Study On Stochastic Damage Constitutive Relation Of High Strength Recycled Concrete

The depletion of natural resources and ecological destruction increasingly serious,as the development of urban and rural construction in China is excessively rapid.The research shows that recycled concrete can solve the problem of abandoned concrete technically.Mechanical properties are the key problem restricting the development and application of recycled concrete,so the development and application of high strength recycled concrete has become a new hotspot in the engineering field.However,the damage constitutive theory of high strength recycled concrete is less studied at present.In order to popularize recycled concrete in the future,the damage mechanism of high strength recycled concrete needs further study.Based on the existing concrete damage theory combined with the characteristics of high strength recycled concrete,this paper will carry out the following research;A series of mesoscale models were established to simulate the mesoscale structures of ordinary strength concrete,ordinary strength recycled concrete and high strength recycled concrete respectively.Based on the models,the damage fracture processes were simulated and the corresponding damage constitutive relations were deduced.High strength recycled concrete and ordinary concrete of different strength are prepared.The mix ratio of high strength recycled concrete is introduced.Factors such as the replacement rate of recycled aggregate,cementitious materials,waterbinder ratio,cement materials and water-reducing agent materials were analyzed to study their relationship with the mechanical properties of high-strength recycled concrete.By using CT scanning test,the internal damage change of concrete test block is observed and the damage evolution law is analyzed.Based on the damage characteristics of reclaimed aggregate and mortar in high strength recycled concrete,the damage process of high strength recycled concrete is simulated by using a meso model,and then the damage constitutive relation was established according to the conservation of energy.The research results of this paper can provide some theoretical support for the application of high strength recycled concrete,and is conducive to the popularization and use of high strength recycled concrete,and provides the mechanism of internal damage and failure for the study of high strength recycled concrete.It provides a reference for the follow-up research and further popularization of high strength recycled concrete.