沥青混凝土导温系数现场测定的峰值梯度法

建立路面温度场的一维瞬态热传导方程,通过分离变量法找到满足方程的傅立叶级数,获得在已知界面温度时一维层状体的瞬态温度分布.实测路面温度场数据,采用峰值梯度法反算路面材料导温系数.模拟路面降温过程中路面温度沿深度单调变化时,傅立叶级数解前50项就能够达到0.01℃的精度.对实测数据分析结果表明：峰值梯度法可以避免将不同温度传感器温度数值直接比较,结果较差分直接反算方法稳定.

Thermal Diffusivity Field Determination based on Fourier Series

Through establishment of one-dimensional transient heat conduction equation of pavement temperature field and the Fourier series obtained by separation of variables, the instantaneous temperature distribution of one dimensional layered body in terms of known interface temperature has been obtained. By means of temperature peak gradient method, to back-calculate the thermal diffusivity of pavement material based on measuring temper- ature distribution in field. In process of pavement cooling that temperature changes along the depth monotony, Fourier series with 50 items can attain the accuracy of 0.01 ℃. Results derived from measured data show that ： the temperature peak gradient method can avoid the direct comparison of temperature between different tempera- ture sensors; the results are more stable than those with difference back-calculation method.