Thesis Abstract

Abstract
Granulated Calcined Clay (GCC) is a byproduct of the calcination process used in the production of clinker for cement. This research project aims to explore the potential of utilizing GCC to enhance the strength properties of concrete. The study involves investigating the effect of incorporating different proportions of GCC as a partial replacement for cement in concrete mixes. Various tests including compressive strength, flexural strength, and durability assessments will be conducted to evaluate the performance of the GCC-enhanced concrete. The research methodology includes preparing concrete mixtures with varying percentages of GCC, typically ranging from 10% to 30% by weight of cement. The fresh and hardened properties of these mixtures will be examined to determine the optimal GCC content for achieving high concrete strength. Special attention will be given to the hydration characteristics and pozzolanic reactions of GCC in the concrete matrix. Microstructural analysis using techniques such as SEM and XRD will be employed to understand the mechanisms responsible for the strength development in GCC-incorporated concrete. Furthermore, the durability aspects of GCC concrete will be assessed through tests such as water absorption, chloride ion permeability, and resistance to sulfate attack. The study will also investigate the long-term performance of GCC concrete in terms of shrinkage and creep behavior. The results obtained from these tests will provide insights into the potential applications of GCC as a sustainable supplementary material in concrete construction. The outcomes of this research are expected to contribute to the development of high-strength concrete mixes using GCC, thereby reducing the reliance on traditional cement materials and promoting sustainability in the construction industry. By utilizing a byproduct like GCC, this study aims to address environmental concerns associated with cement production while enhancing the mechanical and durability properties of concrete. The findings will be valuable for engineers, researchers, and industry professionals looking to optimize concrete mix designs for improved performance and reduced environmental impact. In conclusion, the research on making high-strength concrete from granulated calcined clay presents a promising opportunity to innovate concrete technology towards more sustainable practices. The comprehensive investigation into the mechanical, durability, and microstructural properties of GCC concrete will offer valuable insights for its practical implementation in construction projects.

Thesis Overview

INTRODUCTION

1.1   BACKGROUND OF THE STUDY

  Cement is a significant source of anthropogenic release of carbon dioxide. The CO2 derives mainly from kiln fuel combustion, transport and distribution and decarbonating of limestone. The latter source is fairly constant. Thus one procedure to lower the release of carbon dioxide is reducing the clinker content of the cement by shifting the production from CEM I to CEM II or CEM III cements. Another approach is replacing cement partially in concrete mix design by Type II additions like fly ash, granulated blast furnace slag or silica fume. An alternative to these afore mentioned options provides the use of calcined clay either as reactive part of the cement [1] or as Type II addition in concrete [2]. Metakaolin is known as a very reactive calcined clay and has been in focus of many investigations [e.g. 3, 4, 5, 6, 11]. Its widespread use in concrete is prohibited mostly by its high price compared to other Type II additions. Suitable and less expensive clay qualities consist rather of a mixture of clay minerals, which range between the clays used in the ceramic industry and those required for the cement production than of single type clay minerals. Thus it is worth taking a closer look at mixed clays. The reactivity of any calcined clay depends on both its mineral composition and the calcination temperature [e.g. 1, 3 – 11]. In most cases these investigations used homogenous clay samples that were calcined at constant temperature and for a period of several hours. Furthermore these clays were ground prior to calcination ensuring a complete reaction to take place. If coarse crushed clay is fed into a rotary kiln it is exposed to varying temperatures on its journey through the kiln combined with temperature gradients due to the size of the chunks after crushing and in addition a varying degree of oxidation. This paper focuses on the impact of such calcined clay on various mortar and concrete properties and its inherent ecological potential.