Since the energy crisis in 1970’s, research on low energy cements with low CO2-emissions has been increasing. Numerous solutions have been investigated, and the goal of this original research is to create a viable hybrid cement with the components of both Ordinary Portland cement (OPC) and calcium sulfoaluminate cement (CSAC), by forming a material that contains both alite and calcium sulfoaluminate clinker phases. Furthermore, this research focuses on keeping the cost of this material reasonable by reducing aluminum requirements through its substitution with iron. The aim of this work would produce a cement that can use large amounts of red mud, which is a plentiful waste material, in place of bauxite known as an expensive raw material. Modified Bogue equations were established and tested to formulate this novel cement with different amounts of ferrite, from 5% to 45% by weight. This was followed by the production of cement from reagent chemicals, and from industrial by-products as feedstocks (fly ash, red mud and slag). Hydration processes, as well as the mechanical properties, of these clinker compositions were studied, along with the addition of gypsum and the impact of a ferric iron complexing additive triisopropanolamine (TIPA). To summarize this research, the influence of the addition of 5-45% by weight of ferrite phase, was examined with the goal of introducing as much red mud as possible in the process without negatively attenuate the cement properties. Based on this PhD dissertation, the production of high-iron alite-calcium sulfoaluminate-ferrite cements was proven possible from the two sources of raw materials. The hydration processes and the mechanical properties seemed negatively affected by the addition of ferrite, as this phase was not hydrated entirely, even after 6 months of curing. The usage of TIPA counteracted this decline in strength by improving the ferrite hydration and increasing the optimum amount of gypsum required in each composition. The mechanical data were equivalent to OPC strengths for some compositions with 25% ferrite. This preliminary work constitutes the first research phase of this novel cement and requires additional research for its improvement. Topics for additional research are identified in this dissertation.

The ever-increasing quantity of by-products generated from burning coal in the production of electricity has brought about the need for new areas of utilization. This study examined the use of FGD gypsum and fluidized bed combustion ash along with Class F fly ash in the production of low-energy, 100% by-product cement blends. The cement blends used the advantageous properties of the by-product materials to create cementing properties rather than energy intensive clinker used in ordinary portland cement. The FGD gypsum was converted to hemihydrate which rapidly hydrated to provide the cement with early strength gains, whilst the fluidized bed combustion ash reacted with the Class F fly ash to form pozzolanic cementitious phases which provided the longer-term compressive strength and possibly resistance to weathering. The rate of compressive strength gains and minimizing detrimental expansion were two properties of particular interest in the study. Chemical admixtures were used to improve the compressive strengths of the cement mortars and decrease their solubility.

This study is dedicated to give a production route for a kind of low energy cement called alinite cement using the waste material of soda industry as the main raw material. Soda solid waste, clay and minor amount of iron ore were mixed with certain quantities and burned at six different burning temperatures of 1050, 1100, 1150, 1200, 1350, and 1450 &ordm / C. The resultant clinkers were investigated by mineralogical and chemical analysis. Mineralogical analyses were performed by X-Ray Diffraction (XRD) technique. XRD analyses revealed the formation of alinite phase in the clinkers. Chemical analyses were performed by X-Ray Fluorescence spectroscopy technique and by wet chemical analysis. Especially, free lime content of the clinkers was searched and an optimum burning temperature was determined. In order to find the compressive strength of the alinite cement, larger amounts of alinite clinker were manufactured in wet rod shape raw mix in a laboratory type of furnace at 1200, 1350 and 1450 &ordm / C. The results have shown that forming alinite phase requires ~6wt % chlorine. Alinite clinker is obtained using soda waste at the temperature range between 1050 and 1200 &ordm / C. However, the free CaO becomes much lower as 0.12 at 1200 &ordm / C. Moreover, a lime saturation factor of 76, which is lower than ordinary Portland clinker is obtained. Satisfactory compressive strength was achieved by gypsum addition.