Influence Of Construction Waste Regenerated Fine Powder On Properties Of Raw Soil Materials

Raw soil materials are still in use today due to their good thermal performance,adjustable humidity,and convenient access to materials.However,after experiencing complex climates such as low temperature and rainfall,mechanical properties and durability will deteriorate.There have been studies aimed at this problem by using cement,lime,gypsum and other materials to improve the performance of raw soil materials,but when the content of these materials is too high,not only will the performance of raw soil materials be excessive,but also the construction cost will be too high.Considering that the actual use of raw soil materials does not require high strength,generally 4MPa～5MPa,so the regenerated fine powder with activity is mixed into raw soil materials,and it is expected that the fine powder can exert better activity,chemical reaction occurs,and condensation is formed.Glue and other products play a role in improving the properties of raw soil materials,and provide theoretical support for the use of recycled fine powders mixed with raw soil materials through the study of the mechanism of differences in mechanical properties and durability.Therefore,in this experiment,the research content is to improve the performance of raw soil materials and the mechanism of mixing recycled fine powder into raw soil materials.Two types of recycled fine powders,RBP and RCP,are prepared.The blending ratio and the level of fine powder are used as variables,and a single-mixed recycled fine powder is designed.Experiments were carried out on the raw soil materials mixed with recycled fine powder and cement.The rammed molding was used to study the mechanical properties,durability and mechanism of action.The main conclusions are as follows:(1)Raw soil materials mixed with regenerated fine powder alone cannot improve the performance of raw soil materials,but controlling the level I RBP content at 2% to 6% has little effect on the mechanical properties and durability of raw soil materials.Used in areas with stable climatic conditions,it has a positive effect on increasing the utilization rate of regenerated fine powder and reducing project construction costs.(2)The raw soil material mixed with regenerated fine powder and cement,when the level I RBP content is 6%～14%,and the level II content is 10%,it can further improve the mechanics on the basis of the raw soil material mixed with cement alone.Performance and durability can be used in areas with complicated climatic conditions.(3)Among the raw soil materials mixed with regenerated fine powder,RCP due to weak chemical reaction,high water demand ratio,poor particle shape,resulting in shrinkage cracks,resulting in poor clay system stability and micro-aggregate effect.When the RCP content is higher than 6%,the “stent-inlaid semi-cemented” structure of the rammed soil will be destroyed.(4)Among the raw soil materials mixed with recycled fine powder and cement,RBP and cement can continue to react on the basis of cement hydration reaction to generate more gel substances such as CSH,and the amount of RBP in level I is 6%～ At 14%,the consolidation and strengthening effect of the “stent-inlaid microporous semi-cemented” structure of the rammed soil is the best;while RCP has a large number of inactive particles and a high water demand ratio,which leads to weak chemical reaction with cement and suppresses it.The cement hydration reaction and the formation of the clay system will destroy the "scaffold-embedded semi-cemented" structure of the rammed soil when the I/II grade RCP content is higher than 10%.