Bending Performance Test And Finite Element Simulation Of Recycled Micronized Concrete Laminated Slabs

The utilization of construction solid waste including recycled micronized powder is an important research direction for the green development of the construction industry.Recycled micronized powder is a new,environmentally friendly and economic construction solid waste material that can be a good substitute for cement or fly ash,and its utilization can improve the utilization rate of construction solid waste.At present,the research on recycled micronized powder is basically at the stage of material properties,and the research on the basic mechanical properties of engineering components prepared by it is rarely reported.Reinforced truss concrete laminated slab is a common flexural member,and it has been widely used in construction because of its high mechanization,short construction time,energy saving and environmental protection.Because:on the one hand,casting steel laminated slabs with recycled micronized concrete can obviously improve the utilization rate of construction solids;on the other hand,and no reports on the application of recycled micronized powder in concrete laminated slabs have been found.Therefore,this paper focuses on the effect of different micronized powders on the flexural properties of steel truss laminated slabs in order to prove the feasibility of their application in practical engineering.The overall task of this paper is to investigate the effect of the type and substitution of recycled micronized powder on the flexural performance of laminated slabs by testing and simulating laminated slabs prepared by single/mixed replacement of cement and fly ash with20%of recycled micronized powder.The design of the test program(material and structure),the analysis of the test and its results,and the explicit finite element simulation of the bending performance of the slab were completed.The above work is an organic and progressive whole,as follows:(1)An experimental study of the mechanical properties of the recycled micronized powder was conducted,followed by the design of the dimensions,reinforcement,concrete ratio,loading scheme,and measurement scheme for the five plates;(2)Then the tests of four-point bending slabs were completed,and the test results of crack development process and morphology,mid-span load-displacement curve,load-deflection curve,and reinforcement/concrete strain of the specimens were analyzed afterwards;(3)Finally,the explicit finite element simulation of the slab was completed based on the intrinsic structure relationship of the material properties test,and the results of the load-displacement curve,energy time course curve,and tensile damage contour given by the simulation were then used to study the test results comparatively.By analyzing the experimental and simulation results,the following conclusions were drawn:(1)the flexural damage process of recycled micronized laminated slabs is basically the same as that of ordinary concrete laminated slabs,but the cracking load,yielding load and ultimate load P_u are different;(2)When the recycled micronized powder replaces cement,not only will the P_u be reduced to a greater extent,but also the degree of influence of different recycled micronized powder on the plate P_uis different,and the reduction of P_u is only as high as 13.0%when comparing with the ordinary plate;when the recycled micronized powder replaces fly ash,the degree of P_ureduction is very limited,and the reduction of P_u is only 3.7%when comparing with the ordinary plate;(3)The P_u given by the simulation is more accurate,and the error is less than 10%when comparing with the test;the load-displacement curve,energy time course curve and tensile damage contour given by the simulation can not only corroborate each other,but also can correctly portray the test results.