Iron Mine Tailings Self-compacting Concrete Compound And Experimental Study On Basic Properties

Iron tailing sand self-compacting concrete (ISCC) is a new kind of concrete material which is compounded by using certain amount of iron tailing sand to replace the natural sand in ordinary self-compacting concrete(SCC) as fine aggregate. It can not only relieve the shortage problem of natural sand, but also can make use of huge amounts of iron tailing sand wastes. This paper gets a good performance SCC by adaptation, then by mixing with certain amount of iron tailing sand and doing numerous adaptations, get the good performance ISCC, lastly make a study of the working performances and basic mechanical properties of ISCC. The major work and conclusions are carried out as follows:1. Refer to the standard of self-compacting concrete to confect SCC, a good performance SCC is gotten, the effects of water consumption and water reducer quantity to the working performance of SCC are studied. The experimental results show that the changes of water consumption and water reducer quantity have similar effects on concrete mixture’s working performance. Only if the water reducer quantity was at the right range will it taken favorable water reducing effect, and it will lead to stratified and bleeding when the water reducer quantity is too much or too little. Slump constant and slump flow increase with the increasing of water consumption and water reducer quantity in SCC, firstly increase fast, then slow down, lastly tend to stop. As a parameter of self-compacting concrete, the slump constant is usually large and be little varied, so it is not suitable for using slump constant to research the working performance of SCC.2. On the basic of the mixing proportion of SCC, use iron tailing sand to replace the natural sand in SCC to research the effect of different replacement percentages on SCC while do not change the other content in mixing proportion, the replacement percentages use20%;40%;60%and80%. The experimental results show that the fluidity of concrete reduces rapidly when the replacement percentage increases. The7day and28day strength of concrete decrease when the replacement percentage increases while the range of strength decreasing is not large. The strength of concrete grows relatively slow in early period but be fast in later period. Once use certain amount of iron tailing sand to replace the natural sand in SCC as fine aggregate, it can not be called SCC any longer because of bad work performance.3. By changing the other part of SCC mixing proportion, research is done by using20%;40%;60%and80%replacement percentages of iron tailing sand to compound ISCC, then the suitable range of replacement percentage in ISCC is explored. The main experiment-al results include that favorable ISCC satisfied self-compacting concrete standard can be obtained by reducing sand content of mixed sand and adopting right quantity of water and water reducer. It is suggested that the replacement percentages of iron tailing sand in ISCC should be low than60%, otherwise the ISCC is easy to be stratified and bleeding and is hard to satisfy the self-compacting concrete standard. The strength of self-compacting concrete which mixed with iron tailing sand is not lower than SCC on the contrary, the strength of ISCC can be higher than SCC under good mixing proportion.4. The influence of sand ratio to the performance of ISCC-40%is studied. There are the highest strength and perfect working performance under43%sand ratio. The appropriate sand ratio of ISCC-40%is43%.5. The strength change of ISCC-40%is studied through changing the quantity of coarse aggregate; gelled material; water and water reducer in mixing proportion under good working performance. The experimental results find that even though the quantity of coarse aggregate is changed the strength of ISCC-40%vary little. The interfacial failure is concurrent with coarse aggregate failure when concrete is broken, it intimates that it is an effectual way to raise concrete strength by raise the strength of coarse aggregate itself.