Experimental Research On Mechanical Properties And Shrinkage Properties Of Broken Pebble Recycled Concrete

In order to respond to the strategic goal of sustainable development and build a civilized Handan,this article focuses on the use of broken pebbles and waste concrete building materials in Handan.Due to the acceleration of urbanization in my country and the increase in the production of concrete materials,a large amount of rock resources are needed to prepare natural coarse aggregates.The rock has been over-cultivated and the resources are scarce,which severely damages the natural environment,while broken pebbles are rarely used by humans.There are many rivers in our country,and stable chemical properties,hard tissue and abrasion resistant rivers spread across the river bed and both sides.The crushed natural coarse aggregate is used to prepare concrete and relieve the shortage of rocks.On the other hand,a large amount of construction waste is generated in the demolition and reinforcement of existing buildings.Most of the construction waste is waste concrete,which cannot be reasonably arranged,which not only pollutes the environment but also affects the appearance of the city.Based on the above two problems,this paper studies the recycled concrete with broken pebbles and waste concrete in Handan area.Taking the recycled coarse aggregate made of industrial waste fly ash and waste concrete as variables,The effect of the content of the flying machine(0%,10%,20%)and the ratio of recycled coarse aggregate(0%,15%,30% 45%)to the mechanical properties and the production of recycled gravel concrete were examined.Effect of contraction performance.The research content and completed work of this article are mainly as follows:(1)This paper introduces the present state of research on recycling of concrete performance in Japan and abroad.Basic physical performance tests of recycled coarse aggregates from rubble and waste concrete are tested in the soldered area to obtain rubble and recycled coarse aggregates.The bulk density,apparent density,crush index,water absorption rate(24h)of the material;finally,the type of test and the number of test pieces required for each test are explained.(2)Fracture and failure processes of recycled concrete were investigated and analyzed.Based on test data,a model has been developed to calculate axial and cubic compressive strength of recycled stone concrete.Theoretical foundation of the technical application of concrete regenerated from pebbles.(3)The elastic modulus test and ultrasonic wave velocity nondestructive testing of recycled concrete with broken pebbles are carried out.Determine the law of change in the modulus of elasticity of recycled coarse aggregate by fly ash content and exchange rate.Pebble draws the stress curve of damaged recycled concrete.Determine the modulus of elasticity,compression strength,and ultrasonic velocity calculation of the basis of damage to recycled concrete.The shape of a small stone is broken.(4)Shrinkage tests of recycled concrete with broken pebbles of different ages(3d,7d,14 d,28d,45 d,60d,90 d,120d,150 d,180d)were carried out.The change rule of the replacement rate of recycled coarse aggregate,and based on the BS EN shrinkage deformation prediction model,the shrinkage deformation prediction model of broken pebble recycled concrete is established,which takes into account the replacement rate of recycled coarse aggregate and the amount of fly ash.