Study On Physical And Mechanicai Properties Of Admixture With Vanadium Slag And Its Shrinkage Compensation Of Concrete

Research and master characteristics of vanadium slag fully.it is one of the important tasks of energy-saving emission reduction to develop efficient utilization in iron and steel industry.The thesis has systematically studied the classification, the physical and chemical properties、mineral composition、volume stability and cementitious activity of vanadium slag from XinYu, discussed the effect of using vanadium slag as admixture on cementitious property,researched concrete compressive strength both when vanadium slag is singly added as admixture and when vanadium slag is double added with fly ash as admixture.To choose the optimum fineness of vanadium slag,to mix vanadium slag and fly ash to prepare shrinkage compensated admixture according to a certain mix proportion.research the influencing law of admixture on strength and shrinkage compensation of concrete.the main conclusions are as follows:(1) Density of vanadium slag is3.06-3.10g/cm3,fineness is124-150m2/kg.the main chemical components:CaO、SiO2、MgO、Al2O3、Fe2O3,the content of CaO is57%～60%in vanadium slag.so it is called high calcium vanadium slag.which is alkaline slag.the main mineral composition:dicalcium sillicate (2CaO·SiO2)、calcium sillicate(CaO·SiO2)、periclase(MgO)、tricalcium aluminate(3CaO·Al2O3) garnet(3CaO·Al2O3·3SiO2)、RO phase.vanadium slag contains f-CaO and periclase, which have adverse effects on volume stability of admixture by vanadium slag,it could alleviate volume stability problem through ball-milling technology.(2) Vanadium slag has a certain cementitious activity, the activity of admixture by vanadium slag increases as fineness increases.The fineness of vanadium slag has a greater influence on late strength than early strength. Grindability of dry vanadium slag is better than wet vanadium slag.after vanadium slag is ball-milled in the same fineness condition,28-day activity of admixture by dry vanadium slag is lower than that of wet vanadium slag,28-day activity of mixed admixture is higher than that of single admixture.With the fineness increases, water usage for standard consistency and setting decreases first and increases then, there is a turning point. (3)The more quantity admixture by vanadium slag insteads of cementitious material,the higher compressive strength of concrete with admixture by vanadium slag is.But the compressive strength of concrete with the original vanadium slag is far lower than that of pure cement concrete. When the dry mixed vanadium slag is grinded in10min, the fineness reaches to669m2/kg,concrete compressive strength advance insignificantly,when admixture insteads of30%of cementitious materials,28-day compressive strength of concrete with admixture by vanadium slag exceeds pure cement concrete12.2%. The compressive strength of concrete by vanadium slag double added with fly ash is higher than that of concrete by vanadium slag singly added as admixture.When the replacement of vanadium slag and fly ash are24%and6%, its concrete compressive strength exceeds that of concrete with30%of fly ash,which is singly added as admixture.and exceeds that of pure cement concrete12.5%.double admixtures show excellent concrete strength level.(4) Using the proportion of10%.18%.72%of gypsum、fly ash、dry mixed vanadium slag respectively,to prepare shrinkage compensated admixture,when admixture insteads of10%and20%of the cementitious materials,both of28-day concrete compressive strengths exceed that of pure cement concrete.there is a certain shrinkage compensation performance of concrete.when admixture insteads of20%of the cementitious materials,38-day shrinkage decreases75%compare to that of pure cement concrete,concrete keeps not expanding and contracting generally, curbs the autogenous shrinkage of concrete effectively.(5) The leaching toxicity. corrosivity. radioactivity of vanadium slag conform to the standard requirement totally, and vanadium slag can be applied to building materials.