Theoretical analysis of stress of asphalt mixture bridge deck pavement based on design index

Abstract

At present, the specification for the design of asphalt mixture bridge deck pavement is missing, so it is of great significance to research on it. In order to study the design theory of asphalt mixture bridge deck pavement, the bottom tensile strain of asphalt mixture layer and the permanent deformation of asphalt mixture layer as the design index of asphalt mixture bridge deck pavement have been selected. Combined with a specific simply supported slab bridge, the mechanical properties and influencing factors of asphalt mixture bridge deck pavement based on the design index have been analyzed. Firstly, the section characteristic calculation basis of fatigue checking calculation is proposed by using the standard method, and the fatigue section characteristic of simply supported solid slab bridge is analyzed. Considering different load positions, the calculation method of fatigue stress under design load and ultimate load is proposed, and the fatigue stress is calculated. According to the equal strain principle, the bottom stress of asphalt mixture is calculated. Secondly, based on the assumption of plane section, the strain calculation formula of rectangular section with two parameters under temperature load is deduced. Using the derivation formula, the stress distribution of the section under the action of uniform temperature and gradient temperature is calculated, and the general stress distribution law is obtained. Finally,take Specification for design of highway asphalt pavement (JTG D50-2017) for reference to calculate the permanent deformation of asphalt mixture bridge deck pavement; Compared with the field measured value, the theoretical calculated value is less than the field measured value, which may be related to the insufficient compaction of asphalt on the bridge deck.