| With the development of construction industry and the acceleration of urbanization,a large amount of construction waste such as waste brick and abandoned concrete is generating by dismantling brick structure buildings.More money is spent,and at the same time the environment is polluted seriously by dealing with and stacking the construction waste.A variety of social,economic and environmental benefits are attached to the new type of wall materials produced by construction waste,which conformed to our country's sustainable development strategy.The complete mechanical theory system of the materials must be established before it is applied in practical engineering.Through experiments and theoretical analysis,the characteristics of the recycled concrete aggregates including waste bricks and the abandoned concrete were studied in this paper.Based on this,the structural column and ring beam were set at the surrounding of the wall used waste brick and abandoned concrete,which formed the composite wall.The mechanical properties of the composite wall were researched.That provide theoretical basis for the promotion and application of waste bricks and recycled concrete used as one of new wall materials.The main contents are as follows:(1)The experiment researched on the performance of the waste brick and recycled concrete aggregates and the mechanical properties of the recycled concrete.The test indicated that waste bricks and recycled concrete as coarse aggregate and fine aggregate,the surface is rough,the porosity is slightly larger;the apparent density and the bulk density are lower,but the water absorption and the moisture content are slightly larger,compared with the natural aggregate.So when the recycled concrete is mixed with waste brick and recycled concrete,the aggregate should be pre-wet to ensure the stability of the water cement ratio.The work ability of recycled concrete used with waste brick and abandoned concrete is slightly worse,the compressive strength and the elastic modulus are also slightly lower,compared with ordinary concrete.(2)The seismic performance of the composite wall composed by waste brick and recycled concrete was researched under the constant vertical load.The seismic performance indicators of the composite wall included the capacity of shear bearing,the failure modes,the hysteretic behavior and the skeleton curve are studied.The results showed that the seismic performance and the ductility of the composite wall are improved effectively by the structural columns.On the basis of the quasi-static test,the impact factors of seismic performance in the wall are analyzed in detail.The formula for seismic shear capacity that is suitable for composite wall used waste bricks and recycled concrete is proposed.The calculation results by the formula are agree well with the test results.(3)On the basis of the pre-test,combined with practical engineering and targeted common wall types,the performance of the composite wall was simulated under the vertical and horizontal forces using the finite element software to establish the simplified models.The wall is analyzed with nonlinear finite element under combined forces state.The occurrence and development of cracks in the composite wall,the anti-side bearing capacity and deformation were analyzed.And the calculated results are in good agreement with the experimental data.(4)Combined with the experimental data and "uniform standards of structural reliability design "(GB50068-2001),the recommendations of design parameters and strength index,bearing capacity calculation,structural requirements and anti cracking of the composite wall composed by waste brick and recycled concrete are made.At the same time,the recommendations of production quality control and construction of the recycled concrete used the waste brick and abandoned concrete are also proposed.Those are provided scientific basis for the promotion of applications and the development design specifications of recycled concrete with waste bricks. |
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