Research On The Basic Mechanical Properties Of Paving System On High-performance Lightweight Composite Bridge Deck

More and more attentions of scholars and engineers are being paid to the steel bridge deck pavement, which is an important part of the long-span bridge. However, there are many drawbacks and early failures for the traditional pavement on the steel bridge, for instance, rutting, cracking and extrusion. In order to solve these problems, the TPO (Thin Polymer Overlay) was introduced to form a high-performance lightweight composite deck paving system (STC+TPO for short) on the STC (Super Toughness Concrete)-Steel deck. In this paper, the basic mechanical properties of STC-TPO paving system were analyzed, the main research achievements are as follows:The stress characteristics and common diseases of steel bridge deck pavement were listed, then the primary causes of the deck pavement diseases were summarized as follows:the lack of steel deck rigidity and the physical or mechanical imperfection of the pavement materials. As an attempt to overcome the shortage of current deck pavement, the STC+TPO system were presented, and its controlling indexes were determined as tensile stress and interface shear stress.The performance parameters of STC, TPO and its interface were summarized after the study of their properties. The results indicated that STC and TPO were good enough to be applied on the steel deck and the reliable bonding of the interface could also be guaranteed. Subsequent mechanical calculations and reliability analysis were also on the basis of performance parameters acquired above.Based on the verified finite element model of Mafang Bridge, the stress and deformation of the STC+TPO paving system were studied. The calculation results indicated that STC+TPO could effectively reduce the stress or strain amplitude and local deformations in both pavement and steel deck. In addition, the stress status of the STC+TPO paving system were greatly influenced by the vehicle load, environment temperature and layer thickness. By considering the effects of multiple parameters, the stress in the pavement was calculated under the most unfavorable conditions.In this paper, the dynamic properties of the STC+TPO paving system were studied and the dynamic results were compared with the static results. Then some conclusions were made as follows:the maximum vertical displacement of pavement was almost the same in both the static calculation and dynamic calculation; the dynamic results of the maximum tensile stress in the pavement were influenced by the vehicle parameters and pavement structure, so it was different from the static results; because all the impact coefficients were less than0.2in the dynamic results, so it could be safe and reliable to set the impact coefficients as0.3in the static analysis.The results of reliability analysis for the STC+TPO paving system indicated that the STC and TPO layers could easily withstand tensile stress and shear stress under the conditions of heavy loads or extreme high temperature. So it could be concluded from the static analysis that STC+TPO was a high-performance pavement which could solve the problems of early damages in steel deck pavement.