| A large number of stone powder was produced inevitably during the production in stone factory, the treatment method tend to be less and costly, and improper handling can easily cause serious environment pollution. Currently, only a small number of stone powder are recycled, most are stacked or turned to be powder foundation. According engineering application situation of stabilized soil with different dosage cement, the paper puts forward two methods to deal with stone powder. One method is to be stabilized soil with a small amount of cement and lime to subgrade subbase, the another is to apply stabilized soil with a small amount of cement as a foundation. To achieve the purpose of turning waste into wealth and reducing engineering cost, the article concrete study the physical and mechanical properties of pure powder, solidified powder with low dosage of cement and solidified powder with high dosage of cement. Results showed that:(1)Stone powder is a kind of silt which is poor grading, index of low liquid limit, high compressibility and acid. According to the standard ASTM in America it’s classified as SiltL. In form, powder particles is mainly angular and subangular, also have long strips, column and so on. The main mineral composition is quartz(SiO2), potash feldspar(KAlSi3O8) and a small amount of biotite.(2)Stone powder of low permeability, almost impermeable. The permeability coefficient reduce an order of magnitude after adding cement and lime into powder, but it enhance the water stability,and Capillary water absorption coefficient were different degrees of improvement. Powder is low compressibility soil after adding low dosage of cement and lime stabilized.(3) Consolidated undrained triaxial test(CU) indicates that the stability limestone soil with the cement and lime mixture mixed tend to brittle failure. High content does not change significantly the peak stress under different confining pressure. The peak strain gradually reduce with the increase of confining pressure, and along with the age growth peak reducing is more obvious. Different confining pressure on the peak stress effect is not obvious when the cement is higher.(4)Low dosage of cement stabilized stone powder’s unconfined compression strength increasing with the additive agent increased, Strength has increased significantly in the first 28 days, after then growth is very small. According to the specification for design of highway pavement base, low dosage of stabilized soil after 7 days curing of unconfined compressive strength were greater than 0.6 MPa, it could be used for secondary and secondary road base course and subbase and subbase of highways and roads.(5)Studied the curing mechanism of powder, the powder stabilized soil generated hydrated calcium silicate, hydrated calcium aluminate, and hydrated calcium aluminate by cement hydration. Those iron products make the space between the powder particles got better fill. Cement and lime reacts with stone powder to produce the gel-crystallization mixture of mesh, the mixture lower porosity and refine the aperture of the soil stabilization system. Other solid particles in the gelling material that does not participate in the reaction play a role which micro aggregate filling and framework supporting between gelling material. And powder particles itself strength and hardness, all of these greatly improve the strength and durability of lime stabilized soil. |
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