Mechanical Properties And Microscopic Mechanism Of Rice Husk Ash-cement Solidified Sludge

Nowadays,china pays more and more attention to renovation and improvement of the environment,but the large amount of sludge accumulated in the construction,river desilting and other projects,which cause environmental pollution and occupies the land resources.Because of its high moisture content and compressibility,it can only be used as engineering soil after certain solidification treatment.The traditional cement solidification technology has caused more pressure on the environment,and a more environmentally friendly and effective solidification technology is urgently needed.In addition,with the advancement of industrialization,a large amount of waste was generated and discharged into the environment.Biomass power plants use rice husk to generate electricity,and produce more than 3 million tons of rice husk ash per year.Its low utilization rate leads to a large amount of accumulation,encroachment land,damage to soil and water environment,which urgent resource utilization is needed.Based on the ecological civilization concept of complying and protecting nature,the technology of rice husk ash and cement solidification of sludge was proposed by adopting the idea of " the Concept of Waste Control ".The main findings are as follows:(1)The basic physical,chemical and mechanical properties of raw materials were studied by means of compaction test,laser particle size analyzer,X ray fluorescence spectrometer and X ray diffraction,which laid a foundation for the experimental study of rice husk ash-cement soil.(2)In order to study the strength characteristics of rice husk ash-cement sludge,the compaction and unconfined compressive strength test were carried out,and compared with ordinary cement soil.The results show that the addition of rice husk ash significantly improved the strength of sludge solidified.The strength and toughness of rice husk ash-cement soil are much better than that of ordinary cement soil.Considering the influence of rice husk ash content and age,the strength prediction model of rice husk ash-soil-cement was established.For the sludge used in this paper,there is an optimal mixing amount of 15% rice husk ash with 8% cement with maximum strength.(3)Based on the scanning electron microscopy,nuclear magnetic resonance and X ray diffraction experiments,explore the rice husk ash-cement soil microstructure,pore characteristics,mineral composition.On this basis,the solidification mechanism of rice husk ash-cement soil was analyzed,and the microscopic evolution mechanism model of rice husk ash-cement soil was proposed.(4)Through the undrained triaxial test,the shear strength characteristics and failure modes of rice husk ash-cemented soil with the optimal content of 15% rice husk ash and8% cement were studied under different confining pressures and ages.The strength and deformation characteristics of rice husk ash-cement soil under triaxial condition were revealed through stress-strain curves and shear strength parameters...