Effect of Hybrid Steel-Basalt Fiber on Behaviors of Manufactured Sand RPC and Fiber Content Optimization Using Center Composite Design

Table 10

Code levels.

Symbol	Factors	Actual values					Code values
A	Steel fiber content (%)	1	1.44	2.5	3.56	4	−α	−1	0	+1	α
B	Basalt fiber content (%)	0	0.05	0.175	0.3	0.35	−α	−1	0	+1	α