Mechanical Characteristics And Mechanisms Of Dredeged Silt Soildified By Fly Ash And Slag

Dredged silt is a kind of high moisture content, high liquid plastic limit, poor engineering properties of soil, and deal with this is very difficult. Common handling physical methods, such as having a direct landfill, high dehydration, not only the processing cost is high but also will cause secondary pollution of the environment.This experiment adopt two kinds of industrial waste fly ash-slag, under the action of excitation agent sodium silicate dredged silt experimental study. This paper described the current situation of research status quo on dredged silt, fly ash, slag, sodium silicate at home and abroad, analysed the curing material and the curing mechanism of exciting agent, put forward the solidification of dredged silt testing scheme, determined the dredged silt of curing agent and the optimum dosage of exciting agent; explained its curing mechanism and curing effect through macro and micro aspects. In the macro aspect, assessed after solidification of dredged silt strength characteristics and curing heavy metal ability through unconfined compressive strength test, compaction test, California bearing ratio(CBR) test, the test of heavy metal; At the micro aspect, image of electron microscopic scanning and phase analysis by X ray diffraction, microstructure analysis was carried out on the solidified silt. The main contents and results are as follows:1)Determined dredged silt physical properties, through liquid plastic limit test and moisture content test and many other test; Dredged silt, ash and slag were obtained chemical composition and particle size distribution by X fluorescence analysis;2)Through the unconfined compressive strength experiment determined the optimal proportion of various materials such as sodium silicate optimal dosage, the optimal modulus of sodium silicate and optimum dosage of industrial waste and so on, the optimal ratio(mass ratio) of test silt: slag: sodium silicate = 60:40:7, cured 28 d strength of 10.84 MPa. Got the mechanics characteristics of stress-strain relation belongs to the strain softening characteristic;3)Through the compaction, California bearing ratio(CBR) test, determined the relationship between the dry density and moisture content of figure and cuvre of p-s, analyzed the feasibility of after curing material as subgrade filling; The results showed that conditions F36S4, F34S6, F32S8 complyed with the minimum requirements strength of roadbed filler;4)By electron microscope(SEM) and X-ray diffraction ray(XRD) test, analysed pore and products of dredged silt before and after curing, explained the reaction mechanism. By heavy metal precipitation test and determination of heavy metal leaching test of before and after curing, assessd the effect of the dredged silt.