Preparation Of High Performance Concrete Mixture With Lead-zinc Ore Tailings From Youxi,Fujian Province

In this dissertation,the lead-zinc ore tailings were used as main material to produce the high performance concrete mixture through the mechanochemistry activation.The pozzolanic property and hydration product of milled lead-zinc ore tailings have been studied experimentally.On this basic,the pozzolanic property and hydration product of several kinds of main mineral in lead-zinc ore tailings were also investigated.Through the mechanochemistry activation,the specific surface area of lead-zinc ore tailings increased from 351.9m2/kg to 795.4m2/kg and that of grinding in the SM? 500×500 experimental mill from 15min to 120min.As the grinding time increased,mineral particles were transferred form big and sharp to small and smooth.After 90min,the mineral particals will be aggregated.The grinding time is determined to 60min by cement motar experiment.The specific surface area of lead-zinc ore tailings at 60min is 595.8m2/kg.Through the double doped C30 pump concrete experiment,Lead-zinc ore tailings can be used to replace 10%amount cementitious materials' admixture A or II fly ash was proved,and the compressive strength of the concrete can still be improved.The replacement amount of cement should not be more than 15%.S95 slag powder is not suitable to be replaced.Double doped C40 pump concrete experiment proved the lead-zinc ore tailings can be used to replace 10%amount cementitious materials' cement through the redution of water content by the addition of concrete slump,and the admixture A can be fully replaced by lead-zinc ore tailings in this system.The chloride ion penetration resistance,resistance to freezing-thawing and carbonation resistance effects of lead-zinc ore tailings added double doped C40 pump concrete are meeting the standards of JGJT 385-2015.The shrinkage test proved that the lead-zinc ore tailings have inhibitory effect to concrete's self-constriction.The analysis of XRD,SEM,FT-IR,DSC,NMR and the paste specimens experiment proved that the milled lead-zinc ore tailings have got pozzolanic property.The main hydration products of lead-zinc ore tailings are AFt and C-S-H gel.Furthermore,essential minerals of lead-zinc ore tailings just like milled hedenbergite,diopside,epidote and quartz have got pozzolanic property.The main hydration product of milled hedenbergite and diopside are AFt and C-S-H gel.The main hydration product of milled diopside and quartz are C-S-H gel.