Ph.D. Tezi Görüntüleme

Student: Ahmet ÇAVDAR
Supervisor: Asst. Prof. Dr. Şükrü YETKİN
Department: İnşaat Mühendisliği
Institution: Graduate School of Natural and Applied Sciences
University: Karadeniz Technical University, Turkey
Title of the Thesis: Investigation On The Durability Aspect Of The Cement Paste Samples Having Different Pozzolanic Composition And Matrix Subjected To The Mediums Containing Sulfate And Or Abrasive Effects
Level: Ph.D.
Acceptance Date: 23/6/2008
Number of Pages: 235
Registration Number: Di639
Summary:

       Concrete consequently cement mortars aspect; the durability phenomena gain sensitivity recently as important as at least mechanical properties. Durability phenomena can be described as concrete’s resistant against destructive influences of the medium containing acid, sulfate and/or various chemicals and mechanical effects like abrasion. Most of the studies realized to improve concrete’s these properties discussing these effect one by one. However, concrete can be subjected to two or more of these effects simultaneously.

In this study, the mortars produced with seven different cements and varied with air-entraining agent were firstly subjected to influence of sulfate and abrasive effects separately. Later, these two effects applied to the cement mortars together. The study, the conclusions of the examples realized with the samples cured for seven different periods throughout one year discussed in, is supported by thin section and XRPD investigations besides the basic tests as compression, flexure and abrasion.

       In the first chapter of this study consisting of four chapters, it is introduced shortly to subjects of concrete and durability and the point arrived about this subject is explained in the light of references. Material properties and experiments are given in second chapter and in the third chapter, the findings are discussed. After important conclusions and suggestions are emphasized in the last chapter, the study is completed.

If the most important findings obtained from the study are summarized; it is seen that compact cement matrix is more effective factor against both sulfate and abrasive effects than mineral additives. The samples that do not contain mineral additives and have more porous matrix were particularly subjected to larger scale deterioration via sulfate influence. In case of pozzolanic material content is more than 25% by mass, it does not provide important contribution on cement paste against detrimental effects of sulfate. The pastes subjected to coupled (sulfate and abrasive) effects show less durability if compared with the ones cured in water and later abraded

      Keywords: Durability, Sulfate Attack, Abrasion, Coupled Effect, Cement, Mineral Additives, Petrographic

Investigation, XRPD.