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Experimental study and application of new foam concrete in closed wall of coal mine

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Document pages: 13 pages

Abstract: Due to the air tightness of the coal wall, the residual air leakage caused by spontaneous combustion of the coal wall is prevented. A new type of foam concrete (FC) has been developed to control air leakage. A series of physical and mechanical tests were carried out on FC samples of four densities (250, 450, 650 and 850   kg m3). Use thickener to control FC shrinkage and collapse. With the increase of density, the permeability of FC decreases exponentially. On the contrary, under uniaxial compression, the compressive strength( σ) And elastic modulus (E) increase exponentially and linearly with the increase of density respectively. Under the condition of triaxial compression, the compressive strength of FC increases with the increase of confining pressure and shows slight plasticity.The impact experiment showed that the dynamic compressive strength of the FC appeared to be strain-rate dependent, and it increased with an increase in the strain rate and pressure under a confining pressure. Without a confining pressure, the variation in compressive strength exhibited a slow decrease. Applied FC resulted in a 5 MPa 28-day compressive strength of the airtight wall with no remaining fissures and with air leakage suppression to the gob.

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