Study On Bending Performance Of Core Filled Assembled Lightweight Aggregate Concrete Slab

With the vigorous promotion of the State Council and the successive introduction of local government policies,prefabricated concrete structure buildings have entered people’s vision.Prefabricated concrete structure has the advantages of fast construction speed,short construction period,good economy and environmental protection,etc.It meets the demand of the construction industry market and the requirements of environmental protection.Among them,prefabricated concrete slabs,which are horizontally-stressed members,and the floor system occupy a large proportion in the entire structure,and the traditional construction process is relatively complicated.Therefore,it is necessary to deeply study the new prefabricated floor slab with high bearing capacity,fast construction speed,environmental protection and economy,which has an important impact on promoting the development of construction industrialization.The precast slabs of core-filled assembled concrete slabs studied in this paper belong to transverse hole hollow slabs.The slab side adopts different structural forms.The thickness of the precast slab is the final design thickness of the assembled concrete slab.The prefabricated slab has high rigidity and high bearing capacity.In the case of continuous structure,the core is filled in the hollow and the bending moment reinforcement is arranged in the strip groove,and the concrete is cast to form an assembled whole.In this paper,the mechanical properties of ceramsite lightweight aggregate concrete compared with ordinary concrete,and change the structural form of the panel-side assembled grooves(LC1,LC2).Through manual loading,the bending performance of the filled core lightweight concrete is studied.The main contents are as follows:(1)Design the mix ratio of shale ceramsite light aggregate concrete and test its mechanical properties.conduct mechanical performance tests:The tests show that the apparent density is 36%lower than that of ordinary concrete under the mix ratio proposed in this paper,The compressive strength of the lightweight aggregate concrete cube reached 35.4MPa,which was 7.9MPa lower than that of ordinary mixed concrete.It meets the strength requirements of concrete slabs(LC30)of 35.4 MPa,Through the mechanical performance indicators and the failure form of the tension-compression ratio and the elastic-strength ratio,it is found that the light aggregate concrete configured under this mix ratio is superior to ordinary concrete in terms of crack resistance,ductility and integrity.(2)According to the bending performance test of the filled core prefabricated lightweight aggregate concrete prefabricated slab,the research shows that the cracks of the slab are generated at the flanges under the holes,and they do not develop between the two holes.Moreover,the failure forms of LC1 and LC2 are basically similar.The structural form of the slab side has little effect on the bending performance of the precast slab.Compared with the core-filled prefabricated precast slabs(N1,N2)using ordinary concrete,the ultimate bearing capacity is 8%,a little difference.(3)The formulas for the core-filled assembled lightweight aggregate concrete slabs before cracking are calculated by formulas in the current "Code for Design of Concrete Structures"(GB50010-2010)and "Code for Design of High way Reinforced Concrete and Prestressed Concrete Bridges and Culverts"TGD62-2004 The theoretical calculated value of the stiffness after cracking has been compared and analyzed,and a correction coefficient K related to the hollow ratio is proposed,and the calculation formula of the stiffness of the concrete slab is revised.(4)Design the construction flow chart of the core-filled assembled concrete slab,design 4 key points of quality control,and propose strengthening measures for the key points of quality control.(5)Using the ABAQUS finite element software simulation,the cracks,yields,failure stresses,crack development diagrams,load deflection curves,and steel bar strain curves of the core-filled assembled slab are obtained,which are in good agreement with the test.The slab simulation shows that cracks appear in the post-casting part and the prefabricated part,and the overall work performance is good.