Effect of Bacillus cohnii on Some Physicomechanical and Microstructural Properties of Ordinary Portland Cement

Table 3

Results of comparison of compressive strength development of mortar with curing age.

Curing age (days)	Compressive strength (mean ± SE) MPa
	OPC-H2O-H2O	OPC-H2O-BC	OPC-BC-H2O	OPC-BC-BC
14	44.50 ± 1.40^a	45.00 ± 1.00^a	46.01 ± 1.15^a	47.00 ± 0.74^a
28	50.33 ± 0.66^b	53.06 ± 0.86^b	55.10 ± 0.48^b	56.81 ± 0.58^b
56	50.94 ± 0.28^b	55.04 ± 0.83^b	57.01 ± 0.07^b	58.61 ± 0.68^b
90	51.25 ± 0.65^b	61.63 ± 0.14^c	63.80 ± 1.04^c	65.75 ± 0.70^c
value	0.001	<0.001	<0.001	<0.001

Mean values followed by the same small letter within the same column do not differ significantly from one another (one-way ANOVA, α = 0.05, SNK-test).