Study On Modification Of Raw Soil Material

The raw soil material is an ancient building material, which is still applied as wall materials in the vast rural areas of our country, and there are also many newly-built in the areas of under-developed econonics and transportation; Because of its outstanding original ecology style, the raw soil arhitectecture for vacation and tourism has become popular; In addition, raw soil materials with high performance are demanded in engineering fields, such as the foundation treatment, eliminate backfill and slope reinforcement. However, the traditional raw soil material has fatal flaws, such as poor compressive strength and low water resistance and volume stability, which restricted its application seriously. Therefore, strengthening its modified research to improve its performance have vital practical significance in expanding the application scope, improving service efficiency and reducing the cost etc..The research is conducted to utilize desulphurization gypsum, fly ash and white lime modified raw soil material. The orthogonal experiment with strength for the main target dose preliminary exploration for the best mixing of modified soil; which mould through compressing and casting. The test result is as follows respectively: Optimum ratio by casting: desulphurization gypsum 20%, fly ash 30%, white lime 8%; Optimum ratio by compression: desulphurization gypsum 10%, fly ash 30%, white lime 4%. The strength of modified materials can be improved by 2 to 4 times. The strength of mode with less doped modified material through compressing is obviously better than the one through casting.The research has further discussed that the influence of modified materials on the performance of raw soil materials. By Adding desulfurization gypsum, fly ash and white lime, the setting time can be reduced and strength can be improved significantly. When immersed into the water, the pure raw soil material is totally defeated and dispersed within less than 60min. And the single-doped modified gypsum soil will also collapse, but duplicate-doped gypsum soil absorbs water and basically reaches the saturation after soaking water 30min later. However, it can maintain 1/3 of the original strength for a long time. The pure raw soil material is totally defeated and dispersed within eroding 15min under the rainfall analogous to the heavy rain, however, the modified raw soil material isn't still basically destroyed within eroding 30min under the rainfall of extra torrential rain, and the water resistance has a greatly enhancement. Mixing desulfurization gypsum can significantly reduce the volume shrinkage of raw soil material, after duplicate mixing fly ash and white lime, the shrinkage further reduces to only about 2.5% of pure raw soil material. Through wetting-drying test, freezing and thawing cycle and anti-carbonation test, compared with the pure raw soil material, it is shown that weathering resistance of the modified material has a great improvement. Test also analyses the thermal performance and reclamation performance of the raw soil material which is modified before and after, and the results indicate that the modified raw soil materials will not deteriorate the insulation and moisture performance and reclamation performance.