Study On Foamed Cement Solidified Filling Fire Preventing And Extinguishing Material

The coal spontaneous combustion disaster is serious in China,and the burning factors are variable.It is relevant statistics showed that with the comprehensive application of fully mechanized caving mining,especially the coal-free mining technology,the spontaneous combustion of roadway caused by air leakage accounts for more than 60%of the total spontaneous combustion of coal in coal mine.At present,the fire extinguishing material filling technology is a widely applied and effective fire prevented technology.But the key to determining whether the filling effect has achieved the desired goal is the filling material selection.The article based on the investigation of domestic and foreign fire extinguishing filling materials,combined coal spontaneous combustion mechanism,and successfully developed a foamed cement solidified filling material which is made of ordinary portland cement,sulphoaluminate cement,foaming agent,gypsum and polypropylene fiber.Tested the performance parameters such as initial setting time,fluidity,expansion ratio and compressive strength of the filling material.By single factor analysis to study the effect of various dosages on the properties of solidified filling materials.According to the orthogonal test comprehensive range analysis,and use four performance indicators as the standard.The final optimum ratio is A3-B3-C2-D3-E2,the water-cement ratio is 0.5,the ordinary portland cement is 40%,the sulphoaluminate cement is 60%,the foaming agent is 1%,the gypsum is 6%,the polypropylene fiber is 0.4%.The performance of the solidified filling material is optimized under this ratio,and the initial setting time is about 120min,the fluidity is about 130mm,the expansion ratio is 2-3 times,and the compressive strength is 2?8MPa.Using SEM to study the microscopic characteristics of foamed cement solidified filling materials under different proportion and curing ages.As the water-cement ratio increases,the internal pores of the solidified filling material increase;The incorporation of the blowing agent does not affect the hydration product of the solidified filling material,however,the pores between the hydration products become larger and the structure become looser,resulting in a decrease in the compressive strength of the solidified filling material.Finally,making the 21303 wind tunnel of Cuimu Mine as the background of industrial experiment.According to the actual characteristics of mine fires and technical requirements for filling,designing a "preparation-transport-fill-effect verification" filling solution.Through the estimating the filling area,the design of the filling equipment and determination of the construction parameters,an effective filling technical solution has been developed.Successfully managed the spontaneous combustion disaster of 21303 wind lane coal,laying a foundation for the application of foamed cement solidified filling materials.