
Plate 1: Length change test
Table 1: Mix proportions of concrete
|
Cement (kg) |
RHA (kg) |
Fine aggregate (kg) |
Coarse aggregate (kg) |
Water (kg) |
Water/ |
CTL |
399.12 |
0 |
798.24 |
1597.00 |
219.52 |
0.55 |
5% RHA |
379.16 |
19.96 |
798.24 |
1597.00 |
219.52 |
0.55 |
10% RHA |
359.21. |
39.91 |
798.24 |
1597.00 |
219.52 |
0.55 |
15% RHA |
339.25 |
59.87 |
798.24 |
1597.00 |
219.52 |
0.55 |
20% RHA |
319.30 |
79.82 |
798.24 |
1597.00 |
219.52 |
0.55 |
Plate 1: Length change test
Table 2: Oxide Composition of Rice Husk Ash (RHA)
S/N |
Elements |
Proportion (%) |
1 |
SiO2 |
87.23 |
2 |
Al2O3 |
0.35 |
3 |
Fe2O3 |
0.46 |
4 |
CaO |
0.10 |
5 |
MgO |
0.81 |
6 |
Na2O |
0.04 |
7 |
K2O |
2.97 |
8 |
SO3 |
0.36 |
9 |
MnO |
0.28 |
10 |
Pb2O5 |
2.62 |
11 |
TiO2 |
0.05 |
12 |
ZnO |
0.12 |
13 |
Cr2O3 |
0.03 |
14 |
BaO |
0.06 |
15 |
LOI |
3.18 |
Table 3: Physical Properties of Aggregate
Type of Test |
River Sand |
Natural moisture content (%) |
11.34 |
Bulk density (kg/m3) |
2233.05 |
Table 4: Particle size distribution for the constituent materials
Sieve size |
Coarse aggregates% Passing |
River sand |
RHA |
14.0mm |
100.00 |
|
|
12.0mm |
68.42 |
|
|
10 .0mm |
32.70 |
|
|
6.0 mm |
|
100.00 |
|
5.0 mm |
1.96 |
93.94 |
|
4.0 mm |
0.36 |
92.24 |
|
3.0 mm |
|
90.46 |
|
2.36 mm |
|
88.10 |
|
1.80 mm |
|
86.58 |
|
1.70 mm |
|
83.23 |
100.00 |
600 µm |
|
66.59 |
63.80 |
500 µm |
|
63.57 |
55.10 |
212 µm |
|
22.95 |
8.20 |
150 µm |
|
12.25 |
1.70 |
0.75 µm |
|
9.60 |
0.60 |
pan |
0.00 |
0.00 |
0.00 |
Figure 1: Setting time of the OPC/RHA binder
Table 5: Compacting factor, Slump test and Air Entrainment values
Percentage replacement (%) |
0 |
5 |
10 |
15 |
20 |
Compacting Factor mp / mf |
0.81 |
0.86 |
0.89 |
0.91 |
0.93 |
Slump values (cm) |
9.50 |
5.00 |
7.50 |
7.00 |
3.00 |
Air Entrainment (%) |
2.45 |
2.00 |
1.80 |
1.75 |
2.30 |
Figure 2: Compressive Strength Test Result for Concrete Immersed in Na2SO4 Moderate Solution (30,000 mg/L concentration)
Figure 3: Compressive Strength Test Result for Concrete Immersed in Na2SO4 Severe Solution ((50,000 mg/L concentration)
Figure 4: Compressive Strength Test Result for Concrete Immersed in MgSO4 Moderate Solution ((30,000 mg/L concentration)
Figure 5: Compressive Strength Test Result for Concrete Immersed in MgSO4 Severe Solution ((30,000 mg/L concentration)
Figures 6: Percentage of Compressive strength deterioration of concrete after 7 days immersion in sulfate
Figures 7: Percentage of Compressive strength deterioration of concrete after 28 days immersion in sulfate
Figures 8: Percentage of Compressive strength deterioration of concrete after 56 days immersion in sulfate
Figures 9: Percentage of Compressive strength deterioration of concrete after 90 days immersion in sulfate
Figure 10: Length change for Concrete Immersed in Na2SO4 and MgSO4 Moderate Solutions
Figure 11: Length change for Concrete Immersed in Na2SO4 and MgSO4 Severe Solutions
Figure 12: Percentage Water Absorption for Concrete Immersed in Na2SO4 and MgSO4 Moderate Solutions
Figure 13: Percentage Water Absorption for Concrete Immersed in Na2SO4 and MgSO4 Severe Solutions
Figure 14: Percentage Weight Loss for Concrete Immersed in Na2SO4 and MgSO4 Moderate Solutions
Figure 15: Percentage Weight Loss for Concrete Immersed in Na2SO4 and MgSO4 Severe Solutions
Figure 16: Penetration Depth for Concrete Immersed in Na2SO4 and MgSO4 Moderate and Severe Solutions
Table 6: ANOVA Result of the Compressive strength at 90 days
|
Sum of Squares |
df |
Mean Square |
F |
Sig. |
Between Groups |
1868.579 |
24 |
77.857 |
17.051 |
.000 |
Within Groups |
228.307 |
50 |
4.566 |
|
|
Total |
2096.886 |
74 |
|
|
|
Table 7: LSD test for Compressive strength of concrete samples at 90 days sulfate attack
i |
j |
MD(i-j) |
p |
Remark |
1 |
2 |
-10.43333* |
.000 |
* |
3 |
-14.63333* |
.000 |
* |
|
4 |
-12.60000* |
.000 |
* |
|
5 |
-12.50000* |
.000 |
* |
|
6 |
2.40000 |
.175 |
NS |
|
7 |
-6.46667* |
.001 |
* |
|
8 |
-10.60000* |
.000 |
* |
|
9 |
-7.66667* |
.000 |
* |
|
10 |
-6.90000* |
.000 |
* |
|
11 |
3.00000 |
.092 |
NS |
|
12 |
-6.53333* |
.000 |
* |
|
13 |
-11.50000* |
.000 |
* |
|
14 |
-7.86667* |
.000 |
* |
|
15 |
-7.10000* |
.000 |
* |
|
16 |
2.90000 |
.103 |
NS |
|
17 |
-6.50000* |
.000 |
* |
|
18 |
-10.20000* |
.000 |
* |
|
19 |
-8.10000* |
.000 |
* |
|
20 |
-7.96667* |
.000 |
* |
|
21 |
3.10000 |
.082 |
NS |
|
22 |
-5.93333* |
.001 |
* |
|
23 |
-9.63333* |
.000 |
* |
|
24 |
-7.63333* |
.000 |
* |
|
25 |
-7.60000* |
.000 |
* |
*Mean Difference is significant at p < 0.05, NS= Not Significant, 1-OPCCRL90, 2 -RHA5CRL90, 3 -RHA10CRL90, 4 -RHA15CRL90, 5 -RHA20CRL90, 6 -OPCNa2SO4M90, 7 -RHA5Na2SO4M90, 8-RHA10Na2SO4M90, 9 -RHA15Na2SO4M90, 10 -RHA20Na2SO4M90, 11 -OPCNa2SO4S90, 12 -RHA5Na2SO4S90, 13 -RHA10Na2SO4S90, 14 -RHA15Na2SO4S90, 15 -RHA20Na2SO4S90, 16 -OPCMgSO4M90, 17 -RHA5MgSO4M90, 18 -RHA10MgSO4M90, 19 -RHA15MgSO4M90, 20 -RHA20MgSO4M90, 21-OPCMgSO4S90, 22 -RHA5MgSO4S90, 23 -RHA10MgSO4S90, 24 -RHA15MgSO4S90, 25 -RHA20MgSO4S90
Tables at a glance
Figures at a glance