Effect of trass, granulated blast furnace slag and fly ash on delayed ettringite formation

Download
2010
Topbaş, Selim
Properly proportioned, placed and cured concrete can be durable under most conditions. However, deterioration of concrete does occur under certain environments. One of the problems that affect the durability of hardened concrete is delayed ettringite formation (DEF) which is an important problem encountered in precast concrete industry where high temperature curing is applied. Although there had been many researches on DEF, there are still many uncertainties about its chemistry and mechanism. In this study, the effects of partial cement replacement by different mineral admixtures (trass, blast furnace slag and fly ash), SO3/Al2O3 molar ratio and specific surface area of cement on DEF were investigated. For this purpose, 9 groups of control cements were prepared with 3 different specific surface areas and 3 different SO3/Al2O3 molar ratios. Different amounts of mineral admixtures were blended with the control cements. High temperature curing was applied to the cement pastes and the expansions of these pastes were measured periodically for 240 days. v The experimental results obtained were interpreted for a comparative analysis of the effects of the afore-mentioned parameters.

Suggestions

Effect of Fly Ash Fineness on the Activation of Geopolymer Concrete
Aleessa Alam, Burhan; Yaman, İsmail Özgür (2012-10-05)
In the field of construction materials and particularly in concrete, cement is considered as a key element since it generates a strong and durable material through a simple hydration process. However, for many reasons (mainly economic and environmental) researchers are trying to find a new material that could replace cement or at least part of it as a binding agent in concrete. Regarding this issue, cement replacement materials like fly ash and slag have taken the lead during the last few decades. These mat...
Influence of perlite addition on the strength development and thermal stability of calcium aluminate cement mortars
Şengül, Kemal; Erdoğan, Sinan Turhan; Department of Civil Engineering (2018)
Calcium aluminate cement is a special cement that reaches high strength in a short time but suffers a considerable loss of strength due to moisture and temperature-related conversion of metastable calcium aluminum hydrates. The study aimed to produce stratlingite as a stable hydration product to completely stop or reduce this chemical conversion using an inexpensive and abundant silica source. Ground perlite was chosen as the source of silica. Perlite was mixed with calcium aluminate cement in different pro...
Effects of separate and intergrinding on some properties of portland composite cements
Soyluoğlu, Serdar; Tokyay, Mustafa; Department of Cement Engineering (2009)
In the production of cement, to increase the cement/clinker ratio and decrease CO2 emission, the most important alternative is to produce mineral admixture incorporated cements (CEM II-III-IV-V) instead of portland cement (CEM I). These cements are usually produced by intergrinding the portland cement clinker and the mineral admixtures. However, the difference between grindabilities of the different components of such cements may cause significant effects on the particle size distribution and many other pro...
Influence of ground perlite on the hydration and strength development of calcium aluminate cement mortars
Şengül, Kemal; Erdoğan, Sinan Turhan (Elsevier BV, 2021-01-10)
© 2020 Elsevier LtdCalcium aluminate cement (CAC) concretes are desirable owing to their rapid strength development and resistance to high temperatures, sulfates and acids. They suffer two drawbacks, however, high cost and strength loss due to conversion of water-rich hydration products to more stable structures, resulting in a drop in strength. Although its rate is dependent on temperature and moisture, the conversion process is thermodynamically inevitable but can be prevented by adding sufficient quantit...
Effect of mixture proportioning on the strength and mineralogy of magnesium phosphate cements
Bilginer, Baki Aykut; Erdoğan, Sinan Turhan (Elsevier BV, 2021-3)
Magnesium potassium phosphate cement (MKPC) has properties advantageous over ordinary portland cement such as quick setting and rapid strength gain. Although the effect of mixture proportioning on MKPC pastes has been studied, there are conflicting reports on how calcination of magnesia, parameters like magnesium-to-phosphate ratio (M/P) and water-to-binder ratio (W/B), added materials like borax and fly ash, or the addition of sand influence mineralogy and properties like setting and strength. These factor...
Citation Formats
S. Topbaş, “Effect of trass, granulated blast furnace slag and fly ash on delayed ettringite formation,” M.S. - Master of Science, Middle East Technical University, 2010.