Improving the Interfacial Bond Properties of the Carbon Fiber Coated with a Nano-SiO₂ Particle in a Cement Paste Matrix

Table 5

Obtained results from the pull-out test.

Type of specimens	Replacement ratio of SF (wt.%)	No. of specimens	Maximum load (N)	Displacement at max. load (mm)	Frictional bond strength (sd)
					τmax (MPa)	Ratio (B/A, %)
PCFSF0-3 d (A)	—	1	283	2.48	3.15	122.3
		2	380	2.60	4.23
		3	387	3.05	4.31
		Average	350	2.71	3.90 (0.65)
CCFSF0-3 d (B)		1	486	3.15	5.41
		2	475	2.67	5.29
		3	324	2.35	3.61
		Average	428	2.72	4.77 (1.01)
PCFSF0-7 d (A)		1	361	2.76	4.02	126.6
		2	372	1.89	4.14
		3	362	1.90	4.03
		Average	365	2.18	4.06 (0.07)
CCFSF0-7 d (B)	—	1	424	2.54	4.72
		2	487	2.61	5.29
		3	475	2.67	5.42
		Average	462	2.60	5.14 (0.37)
PCFSF0-28 d (A)		1	325	2.52	3.62	127.3
		2	471	2.56	5.24
		3	394	2.55	4.39
		Average	397	2.54	4.42 (0.81)
CCFSF0-28 d (B)		1	484	2.68	5.39
		2	514	3.13	5.72
		3	520	2.29	5.79
		Average	506	2.70	5.63 (0.21)
PCFSF10-3 d (A)	10	1	414	1.80	4.61	122.1
		2	355	2.32	3.95
		3	387	3.05	4.31
		Average	385	2.39	4.29 (0.33)
CCFSF10-3 d (B)		1	501	3.15	5.58
		2	450	3.44	5.01
		3	461	3.23	5.13
		Average	471	3.27	5.24 (0.30)
PCFSF10-7 d (A)		1	412	2.08	4.59	123.0
		2	352	2.98	3.92
		3	416	3.28	4.63
		Average	393	2.78	4.38 (0.40)
CCFSF10-7 d (B)	10	1	481	2.54	5.36
		2	509	3.30	5.67
		3	463	2.87	5.15
		Average	484	2.90	5.39 (0.26)
PCFSF10-28 d (A)		1	421	2.53	4.69	133.0
		2	354	2.32	3.94
		3	401	2.50	4.46
		Average	392	2.45	4.36 (0.38)
CCFSF10-28 d (B)		1	579	2.87	6.45
		2	529	2.82	5.89
		3	456	2.93	5.08
		Average	521	2.87	5.80 (0.69)

sd is the standard deviation; B/A is the increase ratio of frictional bond strength.