Study on Mechanical Performance of ECC Reinforced by Polypropylene Fiber Mixed with Manufactured Sand and Carbon Black (CBMSPP-ECC) Based on Response Surface Method

Table 3

The level of experimental factors.

Symbol	Factors	Actual value (%)			Code value
A	PPF content	1.5	2%	2.5%	−1	0	1
B	FA content	40	60%	80%	−1	0	1
C	CB content	0.3	0.7%	1.1%	−1	0	1