Analysis of the Behavior of Carbon Nanotubes on Cementitious Composites

Table 4

Tensile strength by diametric compression.

Age	Parameters	CN0	CN2	CN4	CN6	Average
3 days	Average 𝜎tr (MPa)	2,900	2,847	3,260	2,717	2,931
	Standard deviation	0,60655	0,18448	0,10583	0,14154
	Variance	0,36790	0,03403	0,01120	0,02003
	% gain/(reduction)	—	(1,80)	12,41	(6,20)
7 days	Average 𝜎tr (MPa)	2,893	3,057	3,693	2,987	3,158
	Standard deviation	0,30989	0,20984	0,40154	0,25146
	Variance	0,09603	0,4403	0,16123	0,06323
	% gain/(reduction)	—	5,65	27,68	3,46
28 days	Average 𝜎tr (MPa)	3,193	3,600	4,180	3,273	3,562
	Standard deviation	0,18903	0,13748	0,14000	0,27227
	Variance	0,03573	0,01890	0,01960	0,07413
	% gain/(reduction)	—	12,85	31,03	2,51
Average		2,966	3,168	3,711	2,992