Experiment Research On The Red Mud And Fly-ash Aerated Concrete As A New Insulating Wall Material

Red mud is the largest solid waste generated during aluminum production from bauxite. With the increasing of alumina output, the amounts of Red mud keep growing; it takes the massive lands in the stack process, but also has caused the serious pollution to the natural environment, and the waste to the natural resource. The appearance and development of new building material is good news to thousands of various industrial wastes residue of which effective recycling can realize a win-win of environmental and economic benefits. This paper select the Bayer process red mud , low grade fly-ash, dry process calcium carbide sludge, activation and so on for main raw material to produce Aerated Concrete, which was developed and studied as new wall material.At the first, the experiment studied the linear dependence between compressive strength, dry density of red mud aerated concrete cube and a variety of gelled material, the ratio of nutriment. The results shown that, by means of regression analysis, it existing significantly linear correlation between compressive strength, dry density of red mud aerated concrete cube and a variety of gelled material, the ratio of nutriment. The main factor of influencing compressive strength concrete cube was the ratio of nutriment, because of the characteristics of stomata and the distributions of water in aerated concrete. The main factor of influencing dry density concrete cube was the admixture of red mud, because the alkali content of red mud influenced basicity in slurry, and the producing gas of aluminum. on this basis, according to the influence of radium activity on red mud, aerated concrete decreased the content it, meanwhile, mixed the calcium carbide sludge that was industrial waste residue of strongly alkaline, which effectively aroused aerated concrete in pozzolanic effect of fly-ash. It studied the factors of all kinds of level influence on the aerated concrete performance of products. The results shown that when content of red mud has below 20 percent the ratio active inspection of aerated concrete could achieve the standard GB6566-2001"Building Material Radionuclide Limits", which the inside illuminate index was 0.76, and the outside illuminate index was 0.76. Finally, analyzed and coMPared with various kinds of curing technique on red mud aerated concrete cube shown different maintenance technique directly effected the saturated compressive strength, later development and dry density on performance of products. Through testing aerated concrete thermal performance, the result of experimentation shown that, the coefficient of thermal conductivity of red mud aerated concrete, thermal resistance and dry density was 0.24W/m·K, 1.00m2·K/W, and 864kg/m3, so using thin red mud aerated concrete could obtain bigger thermal resistance, it just proved that red mud aerated concrete had favorable performance of thermal insulation.At the last, through the samples of SEM analysis shown that hydration products of red mud aerated concrete caused main mineral that was Ettringite of needle bar, which contributes mostly to the strength of the aerated concrete. At the same time, there were gelatinous hydration products with the form of fibrous, netty CSH.