Cement–paperboard composite for speaker/woofer casing: Experimental trend analysis (ETA) and performance evaluation

Figures & data

Figure 1. Image of (a) banana plant (b) banana fiber used in the study

Figure 2. (a) Snail shell powder; (b) waste packaging paper pulp; (c) untrimmed paperboard

Table 1. Mix proportion in composites samples

Banana fiber	Snail shell powder	Cement	Paper pulp
0	15	15	70.0
0.5	15	15	69.5
1.0	15	15	69.0
1.5	15	15	68.5
2.0	15	15	68.0
2.5	15	15	67.5

Table 2. Properties of Cement

Properties	Specific gravity	Specific surface area	Initial setting time	Final setting time	Soundness
Value	3.21	2643 m^2/kg	34 min	540 min	4.6 mm

Table 3. Chemical composition of snail shell powder additive

Compound	SiO2	Al2O3	CaO	Fe2O3	Na2O	MnO	TiO2	MgO	Na2O	SO3	Others	LOI
Amount	14.98	2.4	61.37	4.21	0.59	0.72	0.39	2.08	1.14	1.43	5.21	6.48

Table 4. Chemical composition of treated and untreated banana fiber

Constituents	Untreated BF Fiber	Treated BF Fiber
Cellulose (%)	61.40	72.61
Hemicellulose (%)	22.11	16.42
Lignin (%)	6.28	3.81
Ash (%)	2.40	1.76
Moisture	5.80	3.60
Others (%)	2.01	1.80

Figure 3. Surface morphology of (a) untreated and (b) 1 M NaOH treated banana fiber

Figure 4. Surface morphology and EDX analysis of snail shell powder

Figure 5. Variation in water absorption at curing days of (a) 28 days and (b) 56 days with (c) experimental trend index (d) efficiency values of the experimental variables

Figure 6. Variation in thickness swelling at curing days of (a) 28 days and (b) 56 days with (c) experimental trend index (d) efficiency values of the experimental variables

Figure 7. Variation in surface screw holding strength at curing days of (a) 28 days and (b) 56 days with (c) experimental trend index (d) efficiency values of the experimental variables

Figure 8. Variation in modulus of rupture at curing days of (a) 28 days and (b) 56 days with (c) experimental trend index (d) efficiency values of the experimental variables

Figure 9. Variation in modulus of elasticity at curing days of (a) 28 days and (b) 56 days with (c) experimental trend index (d) efficiency values of the experimental variables

Table 5. Experimental variable efficiency table

Properties	Experimental Variables
	Untreated Banana Fiber (%)	Treated Banana Fiber (%)	Alkaline treatment (%)	Curing duration (%)
Water absorption	10.2 [-]	−7.4 [-]	2.8 [+]	18.4 [+]
Thickness swelling	17.0 [-]	−8.6 [-]	8.4 [+]	20.1 [+]
Internal bond strength	14.7 [+]	21.8 [+]	7.1 [+]	32.5[+]
Screw holding strength	26.2 [+]	34.7 [+]	8.5 [+]	26.4 [+]
Modulus of rupture	22.6 [+]	32.9 [+]	10.3 [+]	29.3 [+]
Modulus of elasticity	10.7 [+]	16.8 [+]	6.1 [+]	7.9 [+]

Figure 10. Resultant efficiencies of experimental variables

Table 6. Response index for composites in comparison with standard values

Fiber proportion	Water absorption				Thickness swelling
	UBF-28	TBF-28	UBF-56	TBF-56	UBF-28	TBF-28	UBF-56	TBF-56
0	1	1	1	1	1	1	1	1
0.5	1	1	1	1	1	1	1	1
1	1	1	1	1	1	1	1	1
1.5	1	1	1	1	1	1	1	1
2	1	1	1	1	1	1	1	1
2.5	1	1	1	1	1	1	1	1
Fiber proportion	Internal bond strength				Screw holding strength
	UBF-28	TBF-28	UBF-56	TBF-56	UBF-28	TBF-28	UBF-56	TBF-56
0	1	1	1	1	0	0	0	0
0.5	1	1	1	1	0	0	0	0
1	1	1	1	1	0	0	1	1
1.5	1	1	1	1	0	0	1	1
2	1	1	1	1	0	0	1	1
2.5	1	1	1	1	0	0	1	1
Fiber proportion	Modulus of rupture (MOR)				Modulus of elasticity (MOE)
	UBF-28	TBF-28	UBF-56	TBF-56	UBF-28	TBF-28	UBF-56	TBF-56
0	0	0	0	0	0	0	0	0
0.5	0	0	0	1	0	0	0	0
1	0	0	0	1	0	0	0	0
1.5	0	0	1	1	0	1	0	0
2	0	1	1	1	1	1	0	0
2.5	0	1	1	1	1	1	0	0

Table 7. Compliance index of composites reinforced with fiber proportion (0–2.5%)

Fiber proportion	UBF-28	TBF-28	UBF-56	TBF-56
0	0.50	0.50	0.50	0.50
0.5	0.50	0.50	0.50	0.67
1.0	0.50	0.50	0.67	0.83
1.5	0.50	0.67	0.83	0.83
2.0	0.67	0.83	0.83	0.83
2.5	0.67	0.83	0.83	0.83

Table 8. Effective Property Index (EPI) of developed composite reinforced with 0–2.5 wt.% UBF and TBF

Fiber proportion	UBF-28	TBF-28	UBF-56	TBF-56
0	0.59	0.59	0.68	0.68
0.5	0.50	0.58	0.58	0.65
1.0	0.65	0.72	0.76	0.84
1.5	0.65	0.75	0.79	0.85
2.0	0.67	0.77	0.80	0.87
2.5	0.69	0.77	0.82	0.90

Figure 11. Measurement of alkaline treatment and curing potential through (a) mean property index (b) efficiency of alkaline treatment and hydration

Figure 12. Microstructural image of composites (cured for 56 days) and containing (a) 1 wt.% TBF (EPI of 0.84, (b) 1.5 wt.% TBF (EPI of 0.85), (c) 2 wt % TBF (EPI of 0.87), and (d) 2.5 wt.% TBF (EPI of 0.9) cured for 56 days and possessed

Figure 13. High magnification fluorescence (HMF) microstructural sketch images of composites (cured for 56 days) and containing 2.5 wt.% TBF (EPI of 0.9) cured for 56 days