Mixproportion And Mechanism Analysis Of Chemically Bonded Phosphate Ceramic Material

Chemically bonded ceramic material with a satisfactory mechanical performance and thermostable performance which beiongs to the inorganic cementitious material,this kind of material usually be used to repair the airport runaway and traffic roadways quickly. The prepare of chemically bonded ceramic material takes fly ash, coal gangue and slag as the main raw materials. The chemically bonded ceramic material is an environmentally friendly material because during the preparation there is almost no gas like SO2?NO2 and CO2 exhausted. Chemically bonded ceramic material can be divided into alkali-activated chemically bonded ceramic material and acid-activated chemically bonded ceramic material. The study about alkali-activated chemically bonded ceramic material is relatively mature while the research time of acid- activated chemically bonded ceramic material is short, the polymerization mechanism of acid- activated chemically bonded ceramic material is still unclear, the early strength is still unsatisfactory, the study on the thermostable performance and fiber composite are still rare.For improving the workability of acid- activated chemically bonded ceramic material this issue choose aluminum phosphate solution as the acid stimulate solution, choose metakaolin as the matrix material and mix with balanced amout of magnesia to prepare chemically bonded phosphate ceramic material. A series of research about the major property and application of chemically bonded phosphate ceramic material were carried out with variety kinds of macro test method and micro detection mean. The main contents are shown as follows:(1) The study of optimal mix proportion of chemically bonded phosphate ceramic material.Select the P/Al molar ratio of phosphate solution, the quality ratio of phosphate solution and metakaolin and the mass fraction of magnesia as the controls parameters, take the mechanical properties and setting time of the chemically bonded phosphate ceramic material as the measurable indicators, the chemically bonded phosphate ceramic material with excellent performance was finally been carried out though orthogonal test, verification test and optimizing test. The specific optimal mix proportion is the P/Al molar ratio of phosphate solution is 3, the molar ratio of Si atom and P atom is 1.2 which represent the the quality ratio of phosphate solution and metakaolin, the mass fraction of magnesia is 18%.(2) The study of polymerization mechanism of chemically bonded phosphate ceramic material.The chemically bonded phosphate ceramic material with the optimal mix proportion was seceleted as the detection material. A variety kinds of micro detection mean such as XRD, FTIR, SEM, DSC-TG, MIP and XCT were put into force to observe the microstructure of the micro detection mean, so as the discussion of the polymerization mechanism. The results indicates that the polymerization mechanism of chemically bonded phosphate ceramic material was reacted between the P-O layer of phosphate solution and the Al-O layer of metakaolin, the molecular chain which made up by silicon-oxygen tetrahedron and aluminium-oxygen was connected to be a three-dimensional network structure by the phosphorus-oxygen tetrahedron. In addition, the whole structure was neutral by the charge-balanced of PO43-and Al3+. The addition of magnesia shortened the setting time and improved the early strength of material, for another, the magnesia reacts with the unreacted phosphate and generated a crystal MgHPO4?3H2O, rather than take part in the polymerization reaction. The crystal MgHPO4?3H2O decreased the size of the inner pore and improved the microstructure of the material.(3) The study of the thermostable performance of chemically bonded phosphate ceramic material.The samples were prepared with the optimal mix proportion and then high-temperature calcined while the temperature are 250?,500?,750?,1000? and 1250? respectively. After the sample cooled down compression test and XRD, SEM test were put into effect. The results indicates that the chemically bonded phosphate ceramic material sintered when the temperature was up to 1000?, after sintering reaction, the chemically bonded phosphate ceramic material turns to be a continuous dense material and mechanical property improves gradually.(4) The mechanical property of phosphate based fiber composite material. The phosphate based fiber composite material was carried out by the mixing of balanced amount of chemically bonded phosphate ceramic material and fiber. The results of bending test showns that the bending strength and elastic modulus of the phosphate based fiber composite material improved evidently, that is to say, the addition of fiber can improve the ductility of the material. The results of the mechanical danamic elastic test showns that the phosphate based fiber composite material is an inorganic polymer viscoelastic material. Under alternate load, the material mainly characterized by elastic deformation.