Recycled Concrete Perforated Brick With Than Its Physical And Mechanical Properties Of Study

With the rapid development of constructing industry and modern industry, the output of construction and demolition(C&D)wastes and the discharge of industrial residue is increasing greatly. On one hand, not only a lot of land is occupied, but also many envorinmental problems and public nuisance are caused by the huge quantity of construction and demolition wastes and industrial residue. On the other hand, the policy concerning encouragment in the development of late-model walling material and restriction in the production of solid clay brick is carried out. With the utility of construction and demolition wastes and industrial residue as recycled resource in producing late-model walling material, their output can not only be reduced, disposal fees be saved, the environmental pollution be decreased, but also recycled resource can be fully used, the consumption of raw building material be economized, good economic benefit, social benefit and environmengtal protection benefit be brought.In this paper, the mixture ratio test of recycled concrete aggregates using 100% crushed concrete rubbles, 1/3 crushed bricks and 2/3 crushed concrete rubbles, 2/3 crushed bricks and 1/3 crushed concrete rubbles and 100% crushed bricks respectively as coarse aggregate and industrial residue as full aggregates is carried out. The effec of the ratio of water and ash, the amount of cement, the ratio of sand and the quantity of fly ash on the properties of recycled aggregates concrete is analysed with the test method of orthogonal design. Based on the chosen mixture ratio after the orthogonal test, recycled concrete perforated bricks of type KP1 are made in the way of extrusion molding by vibration, and the fundamental properties such as the compressive strength, the shrinkage ratio and the freezing-thawing characteristics of concrete perforated brick are tested and discussed in detail. The test results are as follows:1 .For the perforated bricks using construction and demolition wastes as aggregates, the compressive strength increases as the amount of crushed concrete rubbles is added; compared with the perforated bricks made in the factory, the compressive strength of the perforated bricks made in the testing laboratory can be guaranteed because the aggregates used are crushed artificially with little powder, but the compressive strength of the perforated bricks made in factory is played down owing to the aggregates used are crushed by crusher with more powder. As a result, to make sure the compressive strength, the particle diameter should be controlled between 5mm and 10mm.2.The grade of the concrete perforated brick of type KP1 using construction and demolition wastes and industrial residue as recycled aggregates can all reach MU10, and the properties of shrinkage and the freezing-thawing characteristics are satisfactory according to the specifications of Chinese Code(Code for concrete perforated brick JC943—2004).Besides the cost is lower, so it is a potential late-model walling material utilitied in masonry structure instead of solid clay brick and sintering perforated brick.In addition, the analysis of the basic fees about machine-team of producing recycled aggregates is carried out with the example of the collection of recycled aggregates in a small scale and the economic efficiency of the replacement of natural aggregates by recycled aggregates is analysed respectively. All the aspects such as the disposal cost of construction and demolition wastes and industrial residue, the policy concerning encouragment in the development of late-model walling material and restriction in the production of solid clay brick, the environment-protective benefit and the social benifit should be contained in the consideration of the economic efficiency of the recycled concrete perforated brick.