ABSTRACT

In a mechanistic-empirical (ME) pavement design method, the modulus of asphalt concrete (AC) is essential. The in-situ AC modulus can be obtained by the surface wave method (SWM). However, the measured modulus needs to be adjusted to the design frequency values. This study aimed to propose a frequency adjustment method for the in-situ AC seismic modulus. For this purpose, coring and dynamic modulus tests, FWD (Falling Weight Deflectometer) tests, and PSPA (Portable Seismic Pavement Analyzer) tests were carried out in the accelerated pavement test (APT). The master curves generated by the dynamic modulus results correlated well with the moduli determined from the other tests. Based on this relationship, a frequency adjustment factor was developed for the seismic modulus of the undamaged AC layer. For the damaged AC layer, the proposed factor was modified by incorporating the effect of the damage. Finally, to validate the frequency adjustment factor, the measured maximum tensile strains in the APT were compared with the values determined from the adjusted seismic moduli. The results prove that the frequency adjustment factor is appropriate to obtain the design modulus from the surface wave test. The PSPA test is also recommended to obtain the in-situ AC seismic modulus.

摘要

在机械经验 (ME) 路面设计方法中，沥青混凝土 (AC) 的模量至关重要。原位 AC 模量可以通过表面波法 (SWM) 获得。但是，测量的模量需要调整到设计频率值。本研究旨在提出一种现场交流地震模量的频率调整方法。为此，在加速路面试验 (APT) 中进行了取芯和动态模量试验、FWD（落锤挠度计）试验和 PSPA（便携式地震路面分析仪）试验。动态模量结果生成的主曲线与其他测试确定的模量很好地相关。基于此关系，为未损坏的 AC 层的地震模量开发了频率调整因子。对于受损的 AC 层，提议的因素已通过纳入损害的影响进行了修改。最后，为了验证频率调整因子，将 APT 中测得的最大拉伸应变与调整后的地震模量确定的值进行比较。结果证明，频率调整因子适用于从表面波试验中获得设计模量。还建议进行 PSPA 测试以获得原位 AC 地震模量。