Research On Interlayer Interface Performance Of Steel-ECO Composite Structure

The traditional steel bridge deck is often made of asphalt concrete pavement.Because asphalt materials are prone to the two classic diseases of bridge deck pavement damage and steel structure fatigue cracking,the emergence of high-toughness and high-durability concrete materials solves the above problems.The problem provides new ideas,among which ultra-high performance concrete（UHPC）and polyurethane concrete are the most representative.Due to the high cost and difficult construction of ultra-high performance concrete,it is difficult to be applied to steel bridge deck pavement on a large scale.In order to solve this problem,relevant domestic enterprises have developed a new type of modified polyurethane（referred to as ECO）concrete,which has the characteristics of high strength,good interlayer bonding performance,good low temperature crack resistance,etc.,and successfully applied to the deck pavement of many bridges.Although there are more and more applications of ECO concrete（ECOC）,at present,there are few studies on either ECOC itself or ECOC steel bridge deck pavement system,especially the material properties at different temperatures and the interface properties of Steel-ECO composite structures（SECS）.Relevant studies are rarely reported.For this reason,this paper uses a combination of experiments and numerical analysis to conduct in-depth research on the basic mechanical properties of ECOC and the interlayer interface properties of SECS.The main work and research results are as follows:（1）A total of 36 ECOC cubes,prisms and axial tensile specimens were designed and fabricated,and the basic mechanical property tests and constitutive relationship studies of ECOC were carried out.The tests of the specimens at-10°C,15°C,40°C,and 60°C were completed,the elastic modulus and Poisson’s ratio of ECOC under different temperature conditions were determined,and the uniaxial ECOC under different temperature conditions was constructed.The compressive and uniaxial tension constitutive model lays the foundation for the subsequent finite element analysis.（2）12 SECS specimens were designed and fabricated.The failure modes and shear performance of the SECS interface at four different temperatures were studied by oblique shear test.The results show that the failure mode of the specimens is the bond failure between the steel layer and the ECOC layer.The DIC image processing technology is used to solve the problem that the interface strain and slip are difficult to measure.Based on the analysis of the test data at four different temperatures,a limitless method for the interface of the SECS specimen under the action of 45°compression shear is proposed.Class bond-slip model.（3）According to the oblique shear test results of the SECS specimen,the functional relationship between the interface ultimate shear strength and temperature is established,and the expression isτ_max=14.7008+0.0132T-0.0017T².The interface ultimate shear strength of the SECS specimen is negatively correlated with temperature,and the interface ultimate shear strength decreases as the temperature increases;the overall stiffness of the SECS specimen is negatively correlated with temperature,and the temperature increases higher,the overall stiffness of the specimen decreases.（4）Based on the above-established ECO uniaxial tension and uniaxial compression constitutive relationships and the proposed interface bond-slip constitutive relationship,the ABAQUS software was used to establish a SECS finite element model.The SECS under the condition is subjected to finite element analysis and compared with the test results.The results show that it is feasible and effective to carry out the finite element analysis of the SECS by using the double-line cohesion model.Under the conditions of-10°C,15°C,40°C,and 60°C,the relative error between the calculated load peak value of the interface oblique shear finite element and the experimental value is within 6%;the relative error between the finite element calculation value and the experimental value of the maximum shear stress at the interface is 5%or less.