GFRP for modified nano concrete flexual retrofitting of reinforced concrete beams

Figures & data

Figure 1. (a) scanning electron microscope image of NS of 50µ, (b) scanning electron microscope image of NS of 100µ.

Figure 2. (a) scanning electron microscope image of NC of 50µ, (b) scanning electron microscope image of NC of 100µ.

Table 1. As per IS: 10262 (2009): guidelines for concrete mix design for M₃₅ grade concrete

Water	Cement	Fine aggregate	Coarse aggregate
185.4	487.893	509.73	1218.17
0.38	1	1.04	2.5

Figure 3. a) and b) show the results of compressive strength of specimens. Cement replaced with Nano Clay and Nano Silica at a) 7th Day compressive strength. b) 28th Day compressive strength.

Figure 4. SEM images of concrete samples after 28 days of curing: (a,b,c,d). (a) conventional concrete, (b) concrete containing 4% NC and 0% NS.(c) concrete containing 2% NC and 4% NS and (d) concrete containing 0% NC and 4% NS.

Table 2. Compressive strength of concrete with cement replaced by nano clay and Nano silica

Specimen	Amount of replacement (%)		Crushing load N		Cumulative Compressive strength N/mm^2
	NC	NS	7 days	28 days	7 days	28 days
CS0–0	0	0	375	960	16.60	42.65
CS0–2		2	390	995	17.30	44.20
CS0–4		4	490	1255	21.75	46.00
CS0–6		6	460	1175	20.40	42.20
CS2–0	2	0	370	945	16.40	42.00
CS2–2		2	390	970	17.35	43.10
CS2–4		4	420	1075	18.65	47.75
CS2–6		6	410	1050	18.20	46.65
CS4–0	4	0	390	995	17.30	44.25
CS4–2		2	370	945	16.40	42.00
CS4–4		4	340	870	15.10	38.65
CS4–6		6	325	830	14.50	37.00
CS6–0	6	0	320	825	14.20	36.67
CS6–2		2	295	810	13.00	36.00
CS6–4		4	270	800	12.00	35.55
CS6–6		6	260	780	15.55	34.60

Table 3. Flexural strength of concrete beam with cement replaced by various percentage of NC and NS

specimen	Crushing load		Flexural strength
	Before retrofitting	After retrofitting	Before retrofitting	After retrofitting
CCC0–0	20	35	5.50	9.00
NCS0–4	22	37	6.00	10.10
NCS2–4	25	41	7.40	11.20
NCS2–6	30	44	8.00	12.20
NCS4–0	27	36	7.20	10.00
NCS4–2	22	33	5.90	9.10

Figure 5. Backscattered electron (BSE) images of polished surface of paste samples after 28 days of curing: (a) conventional concrete, (b) concrete containing 4% NC and 0% NS. (c) concrete containing 2% NC and 4% NS and (d) concrete containing 0% NC and 4% NS.

Figure 6. XRD analysis of different concrete samples after 28 days of curing: (c) concrete containing 2% NC and 4% NS and (d) concrete containing 0% NC and 4% NS.

IS: 10262. (2009). Indian standard concrete mix proportioning – guidelines.

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