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Sulfate Attack on Concrete - Chapter 2

Chemistry and physics of cement paste - Bê tông là một vật liệu composite vô cơ được hình thành, dưới hình thức đơn giản của nó, từ một chất kết dính phản ứng đơn giản, phụ một trơ, và nước. Trong thực tế, bê tông hiện đại là một vật liệu phức tạp thường được làm bằng một hình thức của xi măng thủy lực, tổng hợp tốt và tất nhiên, khoáng sản và hóa chất phụ gia, và nước trộn. Các thuộc tính cấu trúc bê tông thường phụ thuộc chủ yếu vào các phản ứng hóa học. | 2 Chemistry and physics of cement paste 2.1 CONCRETE COMPONENTS Concrete is an inorganic composite material formed in its simplest form from a simple reactive binder an inert filler and water. In reality modern concrete is a complex material typically made of a form of hydraulic cement fine and course aggregate mineral and chemical admixtures and mix water. The structural properties of plain concrete depend primarily on the chemical reactions between the cement water and other mix constituents as well as on the spatial distribution and homogeneity of the concrete components. The chemistry structure and mechanical performance of the products of the hydration reactions in concrete are in turn influenced by the production processes and the environmental conditions prevailing during the production of concrete. Thus in designing concrete for service in a specific environment not only the concrete materials per se but also the processing techniques and environments of use have to be taken into account. This fact is sometimes neglected in engineering practice. 2.1.1 Hydraulic cements Modern hydraulic cements cements capable of developing and maintaining their properties in moist environment are based either on calcium aluminates calcium aluminate or high-alumina cements or on calcium silicates Portland-clinker based cements . In this work focus will be entirely on Portland cements and their modifications. Portland cements and other Portland clinker-based hydraulic cements are produced by inter-grinding Portland cement clinker with limited amount of calcium sulfate gypsum hemihydrate anhydrite industrial by-products and often with one or several mineral components such as granulated blast furnace slag natural or artificial pozzolan and or limestone. Cement clinker is a precursor produced by heat treatment of a raw meal typically containing sources of lime silica alumina and ferrite. The main reactive components of 2002 Jan Skalny Jacques Marchand and Ivan Odler Table 2.1 .