Analysis Of Thermal-mechanical Properties Of The Glazed Hollow Bead Recycled Ceramic Concrete Materials

Environment and energy have always been the focus of people's attention,the rapid development of the construction industry and ceramic industry has also brought a series of problems,which causes not only the great pressure on the urban environmental and resources,but also restricts the sustainable development of the urban economy industry.In practical engineering,the waste ceramics are processed into suitable aggregate to make the recycled ceramic concrete,which will find a new aggregate resource for concrete and provide a effective way to utilize the abandoned ceramics.With the policies implementing of energy-saving construction and emission reduction in China.It has become an important topic in civil engineering field to develop a kind of thermal insulation and load-bearing construction material.In this paper,by combining discarded ceramics with glazed hollow bead,a kind of environment-friendly concrete material with load-bearing and thermal insulation is developed,and the results are discussed by experimental research and finite element simulation.Firstly,the discarded ceramics were broken into the aggregates with different radius to replace the natural coarse aggregate and natural fine aggregate on some degree.According to the calculation method for mixture ratio and test method for mechanical properties of ordinary concrete,the effects of different ages and replacement rates on the strength,elastic modulus and thermal conductivity of recycled ceramic concrete are studied,and the feasibility of aggregate replacements is analyzed and discussed.The results show that when natural coarse aggregate is substituted for ceramic coarse aggregate,the strength of recycled ceramic concrete slightly increases and thermal conductivity gradually decreases,which prove that the substitution of ceramic coarse aggregate for natural coarse aggregate is feasible on ensuring strength and material insulation,but the brittleness is more obvious.However,when natural fine aggregate is substituted for ceramic fine aggregate,the strength and thermal conductivity of recycled ceramic concrete both decrease,it is beneficial for ductility and thermal insulation properties of concrete materials.Secondly,the glazed hollow bead with different volume fraction has been mixed intothe recycled ceramic concrete with coarse aggregate,and the influence of the amount of glazed hollow bead on the strength,elastic modulus and thermal conductivity for the recycled ceramic concrete are studied.The results show that the thermal conductivity of the glazed hollow bead recycled ceramic concrete decreases obviously with the addition of glazed hollow bead,the effect of thermal insulation is more ideal,the ductility of the concrete material can be greatly improved,and the problem of brittleness of the recycled ceramic concrete can be effectively solved.Thirdly,the 2D and 3D models for composite materials reinforced by particles with different shapes are established,the effective elastic modulus and effective thermal expansion coefficient of each model are calculated by using the homogenization method and the differences for different models are analyzed,it is proved that the particle shape has a great influence on the local stress distribution of the concrete composite,due to the effect of statistical average of homogenization method,the effective elastic modulus and effective thermal expansion coefficient are insensitive to the shape of the model.In this paper,the finite element model of concrete reinforced spherical particle is established and the effective elastic modulus,effective thermal expansion coefficient and thermal conductivity of materials are calculated by homogenization method.The change regulation of equivalent stress for particles and matrix and the change of cracks location are observed with the increase of the replacement rates of ceramic coarse aggregate,and the failure strength under the ultimate load are determined and are compared with those from experiment.Finally,the recycled ceramic concrete and glazed hollow bead are respectively taken as matrix and particles,the finite element model for glazed hollow bead recycled ceramic concrete is established.The change law of the effective elastic modulus,effective thermal expansion coefficient and thermal conductivity of concrete material are studied by using the homogenization method when the change of the amount of glazed hollow bead,the simulation results are in good agreement with those from experiment.Compared with the ordinary recycled ceramic concrete,the thermal conductivity of the glazed hollow bead recycled ceramic concrete obviously decrease and the thermal insulation performance is great,which is more consistent with the requirement of thermal insulation and energy saving for buildings.