水泥混凝土路面板早龄期徐变效应研究

EARLY-AGE CREEP EFFECTS OF CEMENT CONCRETE PAVEMENT

基于微预应力-固结理论徐变模型,综合考虑材料、结构以及环境参数影响,建立三维路面板早龄期力学行为仿真程序,开展了路面板三维结构徐变效应研究。研究显示,徐变对路面板早龄期作用是一种松弛效应,显著降低了路面板早龄期翘曲和应力;徐变对路面板早龄期行为的影响量级与温度梯度、板边约束的影响相当;徐变效应受板边约束、温湿度梯度和整体温度条件显著影响,空间位置存在不均匀分布特性,徐变作用下应力最大松弛位置向受约束的板边中部靠近;路面板徐变松弛效应有显著经时特性,前7天徐变效应最为显著,60天后趋于稳定;面板温度梯度与整体温度提高,徐变松弛效应显著增加。理论比较显示,忽略温度对徐变的影响会低估高温、高估低温条件下的徐变效应,工程中可基于徐变效应设计降低路面板早龄期初始翘曲与初始应力。

Based on a creep model for microprestress-solidification theory, considering the influence of material,structure and environmental parameters, a three-dimensional simulation program for early-age mechanical behavior of pavement was established, and the creep effects mechanism of three-dimensional pavement structure were analyzed. The results show that creep is a relaxation effect on early-age pavement, which significantly reduces the early-age curling and stress. The influence magnitude of creep on early-age behavior of pavement is similar to that of temperature gradient and that of edge constraint. Creep effect is also significantly affected by edge constraint, temperature gradient, humidity gradient and overall temperature conditions, and has spatial position non-uniform distribution characteristics. Under the effect of creep, the maximum relaxation position of stress is close to the middle of the restricted edge. The creep relaxation effect has significant time-dependent characteristics. It is most significant in the first 7 days and tends to be stable after 60 days. Creep relaxation effect increases significantly with temperature gradient and overall temperature increasing. Theoretical comparison shows that, ignoring the influence of temperature will underestimate the creep effect under high temperature and overestimate the creep effect under low temperature. It is recommended to use creep effect design to reduce earlyage curling and stress in pavement engineering.