| In recent years,with the rapid development of the economy,the demand for wall materials in the construction industry is increasing,and the standards for wall materials in the country are also constantly improving.At present,with the support of national policies,China is vigorously researching and developing energy-saving,environmentally friendly multi-functional green new wall materials,and encouraging enterprises to use renewable resources such as industrial waste residue and agricultural waste to produce new wall materials.Phosphogypsum is a renewable industrial waste that can be used to prepare building wall materials after treatment and realize the comprehensive development and utilization of phosphogypsum.It can not only protect the environment,save resources,but also provide a basis for the innovation of new wall materials in China.This topic uses phosphogypsum after special process pretreatment as the basic raw material,adding cement,mineral powder and other composite cementitious materials,foaming gypsum material is prepared by foaming.And It is supplemented with various admixtures to optimize its performance,and a systematic analysis of the internal microstructure of the material is also carried out..Through a large number of experimental studies,the optimal mix ratio of foamed gypsum materials and the optimum blending amount of various admixtures were obtained,and the foamed gypsum wall materials with better comprehensive performance were obtained.The main research results are as follows:(1)The effects of retarder,cement,mineral powder and foaming agent on the properties of phosphogypsum composite cementitious materials were analyzed through experiments,the comprehensive analysis showed that the optimum blending range of cement was 5%to 15%,the optimum dosage of mineral powder is 4%to10%,the optimum dosage of foaming agent is 0.6%to 1.2%,and the optimum dosage of retarder is 0.05%.(2)The orthogonal test mixture ratio design of foamed gypsum material was carried out to analyze the influence primary and secondary order of water-to-material ratio,foaming agent dosage,mineral powder content and cement content on the properties of the material,the comprehensive analysis of compressive strength and dry density two key indicators to obtain the optimal mix ratio of foamed gypsum material,water-to-material ratio is 0.50,the foaming agent content is 0.9%,the mineral powder content is 6%,and the cement content is 10%..At this time,the compressive strength is 5.34MPa and the dry density is 726 kg/m~3.(3)Adding proper amount of water reducing agent and quicklime can effectively improve the physical and mechanical properties of foamed gypsum materials,the optimum dosage of water reducing agent is 0.2%,and the optimum dosage of quicklime is 1.5%..(4)The effects of polypropylene fiber and basalt fiber on the mechanical properties of foamed gypsum materials were studied.The results show that the proper amount of polypropylene fiber can improve the mechanical properties of the material more effectively.When the polypropylene fiber content is 0.8%,the compressive strength of the material increased by 4.1%,the flexural strength increased by 45.4%,the dry density was 733kg/m~3,and the softening coefficient was 0.63,the overall performance was good.(5)The effects of dispersible polymer powder and stearic acid emulsion on the strength and water resistance of foamed gypsum materials were studied.The results showed that the proper amount of stearic acid emulsion can improve the water resistance of the material more effectively under the premise of ensuring the strength.When the stearic acid emulsion content is 3%,the compressive strength of the material is 5.24MPa,the water absorption rate is decreased by 51.3%,and the softening coefficient is increased by 17.5%.(6)The feasibility of applying foamed gypsum material in wall materials was analyzed,and some suggestions were given in terms of production process,performance standards,engineering construction and design. |
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