University of South Florida Scholar Commons Graduate Theses and Dissertations Graduate School 4-2-2021 Sulfate Optimization in the Cement-Slag Blended System Based on Calorimetry and Strength Studies Mustafa Fincan University of South Florida Follow this and additional works at: https://scholarcommons.edu/etd Part of the Materials Science and Engineering Commons Scholar Commons Citation Fincan, Mustafa, "Sulfate Optimization in the Cement-Slag Blended System Based on Calorimetry and Strength Studies" (2021). Graduate Theses and Dissertations.edu/etd/8770 This Dissertation is brought to you for free and open access by the Graduate School at Scholar Commons. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Scholar Commons. For more information, please contact scholarcommons@usf.
Sulfate Optimization in the Cement-Slag Blended System Based on Calorimetry and Strength Studies by Mustafa Fincan A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Mechanical Engineering College of Engineering University of South Florida Major Professor: Alex A. Rasim Guldiken, Ph.D Gulfem Ipek Yucelen, Ph. Abdul Malik, Ph. Date of Approval April 2, 2021 Keywords: SO3 Optimization, Supplementary Cementitious Materials (SCMs), Heat of Hydration, Strength, Isothermal Calorimetry Copyright © 2021, Mustafa Fincan Dedication I would like to dedicate my dissertation to my wife and my parents who have always loved, supported, and encouraged me unconditionally.
I am very grateful to have you in my life. Thank you for all your support over the years. Acknowledgments I would like to express my special gratitude and thanks to my thesis advisor Dr. I would also like to thank the members of my committee, Dr.
Rasim Guldiken, Dr. Gulfem Ipek Yucelen, Dr. Sunol, and Dr. Abdul Malik, for their valuable comments, feedback, and suggestions.
I would like to thank all of my friends and colleagues, Dr. Ahmet Colak, Abdullah Ozkan, Dr. Mohammad Khawaja, Dr. Ferhat Karakas, Dr.
Burak Sarsilmaz, Dr. Abdulkadir Fincan, Dr. Mustafa Fincan, Mahmut Erkam Fincan, Mustafa Gecit, Mohammed Al Yaarubi, and members of the USF Construction Materials Research Lab, for their meaningful guidance and encouragement on this dissertation, which has inspired me to improve my work. Finally, I am grateful to everyone for their support, both directly and indirectly, in completing my dissertation.
Table of Contents List of Tables. iii List of Figures. vi Chapter 1: Introduction. 1 Chapter 2: Literature Review .1 General Overview of Portland Cement .2 Ordinary Portland Cement Hydration .1 Calcium Silicates Hydration .2 Tricalcium Aluminate Hydration .3 Tetracalcium Aluminoferrite Hydration .4 Portland Cement Hydration .1 Heat of Hydration .3 Supplementary Cementitious Materials .4 Ground Granulated Blast Furnace Slag .1 Physical, Mineralogical and Chemical Characteristics of Slag .1 Structure and Reactivity of Slags .2 Blended Slag– Cement Hydration .3 Effects of Slag on the Properties of Concrete .1 Bleeding and Segregation .3 Slag and Supplementary Cementitious Materials .4 Fineness and Age.
48 i Chapter 3: Materials and Methodology .1 Chemical oxide composition. 55 Chapter 4: Results and Discussion .1 Determination of Optimum SO3 content.2 Optimization of SO3 Content in the Cement.3 Optimization of SO3 Content in the Slag-Cement Blended System .4 Factors Affecting the Sulfate Demand in the OPC-Slag System.1 The Effect of Alumina (Al2O3) in the Slag .2 The Effect of Cement Particle Size and Fineness .3 The Effect of the Alumina with Mean Particle Size Distribution and Slag Activity.1 Summary and Conclusions. 78 ii List of Tables Table 2.1 Typical ordinary Portland cement oxide composition .2 Typical ordinary Portland cement composition .3 The heat of hydration of pure cement clinker minerals .1 Oxide chemical compositions for cements and calcium sulfate hemihydrate .2 Oxide chemical composition of slags .3 Mineralogical composition of cements .4 Mineralogical composition of the slags .5 Particle size analysis for the slags and cements .6 Mixing procedure for compressive test .1 Optimum SO3 level estimates for Cement A-D .2 Optimum SO3 level estimates on compressive strength and calorimetry test. 67 iii List of Figures Figure 2.1 The heat evolution rate of C3S hydration.2 The heat evolution rate of Portland cement hydration.3 Ternary diagram of the chemical composition of common SCMs and Portland cement .1 Gaussian and 2nd-order polynomial fit for three-day Cement B-Slag1 compressive strength results versus various sulfate levels.2 The heat of hydration flow for 100% Cement A, B, C, and D .3 Gaussian and 2nd-order polynomial fit for Cement D-Slag1 individual specimens compressive strength results versus sulfate level at three-day.4 Gaussian and 2nd-order polynomial fit for Cement D-Slag1 average of specimens compressive strength results versus sulfate level at three-day.5 The Gaussian versus 2nd order polynomial estimate the average strength of the specimens' optimum sulfate level at 1-day and 3-days .6 Heat flow of Cement C and Slag 4 in different sulfate level.7 Comparison of compressive strength and total heat of hydration of one-day Cement A-Slag 1 on the different sulfate levels .8 Comparison of compressive strength and total heat of hydration of three-day Cement A-Slag 1 on the different sulfate levels .9 Optimum sulfate level for the compression strength versus optimum sulfate level for total heat of hydration (HOH).10 The ratio of the cement alumina content to mean particle size of cement plus slag alumina content to mean particle of slag size versus optimum SO3 level.11 Total amount of aluminate and ferrite to mean particle size of cement and the ratio of alumina content of slag to the mean particle size of slags versus optimum SO3 level.
73 v Abstract Optimization of sulfur trioxide (SO3) content is typically conducted for plain cements (OPC-based) paste or mortar systems using compressive strength testing and isothermal calorimetry for quality control. The objective of these procedures is to ensure adequate strength and set properties by controlling the time of occurrence of the aluminate peak by adjusting the SO3 content by incremental addition of sulfate in the form of hemihydrate at three or more levels, at the same time attempting to maximize either strength or heat of hydration at 1 and 3 days. The inclusion of supplementary cementitious materials such as blast furnace slag at high replacement levels in concrete mixtures is common. The incorporation of slag, typically with higher alumina contents than OPC, can additionally impact the sulfate consumption as they are expected to influence the reaction of the aluminate phase at an early age.
Additionally, slags have variable alumina content ranging between 7% and 18%, which can further influence this tendency. This study investigates the influence of fineness, C3A, C4AF content of cement, and Al2O3 content of slag based on compressive strength and isothermal calorimetry testing at one and three days. A matrix consisting of four cements with variable fineness, C3A, C4AF content of cement, and two slags with low and high alumina contents was investigated for optimum SO3 content. A single replacement level of 50% by mass of slag was used.
The results suggest the strong influence of C3A, C4AF content of cement, and Al2O3 content of slag and mean particle size and fineness of both cement and slag on optimum SO3 content based on the heat of hydration and compressive vi strength testing. An expression incorporating these parameters is suggested for the optimization of SO3 content for use in slag-blended systems. vii Chapter 1: Introduction Supplementary cementitious materials (SCMs), which are natural materials or industrial byproducts, have been intensively used in the construction industry for decades since sustainability, performance, and carbon footprint have been gaining global attention [1]–[4]. SCMs are used as a partial replacement of Portland cement to improve both fresh and hardened concrete properties [5], [6].
One of the commonly used SCMs around the world is ground granulated blast furnace slag (GGBS). Slag manufacture and utilization in the concrete industry have been consistently increasing [7], [8]. Since slag substitutes ordinary Portland cement (OPC), it can provide increased durability, workability, higher ultimate strength, cost efficiency, and reduced CO2 emissions [9]–[14]. However, slag reacts relatively slowly than OPC, and it demonstrates lower early age strength development.
Even though the levels of replacement are restricted, contributions of slag into concrete and construction are expressed in many research reports [10], [13]–[19]. From a historical perspective, the determination of sulfate content in cements and blended cements have become a crucial problem for researchers. Lerch [20] conducted the first most comprehensive research on sulfate optimization of cement paste and mortar. Researcher optimized sulfate content of cement based on compressive strength, heat of hydration (HOH), and also with length change of mortar bars stored in water.
The researcher demonstrated how compressive strength and HOH present virtually identical results on sulfate optimization. 1 Therefore, Lerch [20] has been a pioneer and inspired by many studies on sulfate optimization of cement and cementitious systems. Sandberg and Bishnoi [21] displayed sulfate optimization of calcined based LC3 cement using isothermal calorimetry. Researchers steadily increased sulfate amount in LC3 cement, measured the heat of hydration (HOH) via calorimetry, and selected the maximum HOH at the desired age.
Mei-Zue and et al. [22] focused on the optimization of sulfate in different blended cementitious systems. Researchers' experimental results showed that different content of blended cementitious systems needed different amounts of sulfate content for sulfate optimization. Therefore, different gypsum contents such as calcined gypsum, which have different solubility and activity, were influenced by sulfate optimization.
Another inspirited research from Lerch's work was "on optimization of sulfate level on fly ash-OPC system" studied by Niemuth [23]. Even though there was no specific standard to determine sulfate optimization on blended cement systems, the researcher also used compressive strength test and isothermal calorimetry to determine sulfate demand on fly ash-OPC systems in his dissertation and paper [23], [24]. The researcher demonstrated that fly ash demand increased in optimum sulfate in the OPC-fly ash system. The researcher examined in detail the effect of sulfate optimization on the OPC-fly ash system, which not only depends on the physical properties of fly ash, like particle size but also depends on the chemical properties of fly ash.
Mohammed and Safiullah [25] studied and optimized sulfate content of Algerian Portland cement. The authors' conclusions demonstrated that qualities of cement paste and mortar such as setting time, strength, drying shrinkage, degree of hydration, and so on, were unfavorably affected when calcium sulfate dihydrate was added below or above the optimum of sulfate content in cement. 2 As detected by Lerch [20] and other researchers [22]–[25], there are many certain factors affecting sulfate demand on cement and cementitious systems. Tricalcium aluminate (C3A), fineness, and alkalis are the most well-known factors affecting the sulfate demand for cement.
On the other hand, the incorporation of slag, typically with higher alumina contents than ordinary Portland cement (OPC), can additionally impact the sulfate consumption as they are expected to influence the reaction of the aluminate phase at early ages. Besides, higher alumina slag content can induce more rapid slag hydration in a cement-slag system [26]. Furthermore, Kocaba's research [10] proved that slags favored the hydration of the ferrite (C4AF) phase in cements. Therefore, C4AF in cement and alumina content in slag also have been taken into consideration on sulfate optimization of slag-cement systems in this research.
Isothermal calorimetry, which is equipped with unique temperature control systems usually has high repeatability compared to compressive strength tests. The test results can be obtained without stopping the experiments at any time, in other words, it provides continuous information [20], [23], [27]. Nevertheless, making specimens for compressive strength tests needs intensively physical labor, and specimens have to be kept in ambient, temperature-controlled lab room or cabinet [28]. On the other hand, from past to present compressive strength test has been commonly used in the concrete industry.
Therefore, both compressive strength tests and isothermal calorimetry were used to determine sulfate optimization in cement-slag systems at one day and three days in this research. The objective of this investigation is to illustrate that the substitution of cement with slag will alter the ideal sulfate level by expanding the sulfate demand.