Experimental Study And Mechanism Analysis Of Spontaneous Combustion Coal Gangue Application In Cement, Concrete And Subgrade

China is a developing country with coal as the main energy, in the primary energy consumption, coal accounts for more than70%, and for a long period of time in the future, the energy structure will not change. With the enjoyment of coal for industrial innovation energy,at the same time, it also suffers from spontaneous combustion of coal gangue, coal gangue dumps and collapse, air pollution, water pollution, the occupation of cultivated land and leads to loss of life and property and other problems.The spirit of "turn material resources to good account, obtain raw material locally" principle, the spontaneous combustion of coal gangue in cement, concrete and subgrade materials used as the main line. Based on the physicochemical properties of coal gangue comprehensive utilization principle, spontaneous combustion of coal gangue activation mechanism, spontaneous combustion of coal gangue cement admixture, spontaneous combustion of coal gangue geological polymer material, spontaneous combustion of Coal Gangue light aggregate concrete, spontaneous combustion of coal gangue soil material aspects of coal gangue comprehensive utilization of building materials in the field of the theory and application of technical problems, to all-round, three-dimensional application of coal gangue. This thesis studies the following aspects:(1) Through the test of basic properties of spontaneous combustion of coal gangue,I get the physical and chemical characteristics of Liaoning Province, Fuxin mining area of spontaneous combustion gangue mineral composition and mechanical properties, then I can determine the possible utilization of spontaneous combustion of coal gangue cement and concrete.(2) The compound method which combines mechanical activation and chemical activation is adopted to carrying out on the spontaneous combustion gangue activity. Based on the orthogonal test design method, I study the using of Fuxin coal mine spontaneous combustion coal gangue preparation feasibility of spontaneous combustion of coal gangue cement and the best mixture ratio and the concrete preparation method.(3) Using coal gangue as the main raw material to produce Green cementitious materials, geological polymer,in21th Century and provide a new application field for the comprehensive utilization of coal gangue. Researching ligand alkali excitation agent on the properties of geopolymer excitation function, through experiments and mathematical analysis optimization of the mix proportioning of the spontaneous combustion coal gangue, slag, fly ash geopolymer, verify the reliability of the indices such as its strength.(4) Using artificial grading of spontaneous combustion gangue sand and coal gangue, with the coal gangue spontaneous combustion Portland cement as the cementing material. Based on lightweight aggregate concrete mix design method, respectively with different strength grade of coal gangue coarse and fine aggregate concrete. And compare Strength and Working performance with common cement of Coal gangue concrete, discussion on the characteristics and mechanical properties of coal gangue concrete, study feasibility of a large amount of coal gangue and its application in concrete.(5) Through lime fly ash cement modified spontaneous combustion coal gangue mixture as roadbed material, make it become effective way to scale consumption of coal gangue. First, by using the lime-fly ash to improve the spontaneous combustion of coal gangue mixture ratio design, full of water and no side limit compression strength, compaction characteristics. Analysis of two ash stabilized combustion coal gangue mixture probability as roadbed materials, and the mechanism of strength. Results show that coal gangue mixture of two ash stability cannot meet the requirements of northern antifreeze. Through the comparative test of different cement content, I give the "three ash" stable spontaneous combustion coal gangue mixture durability of optimum mix, provide reference for engineering application, and analyse its mechanism.(6) As the test data for a sample, according to the result of the test data, the use of finite element analysis and calculation method, the FLAC3D platform, simulation studies under the action of different cars, the gangue subgrade settlement deformation, plastic zone distribution, stress distribution and other characteristics, to the reliability of the comprehensive analysis of coal gangue subgrade.Draw the following main conclusions(1) Spontaneous combustion of coal gangue is rich in silica and alumina and the content of great, the spontaneous combustion of coal gangue and building materials dual approximation in the "quality" and "quantity". So as to determine the spontaneous combustion of coal gangue in cement, concrete and soil materials in the scale of use is the most effective approach.(2) Application of spontaneous combustion of coal gangue in concrete and subgrade materials is feasible:due to the presence of grading defects, need crushing screening can meet the requirements of coal gangue particle gradation; compared with the crushed stone soil, the water stability is poor; through the study of the spontaneous combustion of coal gangue CBR value test result shows red gangue and ash gangue can to meet the strength requirements of road material.(3) Test and analysis shows that:gangue activity is much higher than ordinary artificial sand, the effect of fineness on the strength of test block maximum. Fuxin mine spontaneous combustion gangue can be used as the active preparation of hybrid materials gangue portland cement through the mechanical and chemical activation, when the spontaneous combustion gangue:slag:gypsum:ordinary portland cement=25:10:3:62ordinary portland cement, spontaneous combustion of coal gangue cement strength reached the maximum.(4) Spontaneous combustion of coal gangue and slag-Fly Ash Geopolymer best ligand: types of sodium silicate and potassium hydroxide, ratio of1:1. By quadratic response surface test regression analysis showed that there is a clear quantitative relationship between Sodium silicate modulus and strength inspire agent dosage and mortar. The optimal sodium silicate modulus was1; activator dosage was22.6%(the optimal total cementitious material).(5) The spontaneous combustion of coal gangue thickness of Portland cement, particle size distribution and good spontaneous combustion of coal gangue aggregate preparation of spontaneous combustion gangue concrete, proved the feasibility of large amount of spontaneous combustion of coal gangue concrete; Through the contrast test to get aggregate ratio exists "fit effect", the strength of concrete is significantly improved.(6) The gangue roadbed mixture unconfined water compressive strength to meet the regulatory requirements, but lower strength instability; When the cement content of3%, the best of flyash cement modified gangue mixture specimen.(7) Based on FLAC3D numerical simulation, the variation analysis of subsidence deformation, stress distribution, the distribution of plastic zone, proved in the the flyash cement modified gangue roadbed material is feasible.