基于成熟度的二灰稳定碎石抗压强度预测方法

Prediction method of compressive strength of lime fly ash stabilized macadam based on maturity

为给沥青路面施工方案提供决策依据,在不同养护温度条件下、养护龄期分别为7、 14、 28、 42、 60、 90 d时,于实验室内测量4种二灰稳定碎石试件的抗压强度;结合活化能关系和度时积方程,分别构建基于成熟度的二灰稳定碎石抗压强度的3种预测模型;通过数据回归法和电子扫描显微镜结果对预测模型进行修正;将3种模型的预测值与实测值进行对比,验证预测模型的准确性。结果表明:二灰稳定碎石试件的抗压强度与龄期、温度均正相关,养护温度的影响大于养护龄期和二灰质量比的影响;活化能成熟度方程可以将不同温度下的实际养护龄期换算为标准温度下的等效龄期,该预测方便但预测结果误差较大。在恒定温度条件下,度时积成熟度方法在预测早期抗压强度时更接近实际值,但在龄期为14 d以后预测值较实际值略小。在变温度养护条件下,需要将近似基准温度设置为7℃,度时积成熟度方法预测二灰稳定碎石试件抗压强度不受二灰质量比、养护温度等因素干扰,具有更高的实用性。

In order to provide decision-making basis for the construction plan of asphalt pavement,under different curing temperature conditions and the curing ages were 7,14,28,42,60,90 d respectively,compressive strength of 4 kinds of lime fly ash stabilized macadam specimens were measured in the laboratory.Combining the activation energy relationship and the Nurse-Saul equation,3 prediction models of the compressive strength of lime fly ash stabilized macadam specimens based on maturity were constructed respectively.Based on the data regression method and the results of scanning electron microscope,the prediction model was revised.The predicted values of the 3 models were compared with the measured values to verify the accuracy of the predicted models.The results show that the compressive strength of the lime fly ash stabilized macadam specimen is positively correlated with age and temperature.The effect of curing temperature is greater than the effect of curing age or the mass proportions of lime fly ash.The activation energy maturity equation can convert the actual curing ages at different temperatures into the equivalent ages at the standard temperature.It is convenient to predict but the prediction result has a large error.Under constant temperature conditions,the Nurse-Saul equation maturity method is closer to the actual value when predicting the early compressive strength,but the predicted valuesare slightly smaller than the actual values after the age of 14 d.Under variable temperature curing conditions,the approximate reference temperature needs to be set to 7℃.The Nurse-Saul equation maturity method predicts the compressive strength of the lime fly ash stabilized macadam specimen without interference from the lime fly ash massproportions,curing temperaturesor other factors,which has higher practicability.