Optimization of Concrete Containing Polyethylene Terephthalate Powder and Rice Husk Ash Using Response Surface Methodology

Table 4

Results of ANOVA.

Source	DF	Slump (mm)			Compressive strength (N/mm^2)			Flexural strength (N/mm^2)
		SS	F value	value	SS	F value	value	SS	F value	value
Model	5	190.778	16.88852	0.020914	76.02778	20.78734	0.015553	1.640978	12.15873	0.033172
A	1	88.166	39.02459	0.008275	6	8.202532	0.064365	0.212817	7.884262	0.06741
B	1	48.167	21.31967	0.019117	60.16667	82.25316	0.002832	1.3824	51.21405	0.005619
AB	1	25	11.06557	0.044836	6.25	8.544304	0.061344	0.0196	0.726125	0.456764
A ^2	1	9.388	4.155738	0.134232	3.555556	4.860759	0.114666	0.023472	0.86958	0.41986
B ^2	1	20.055	8.877049	0.058623	0.055556	0.075949	0.800756	0.002689	0.099616	0.772974
Residual	3	6.77778			2.194444			0.080978

A-RHA; B-PET; SS: sum of squares; DF: degrees of freedom.