Rheological Evaluation of Modified Bitumen by EVA and Crumb Rubber Using RSM Optimization

Table 6

Values of regression coefficients calculated for DSR tests.

Term	Temp (/sinδ ≥ 2.2 kPa)				Temp (/sinδ ≤ 5000 kPa)
	Coef	SE coef	T-value	value	Coef	SE coef	T-value	value
Constant	80.1672	0.3060	262.006	≤0.001	18.4828	1.063	17.390	≤0.001
EVA	2.9750	0.3008	9.889	≤0.001	5.3333	1.045	5.104	0.001
CR	1.3083	0.3008	4.349	0.003	1.8333	1.045	1.754	0.123
EVA  EVA	−1.0853	0.4434	−2.448	0.044	−0.6897	1.540	−0.448	0.668
CR  CR	−0.0853	0.4434	−0.192	0.853	1.8103	1.540	1.175	0.278
EVA  CR	−1.2125	0.3684	−3.291	0.013	−0.2500	1.280	−0.195	0.851