Study On Blast Furnace Slag Non-autoclaved Brick

The blast-furnace slag is a mineral by-product of the iron industry. With the increase of steel output, the first thing to deal with the blast-furnace slag is expanding its varieties and increasing its dosage, especially under the saturated slag market. Therefore, the utilization of slag is a very significant problem.Slag has potential activity, so it can be applied to product building materials through some inspire handling. As the rapid development of construction industry, the demand of new wall materials is large. So using slag to prepare non-autoclaved brick is a good method of slag utilization. Using slag to prepare non-autoclaved brick has several advantages, for example, simple producing process, low consumption and big adding quantity, conforms to the national environmental policy. So it has important economic value and society value.On this study, the water-quenched blast furnace slag was the major raw materials of non-autoclaved brick with other industrial waste like a certain amount of fly ash, heavy slag and a small amount of hydration activity stimulate materials, such as cement, gypsum, unslaked lime. The non-autoclaved brick that meet the national standard was obtained by compacting. The main content and the research results are as follows:1.The formula design of non-autoclaved brick. Choosing the different excitants to carry on the stimulation experiment to the slag powder, the results indicate the best excitant is the mixture composed by unslaked lime, gypsum, cement under the semi-dry process formation condition. Based on the research about the influence of powder and aggregate ratio to the strength of non-autoclaved brick, the best ratio of powder and aggregate is 4:6. And from the results of the influence of powder composition to the strength of non-autoclaved brick, brick has good strength when the slag powder and fly ash are mixed. The results of the influence of aggregate composition to the strength of non-autoclaved brick, show that brick has the biggest flexural strength when the coarse and fine aggregate ratio is 3:7.2. The main production process of non-autoclaved brick. Based on the research about the influence of digestion to the strength of non-autoclaved brick, the results indicated that the digestion is not necessary. And from the results of the influence of curing to the strength of non-autoclaved brick, cured in natural condition and watering several times is the best curing method. The results of the influence of molding pressure to non-autoclaved brick, show that the best molding pressure is 12 MPa.3.The durability of non-autoclaved brick. There is little influence on the drying shrinkage when the variety of aggregate changes. When the aggregate ratio is 1:1, the drying shrinkage of non-autoclaved brick is smaller than the one whose aggregate ratio is 3:7, on the condition that fly ash is added and the proportion of fly ash and slag powder is determinate. And the drying shrinkage of brick has a minimum when the powder and aggregate ratio is 4:6. Adopting different curing methods, the drying shrinkage of brick is minimum under watering maintenance. The non-autoclaved brick shows good anti-freeze capability, and the changes of powder and aggregate have a little influence on the frost resistance. The higher the proportion of, the more serious the efflorescence of non-autoclaved brick. The carbonization coefficient of brick is the highest when the slag powder and fly ash ratio is 1:1.