Preparation And Properties Of Titanium Slag Sinter-free Lightweight Aggregates

There are abundant of high titanium slag in southwest China.It cannot be directly used to product cement and prepare concrete,because of its high titanium content,very stable containing titanium mineral phase and low activity.A new sinter-free lightweight aggregate(SLWA)has been prepared using titanium slag(TS)as main raw materials by alkali activated technology in this study.The properties of alkali activated titanium slag(AATS)with different dosage of water glass,water to binder ratio(W/B),curing temperature and curing time were studied.According to the experiment result,hydrogen peroxide(HP)and aluminium powder(AP)were used as air-entraining agents respectively,SLWA could be obtained by using disk granulator apparatus.The lightweight aggregate concrete was prepared by using titanium slag sinter-free lightweight aggregate,and the properties of the concrete were be studied.The results showed that water glass was a good alkaline activator for titanium slag.The compressive strength increased with increasing content of water glass and decreasing of W/B curing at temperate condition,and the better AATS could be obtained by curing at 90℃ for 12 h.The 700、800 and 900 density level lightweight aggregates of the Chinese National Standard GBT17431.2-2010 have been prepared by both of air-entraining agents.The technology of aluminium powder used as air-entraining agent was simple and easy to operate,the bulk density of aggregates was lighter,the more open pore was obtained and the absorption was increased.Compared to the air-entraining process of aluminium powder,Hydrogen peroxide air-entraining process was complicated,the technological requirements was higher,the aggregates with smoother and more dense outside surface,uniform internal pores,fewer open pore and smaller absorption,could be obtained.The SLWA with higher cylinder compressive strength and lower 1h water absorption prepared by using HP were observed compared to that of SLWA by using AP in a similar bulk density level.The 800 density level SLWA,PO425 cements and medium sand were used to prepare lightweight aggregate concrete.The LC20 lightweight aggregate concrete with the bulk density of 1700 kg/m3 and 1800 kg/m3 and The LC25 lightweight aggregate concrete with the bulk density of 1900 kg/m3 could be obtained by adjusting the volume of sand ratio and W/B.The Interfacial transition zone of the concrete also be studied,there are some different structures compared with the normal aggregate concrete.