The Study For Mechanical Property And Constitutive Relationship Of Recycled Insulation Concrete

Recycled aggregate thermal insulation concrete(RATIC)is one new kind of load-bearing concrete.It combines the advantage of resource-saving and energy-saving and reflects the characteristics of low-carbon environment and sustainable development.Utilization of RATIC could realize the cyclic utilization of concrete and make the duration of thermal insulation system same as structure system.What's more,it could decrease the construction cost of recycled aggregate concrete,accordingly,and obviously increase the performance-price ratio.At the meanwhile,it promots the utilization of recycled aggregate concrete feasibly.This new concrete provides the new way for sustainable development of recycled aggregate concrete.Experiments is carried out,with C30 glazed hollow bead insulation concrete as the basic mixture ratio,recycled aggregate replacing natural aggregate 0%,30%,50%,70%,100%.The following works were carried out as the first study of recycled aggjegate thermal insulation concrete:(1)The research for mechanical property of recycled aggregate thermal insulation concreteExperiments on cubic compressive strength,axial compressive strength,splitting strength and flexural strength of recycled aggregate thermal insulation concrete with different replacement of RCA were carried out.Through the tests,The damage process and form have been understood,the influence of recycled aggregate replacement to strength has been analyzed and revealed,at last,the quantitative relation among various strengths and the cubic compressive strength were determined with regression analysis,and the result was Compared with that of ordinary concrete,glazed hollow bead insulation concrete,recycled concrete.(2)The stress-strain curve of recycled aggregate thermal insulation concreteExperiments on Uniaxial compression constitutive relationship of recycled aggregate thermal insulation concrete were carried out,Through the tests,The damage process and form have been understood,Stress-strain curve was determined and analyzed,at last,Stress-strain curve were matching by using the method of Matlab,so that the relative parameters can be acquired and the representation of complete curve can also be established.(3)The analysis of the stress-strain curve of recycled aggregate thermal insulation concreteThe relationship between elasticity modulus,poisson's ration,peak strain,ultimate strain,compressive strain density,brittleness index and recycled aggregate replacement was researched,the stress-strain curves with different replacement of RCA(0%,30%,50%,70%and 100%)were analyzed,lastly,the stress-strain curves of ordinary concrete,glazed hollow bead insulation concrete,recycled aggregate thermal insulation concrete were contrasted.Through the experiment and the post-processing and analysis of data,the conclusions received are as follows:(1)Damage model of recycled aggregate thermal insulation concrete belong to“Strong(mortar)" package "weak(recycled aggregate)" model,failure belong to shear failure of recycled aggregate or bond failure of interface on aggregate and mortar;recycled aggregate replacement increased,various strengths overall decline,but downtrend of various strengths is obvious when recycled aggregate replacement is 0%?50%,strength trend to stability when cycled aggregate replacement is over 50%.cubic compressive strength,axial compressive strength,splitting strength and flexural strength respectively is 8.8%?9.4%?8.8%?3.1%lower than reference concrete when cycled aggregate replacement is 50%.(2)Damage model of recycled aggregate thermal insulation concrete belong to oblique shear failure when uniaxial compression was carried out.Crack extend from middle to both ends of block,gradually forming inclined crack,and quickly through the whole section.Tilt angle for principal inclined crack of block is 60°?73°,and Tilt angle increase with increase of recycled aggregate,it showed friability of recycled aggregate thermal insulation concrete is big,that is plastic deformation of recycled aggregate thermal insulation concrete is poor.(3)Comparison of stress-strain curves of recycled aggregate thermal insulation concrete with different replacement of RCA indicated that as recycled aggregate replacement increased,slope for upward section of stress-strain curve gradually decreases,peak point of curve declines and moves to right,it showed that elasticity modulus of concrete reduced;downward section of stress-strain curve became,to steepen,ultimate strain decreased,it showed Concrete became brittle.(4)Peak strain is between 1.5×10-3 and2.3×10-3,ultimate strain is between 3.0×10-3 and 3.5×10-3 elasticity modulus is between 2.69(×10-4N/mm2)and3.32(×10-4N/mm2).Elasticity modulus and ultimate strain of recycled aggregate thermal insulation concrete showed a trend of decline,peak strain and brittleness index had a trend of increase,poisson's ration changed non-significantly,when recycled aggregate replacement increased.