ghasemi Print III pdf

1.4. Approach
Similar to general approach for scientific studies at Luleå University of technology, the 
presented research started by a literature review on available mix design models and the role 
and importance of concrete mix constitutes with the aim of understanding the current 
knowledge on the subject and also to understand the research gaps. The research questions 
were then formulated based on the revealed gaps and neglected aspects of the subject.
Available mix design approaches were divided in to three categories: a) Ideal size distribution 
curve, b) methods that are based on particle packing theory and c) the ones that are based on 
the concept of water demand and water/paste layer theories. The results from laboratory 
measurements of loose packing and calculations based on particle packing models (see 
Section 3.2) were presented and compared in Papers I and II. Papers III and IV deal with the 
principals of defining shape of particles by utilizing specific surface area which directly 
affects the water demand of mixtures. The last two papers were built on comparison of 
measured specific surface area by Blaine test to theoretically calculated specific surface area 
(3.3.2) based on size distribution curve and assumption of spherical shape for the particles. 

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5 
Introduction
1.5. Structure of the thesis
The thesis consists of four main parts: 
-
Theoretical background (Chapters 2 and 3);
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Method (Chapter 4)
-
Results and discussions (Chapters 5 and 6)
-
Conducted studies and published papers (Appendix 1)
The theoretical background consists of an overview on the concepts and theories that were 
utilized within the scope of the thesis which includes: General information on the role of 
aggregates and the influence of their properties on fresh concrete (Chapter 2), an overview of 
mix design approaches particularly particle packing theory and water and paste layer theories 
(Chapter 3) and methods used for conducting measurements and calculations (Chapter 4). The 
theoretical part should be viewed as background containing the definitions and theories that 
are necessary for understanding the approaches taken in the studies in the last part of the 
thesis (Appendix 1).