Study On Quality Inspection Technology Of Composite Floor Slab Of Precast Concrete Structure

Composite floor slab for its construction speed,energy saving and environmental protection,reduce wet operation and other advantages,in recent years the application of precast concrete structure in a wide range of.The composite floor slab is composed of precast slab and post-poured concrete,in which the precast slab is manufactured in the factory and transported to the construction site for assembling and pouring post-poured concrete after meeting the strength requirements.Because the precast slab is manufactured in the factory,it has product attributes,and composite floor slab is a secondary forming component,which is liable to produce quality problems at the joint during post-pouring,which brings hidden dangers to the application of composite floor slab in engineering,and the corresponding testing technical standards are not perfect at present.In order to ensure that the quality of composite floor slab fulfils the design requirements,this paper carries out experimental research on the influence of structural performance test of precast slab,joint defect detection and joint defect on the mechanical performance of composite floor slab,and puts forward corresponding inspection methods and matters needing attention.The specific work is as follows:(1)There is no corresponding test specification and standard atlas for the performance test of the precast slab of steel bar truss at present,it is proposed that the test load is determined by the bearing capacity of the floor and the truss reinforcement,and the static load test of two precast slabs of steel bar truss is carried out to verify the results,the error between experimental results and theoretical formulas is small,the calculation method is reasonable and can be used,the test load is determined by the structural performance test of precast slab.At the same time,in view of another kind of large-span prestressing hollow floor slab commonly used at present,the field inspection research is also carried out,because this type of composite slab develops earlier,the corresponding standard atlas has been made for the structural performance inspection at present,the test only tests the limit state of the normal use of large-span prestressing hollow floor slab,and points out through the test that this type of composite slab structure has been developed earlier,notices in performance testing.(2)Combining with the defects of composite floor slab joint in practical engineering,four composite floor slabs with different defects are designed and manufactured,the defects of composite floor slab joint are detected by array ultrasonic imaging method and impact-echo method with one-sided detection function,the test results show that array ultrasonic imaging method can locate the defects of composite floor slab joint and display them by imaging,its location depth and accuracy are high;impact-echo method can only locate part of the defects,which has high detection efficiency,further research is needed on its applicability to joint defect detection.(3)Taking the joint defect as the research object,five composite floor slabs with different defect sizes and different defect locations were tested to study the effect of the defect on the mechanical properties of the composite floor slabs,the test results show that the joint defect at the maximum bending moment is more obvious with the increase of the defect;the joint defect at different locations of the same size is the biggest bending moment,defects in location have the greatest impact on the composite floor slab;cracks first appear under the floor where there are defects in the joint surface during the loading process.