| In the strong appeal of environmental protection in the twenty century,Alkali-activated coagulation materials attracte the attention of scholars in various countries because of its distinctive characteristics of green environmental protection,and it will be occupying an important position in the future of the material market.At present,some developed countries carried out a lot of research with the earlier development of alkali-activated coagulation material.The technology development of alkali-activated cementitious material has reached the practical stage in developed countries.However,the research and application of alkali-activated coagulation materials are still in the initial stage in China.Under this background,alkali-activated coagulation materials as a green environment-friendly materials has a very important and practical significance.In order to effectively promote the popularization and application of alkali-activated coagulation materials in our country,the paper carried out a lot of work about alkali-activated coagulation materials complex design and experimental studies.The main contents and conclusions of the paper are as follows:(1)To carry out the mix proportion design of Alkali-activated coagulation materials for subgrade based on orthogonal test,it was found that the strength test of combined admixture between metakaolin and fly ash was better than that of single blending.The ratio of metakaolin/fly ash is positively correlated with the flexural strength of the material.Excessive increase in the amount of fly ash,lime,gypsum,alkali activator,while reducing the amount of cement will cause a decrease in compressive strength of the material.It is recommended that the ratio of alkali-activated cementitious material for subgrade engineering is 15%of metakaolin,35%of fly ash,4%of lime,4%of gypsum,8%of sodium silicate,4%of sodium hydroxide and 30%of 42.5R ordinary Portland cement.(2)A large amount of mix ratio test was carried out for Alkali-activated coagulation materials in pavement engineering.It was found that sulpho-aluminate cement did have early strength,but it did not contribute much too late strength.While generating early strong performance also cause side effects,such as the material becomes brittle.Only mixed with cement,lime,gypsum,alkali activator does not produce alkali excitation,but will cause material strength system damage due to the micro-expansion of gypsum.The active component of metakaolin can be formed a stable lattice system and a certain intensity under the action of alkali excitation,while the mix ratio content of early strength material should not be too much,otherwise it will cause the strength of the decline.In the alkali-activated metakaolin system,ordinary Portland cement is more suitable than sulpho-aluminate cement,which can produce better strength effect.It is recommended that the ratio of alkali-activated coagulation material for pavement engineering is 20%of sulpho-aluminate cement,10%of lime,10%of gypsum,20%of metakaolin and 40%of 42.5R ordinary Portland cement.(3)The strength and curing leaching tests were carried out for the cuttings produced during the oil and gas field exploitation.It was found that the average COD content in cuttings decreased by 97.3%,the average content of suspension decreased by 95.7%,the average color content decreased by 98.3%,the average oil content decreased by 50.2%and the average hexavalent chromium decreased by 61.5%.Through the corresponding cement curing technology.Although the four curing solutions leachate in the obvious alkaline,the alkalinity of the solidified body does not have a bending,compressive strength adversely affected with reference to its strength test results.Based on the comprehensive analysis of strength test results,curing effect and raw material economy factors,it is recommended to give the alkali-activated cementing material curing ratio is 15%of metakaolin,35%of fly ash,4%of lime,4%of gypsum,8%of sodium silicate,4%of sodium hydroxide and 30%of 42.5R ordinary Portland cement. |
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