Study On Mechanical Properties And Durability Of Alkali-activated Ultra-high Performance Concrete With Silicomanganese Slag

Alkali activated cementitious material is a kind of green cementiting material produced by the silica aluminum waste and other substances under the action of alkali activator.Silicon manganese slag is a large solid waste discharged from the ferroalloy industry in China,which pollutes the environment and occupies resources.Based on the characteristics of alkali activated cementiting materials and the silicon aluminum composition inside the silica manganese slag,this paper discusses the methods of preparing the polymer mortar and the alkali-excited ultra-high performance concrete based on the silica manganese slag.The influence of different factors on the properties of the geopolymer mortar and the alkali excited super high performance concrete and the micro mechanism analysis are studied.The conclusions and innovations of the paper are as follows:(1)The high strength geopolymer mortar with the silica manganese slag with compressive strength over 80 MPa and the alkali-excited ultra-high performance concrete with compressive strength of more than 132 MPa were prepared under the condition of steam curing by grinding and alkali activation.The two materials have good frost resistance,strong acid resistance and excellent mechanical properties.(2)The influence of the factors such as the amount of silicon manganese slag,the modulus of water glass and the amounts of quartz sands on the mechanical properties and working performance of the high strength geopolymer mortar based on silica manganese slag was studied.The strength development of the super high performance concrete excited by the base of silicon manganese slag was investigated under different steel fiber dosage,grinding time and retarder types.The results show that the high strength geopolymer mortar and alkali-excited ultra-high performance concrete with 10% silicon manganese slag and modulus of 2 are the best.The more the content of manganese silicon slag was,the less the strength of the test was,and the better the fluidity and the longer the setting time was due to the insufficient activity.The high modulus of water glass was beneficial to the production of hydration products in materials.After replacing quartz sand with silica slag,a small amount of replacement had little effect on strength weakening,but the strength of the replacement with large amount of silica decreased obviously because of the low content of silica.For the ultra-high performance concrete excited by the base of silicomanganese slag under different factors,the steel fiber was beneficial to the strength development and toughness improvement and reduce the fluidity of the material.The grinding time of the slag determines the active substances inside the slag.When the grinding time increases,its activity will be fully developed and the performance of concrete will be improved.The working and mechanical properties of the materials were directly controlled by different retarders.(3)The durability of the concrete excited by the base of silicomanganese slag base was studied,such as frost resistance and acid resistance.It was found that the appropriate amount of steel fiber could improve the frost resistance and acid resistance of the material,which proved that the appropriate amount of steel fiber maked the concrete structure fully developed and the structure is more compact;the grinding time promotes the activity of silicon manganese slag;the hydration products increased in the reaction process,and the corresponding performance was improved;under different retarder types,the frost resistance and resistance of the test group were improved The acidity was good,the influence law of strength,quality and mechanical properties was well matched;the addition of silicon manganese slag slowed down the hydration process of alkali-excited materials,and the frost resistance and acid resistance were decreased.(4)The microstructure and hydration process of the super high performance concrete excited by silica manganese slag,and the high strength geopolymer mortar with silicomanese slag were studied.The results of the phase of the high strength geopolymer mortar and alkali-excited ultra-high performance showed that the higher the strength,the denser the structure and the even and dense distribution of hydration products,the higher the strength of the materials,the denser the structure and the even distribution of hydration products.The results showed that the micro morphology of the mortar was plate.Cementitious materials were formed by three dimensional network gel network under the action of alkali excitant by breaking down bonds and condensation.The matrix and steel fibers were tightly bonded.Therefore,the mechanical properties and durability of cementitious materials were excellent.