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The adobe material as an important building materials, a glorious page in the history of the development of human society, its superior thermal insulation, low energy consumption and no pollution is still the target of many construction materials development. However, with the development of society, the adobe material is now facing new challenges. On the one hand, as the main raw material quality clay adobe material resources is limited mining use, at the same time high-quality land salinization phenomenon is becoming increasingly serious, large areas of saline soil resources need to take advantage of; On the other hand, traditional adobe the drawbacks of building materials, such as low-intensity, large deformation, water intolerance performance, unable to meet the requirements of social development, and gradually withdraw from the stage of history. To this end, it is necessary to explore new ways of development of adobe materials, the development of environment-friendly new materials, and continuously improve the performance of the material to expand the scope of application of the adobe material. In this paper, based on analysis of coastal saline soil physical and chemical properties, the use of alkaline solution to the activation analysis of the potential activity of silica-alumina, and saline soil - fly ash composite system is supplemented with fly ash through the process impact factors optimization of its parameters to determine the preparation of a new type of cementitious material. The experiments showed that the saline soil - fly ash composite binder good physical and mechanical properties and durability. Finally, the X-ray diffraction, infrared spectroscopy, scanning electron microscope and other equipment, conducted in-depth analysis and research on saline soil - fly ash composite cementitious reaction process and its product, initially expounded alkali excitation conditions Composite cementitious reaction mechanism, the results are as follows: (1) from the situation of saline soil in the dissolution of the active SiO2 and Al2O3 and soil changes, sodium hydroxide excitation ideal process conditions for saline soil activity : concentration of sodium hydroxide to 10 mol / L, the activation temperature of 60 ° C, 24 h treatment. The the Alkali Activated soil mass of Si-O, Al-O, and so on the characteristic peaks telescopic wpe3E.gif occurred, the mineral structure group a certain degree of destruction or disintegration, dissolution of the active silica-alumina material can be further involved in the reunion reaction. (2) alkaline activator alone to excite the sample in saline soil strength is not high, the durability is not ideal. Fly ash together constitute the saline soil - fly ash composite system, which blends 40% fly ash can significantly improve the activating effect, fly ash content from 20% to 40%, the compressive strength of the specimen the strength growth nearly doubled, the softening coefficient increased from 0.61 to 0.79, keeping 60% of the amount of fly ash can be very good suppression of the damage to the surface of the material, to reduce the loss of mass of the specimen. From the trend of changes in the intensity of the composite binder, the concentration of sodium hydroxide in the alkaline activator solution should be less than or equal to 10 mol / L sodium hydroxide and sodium silicate mixture ratio of 1.0 is appropriate. (3) sodium chloride saline soil - the overall strength of the fly ash composite binder acts as a break, but the appropriate dosage of sodium chloride, is conducive to the material early strength continued to improve, such as sodium chloride content is 1% and 3%, 3d to 28d compressive strength value, respectively, an increase of 19.1% and 20.5%, respectively. (4) The analysis results of XRD and FT-IR activated alkaline solution the active aluminosilicate depolymerization reconstruction system, the formation of zeolite-like structure of the product and the aluminum silicate network in the final cementitious product, This is a key material to obtain superior performance. (5) SEM and EDS studies have shown that changes in saline soil - fly ash composite binder system product morphology and migration of elements there are differences as the fly ash content in the system changes, the reaction gelling substance, the density of the structure are influential.
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