Study On The High Water Cementing Material With High Dosage Fly Ash For Regenerated Roof

China is rich in coal resources, the characterized of distribution is thick seam storage, yield both very rich, accounting f or the total raw coal 45%; and the other characterized is the coal amount of located under villages ? railroads and surface buildings is great, and with China's sustained economic development,the coal resources exploitation and consumption continued large, result the coal amount of the "three under" is a growing proportion of the total now. For thick coal seam and the "three under" underground coal seam mining, In order to prevent the earth's surface collapsed, buildings and farmland are destroyed, landslides and gob fire at the mining process, slicing and coal goaf grouting filling is the feasible ways. This thesis mainly from the sulphur aluminate cement preparation, gypsum and lime components design,the water solid ratio and the mixed admixture of the high water cementing material, to improve the performance of the high water cementing material. Analysis of the influence of various factors on the performance of high water cementing material, to ensure the safety and stability of working face, improve coal recovery rate.The pater based on the determination of various performance like setting time,drainage rate and seed setting rate, material viscosity, strength and internal reaction temperature etc of high water cementing material, to optimize material proportioning.Using XRD and SEM modern technology to analyzes the high water cementing material microscopic characterization.Through the above research results are as follows:(1)The mineral components of sulfur aluminate cement affect the performance of high water cementing material. The ratio of C4A3-S /?-C2 S is bigger, the more conducive to improve the performance of the high water cementing material. With increasing content of cement C2, increased ?-C2 S, C4A3-S decrease is bad for the performance of high water cementing material,Its setting time is extended, C2 cement mixed with 20% compared with the undoped, the setting time extended by 38%,the drainage rate increases, seed setting rate decreases.The strength of the material to reduce a lot, C2 content of 5% and 20% of the 1 d compressive strength than 0%content was reduced by 26.3% and 26.3% respectively, the C2 content of 5% and 20%vs 0%,the compressive strength of 1d was reduced by 26.3% and 38.5%, But it is not obvious to reduce material reaction temperature.(2)Gypsum dissolution characteristics have influence on the performance of high water cementitious materials. Through experiment contrast, anhydrous anhydrite is more suitable for the raw materials of the high water cementing material preparation of this paper research.(3)The impact of different gypsum and lime proportion for high water cementing material setting time?drainage rate and seed setting rate is not great. gypsum lime proportion change from 65/35 to 95/5, the setting time of high water material are within 15-20 min,the drainage rate is no more than 2%,the Seed setting rate are all over 95%, Impact the material strength showed a trend of first increases then decreases. According to the comparison of the overall performance, in gypsum lime proportion is 80/20, the various performance to the optimal.(4) In the condition of same water solid ratio, the setting time of high water cementing material was longer when larger dosage of fly ash, When the dosage of fly ash under the same conditions, Its setting time become larger when Water-solid ratio increases, In the condition of different water solid ratio, the effect of fly ash dosage on high water cementing material drainage rate and seed setting rate is not obvious, but the effect of fly ash dosage and water solid ratio is so great,for the strength and internal heat of High water cementing material. when the water solid ratio is1:1, the dosage of fly ash is 60%, which 1d compressive strength of 2.1MPa,7d is 2.8MPa. And the internal reaction temperature decreased from the control group of 42.9 ? to 34.9 ?.(5)In the condition of different water solid ratio,change the dosage of fly ash can effectively reduce the economic costs of high water cementing material. in the water solid ratio is1:1, the dosage of fly ash is 60%, in comparison with the control group of the water solid ratio is2:1, the dosage of fly ash is 0%, Its strength is quite, but the cost reduced as much as 54.6%.