Analysis On The Flexural Behavior Of ECC-concrete Composite Members

A series of problems,such as corrosion of steel bars and cracking of concrete,often occur in the process of the normal use of reinforced concrete structure,which leads to the whole structure less than the expected service life.The PVA-ECC material has a good ability to resist cracking and the infiltration of harmful substances such as chloride salts,which can significantly improve the safety and durability of the structure.The calculation formula of flexural bearing capacity and mid-span deflection of PVA-ECC reinforced concrete composite members are established in this paper.The load-displacement curve of PVA-ECC reinforced concrete composite members are drawn,which provides a theoretical basis for studying the flexural analysis of PVA-ECC reinforced concrete composite members.The main work and conclusions of this paper are as follows:(1)The formula of yield load and ultimate load of PVA-ECC reinforced concrete composite beams(single reinforcement section)are established.The influence of reinforcement corrosion is considered.Based on the assumption of the flat section of the specimen,the bilinear stress-strain relationship of the reinforcement and the stress-strain relationship of the concrete in the GB50010-2002 concrete structure design code,PVA-ECC can still bear certain tensile stress after cracking.The experimental data of this research group and other scholars at home and abroad are used to verify the results.The results show that the theoretical calculation of yield load and ultimate load agrees with the experimental values.And the error of the accurate calculation value of the ultimate load is smaller than that of the equivalent rectangular strain diagram.(2)The yield load and ultimate load calculation formula of PVA-ECC reinforced concrete composite slabs(double-bar section)are established.Based on the basic assumptions and considering the effect of reinforcing bars in the compression zone.The test of this research group is used for verification,and the results showed that: the average value of the ratio between the test value and the calculated value of the yield load is 0.9317.And the average value of the ratio between the test value and the calculated value of the ultimate load is 1.202,which indicates the reliability of the formula in this paper.The average error between the test value and the calculated value of the equivalent rectangular strain diagram is 36.97%.(3)The calculation formula of deformation capacity of PVA-ECC reinforced concrete composite member is established.The formula is verified by combining the test data in this paper with the relevant tests of other domestic scholars.And the loaddisplacement curves of each specimen are plotted.The theoretical calculation is in good agreement with the test data.