An inverse approach to determine complex modulus gradient of field-aged asphalt mixtures

Table 2 Results of calculations of modulus gradient of a field core specimen (8 months aged at 30 °C) from direct tension test

Iteration	Loading time (s)	Pseudo strain (με)	Load (N)	a	b	c	n	k	n ₀	k ₀
1st	5–15	6.12	30.41	1.26	0.73	0.85	2.96	2.44	2.54	2.16
	16–25	20.42	165.6	1.28	0.72	0.86	3.73	2.82
	26–35	34.71	268.34	1.30	0.72	0.87	3.89	3.09
2nd	5–15	3.67	30.41	1.23	0.70	0.84	2.91	2.40	2.53	2.12
	16–25	12.15	165.6	1.26	0.71	0.85	3.68	2.79
	26–35	20.3	268.34	1.29	0.71	0.85	3.86	3.06
3rd	5–15	3.53	30.41	1.22	0.68	0.82	2.90	2.39	2.52	2.11
	16–25	11.79	165.6	1.25	0.70	0.84	3.67	2.76
	26–35	19.15	268.34	1.27	0.70	0.84	3.85	3.05