Study On Concrete Perforated Bricks Made Of Recycled Aggregates And Mechanical Behavior Of Its Masonry Under Loading

In China, a large quantity of construction, demolition and industrial wastes is produced every year, and the disposal and stockpiling of these wastes has become a severe social and environmental problem in the territory, so recycling of these wastes, which has social, economic, environmental benefits, is becoming more and more important. The recycling and the application of concrete perforated brick using recycled aggregates not only resolve the numerous heaped construction and demolition (C&D) wastes, but also provide a method to resolve a serial of problem brought by the forbidding of clay brick. However, a as a kind of new wall material, before being used in the actual engineering, an integrated dynamic theory system about concrete perforated brick using recycled aggregates should be drown up. In order to popularize concrete perforated brick using recycled aggregates, some experimental research on this new material using constructional and industrial wastes is made. The main contents of this dissertation are listed as follows:1. Compared with natural aggregate, the accumulation density of recycled aggregate is lower, the water absorption is higher, and the surface is crude. By orthogonal tests, the influence of water cement ratio, unit water and sand ratio on the compressive strength of concrete perforated brick using recycled aggregates is analyzed. Mixture ratio of concrete perforated brick using recycled aggregates is made through the orthogonal tests on 3 type recycled aggregate and 27 mixture ratio, and the relationship between the strength of concrete perforated brick using recycled aggregates and aggregate type is analyzed, at last, the relationship between the test block strength and the compressive strength of perforated brick is presented. In addition, the experimental studies for compressive strength, shrinkage, freezing-thawing and other physical performance of concrete perforated brick using recycled aggregates are carried out. At one time, the strength of concrete perforated brick using recycled aggregates both in site and in laboratory is compared. It is showed that the shrinkage strain of concrete perforated brick using recycled aggregates is relatively small, and the freezing-thawing performance satisfies the requirements specified in the Chinese National Standards. In conclusion, the concrete perforated brick using recycled aggregates could become a new-type bearing wall material instead of fired clay common bricks.2. Based on the compressive test of concrete perforated brick masonry using recycled aggregates, the influence of aggregate type, brick strength, mortar strength etc factors to the force behavior, failure mode, occurrence development of the crack, crack capacity and deformation capacity is analyzed systematically. The compressive stress-strain whole curve formula of concrete perforated brick masonry using recycled aggregates, elasticity modulus and poison ratio formula are achieved in this paper. And the theoretical formula and practical formula of the compressive strength about concrete perforated brick masonry using recycled aggregates are established. At the same time, the computational results of both formulas coincide with the experimental result very well. In this paper, according to the contrasting test of concrete perforated brick masonry using recycled aggregates and concrete perforated brick masonry using nature aggregates, it is shown that concrete perforated brick masonry both using recycled aggregates and nature aggregates has similar developing feature of crack, but the brittle characteristics of concrete perforated brick masonry using recycled aggregates is significantly more than that using nature aggregates. And these two types of concrete perforated brick masonry have approximate limit loads. Thus it can be seen the same compressive strength formula for these two types of concrete perforated brick masonry is established on the basis of experimental results.3. On the basis of the shear test of concrete perforated brick masonry using recycled aggregates, the influence of aggregate type, mortar strength etc factors to the force behavior, failure mode, strength and deformation of concrete perforated brick masonry using recycled aggregates is analyzed systematically. The practical formula of the shear strength about the perforated brick masonry is established, which coincides with the test results. And the value of shear modulus is put forward basing on the analysis of shear stress-strain whole curve of concrete perforated brick masonry using recycled aggregates.4. Experiments on the seismic behavior about 7 walls under the low cyclic loadingsare carried out, and the bearing, failure feature, hysteretic property, skeleton curve, stiffness of walls are discussed. Now it is showed that the seismic behavior of the walls with constructional column is improved by a long way compared with the walls without column. Also, the factors influencing the seismic performance are analyzed in depth. In the final, a formula about the shear bearing of the walls with constructional column is suggested, and it can be seen that the calculated results using the suggested formula accord with the experimental results commendably.5. Nonlinear finite element analysis for combined shear-compression action behavior of walls is made by ANSYS program in this dissertation. The crack patterns, the development condition, the bearing capacity and the deformation are all simulated, which coincide with the test results.6. According to the and the experimental results in this paper, the design parameters, the bearing capacity, the ration of hight to sectional thickness of wall or column, the structure measures and the crack control measures about concrete perforated brick masonry using recycled aggregates are advised. At the same time, the control about construction quality of concrete perforated brick using recycled aggregates is also put forward. As we know, all we have done provide scientific support for the development of the industrial application of concrete perforated brick masonry using recycled aggregates and the setting up of relevant design standard.