Preparation and properties of foamed lightweight soil with large content of limestone powder
The foamed lightweight soil prepared by replacing part of the cement with limestone powder can be used as the filling material of the subgrade to reduce the sedimentation and additional stress of the foundation.The results showed that in the ordinary foamed lightweight soil system,with the increase of limestone powder mixing,the flow value and strength of the foamed lightweight soil were gradually reduced,and the preparation design strength of 1.0 MPa foamed lightweight soil should not exceed 20%;In the high-performance foamed lightweight soil system,the water-solid ratio was 0.4,the amount of water reducer is 0.2%,and the water reducer and foam agent had good compatibility,and the amount of limestone powder could reach 40%.The incorporation of limestone powder in foamed lightweight soil is conducive to the dispersion of foam,and it was not easy to form large pores,more than 0.5 mm large pores are few,most of the pore size is below 0.2 mm,and the pore size was uneven.The pore shape was spherical,and the connecting hole was less,mostly a separate hole.Among the hydration products of the limestone powder foamed lightweight soil samples,the characteristic peaks of C-S-H,CH,AFt and single carbide calcium aluminate C3A·CaCO3·11H2O are obvious.Limestone powder has the effect of accelerating cement hydration in the early days.
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