Efficacy of Natural Zeolite and Metakaolin as Partial Alternatives to Cement in Fresh and Hardened High Strength Concrete
Table 3
Linear regression for the strength of concrete for all mix designs for 3, 7, 28, 60, and 90 days for 5% of natural zeolite with varying percentages of metakaolin.
Test
Model
β0 (constant)
β1 (days)
β2 (combination)
R-squared (%)
F-statistic
P value
Compression test
SFD
31.33 [12.78]
7.17 [9.71]
NA
84
94.22
<0.05
SFC
46.91 [7.56]
NA
2.37[1.05]
6
1.10
0.309
DFDC
6.394[9.10]
0.893[11.78]
0.433[3.08]
90
74.10
<0.05
Split tensile test
SFD
2.855[22.95]
0.416[11.10]
NA
87
123.25
<0.05
SFC
3.8[10.68]
NA
0.125[0.96]
5
0.93
0.348
DFDC
2.543[18.32]
0.416[13.75]
0.125[3.26]
92
99.82
<0.05
Flexural test
SFD
3.609[19.15]
1.044[18.38]
NA
95
337.75
<0.05
SFC
6.273[7.24]
NA
0.188[0.59]
2
0.35
0.561
DFDC
3.14[14.87]
1.044[22.65]
0.188[3.22]
97
261.80
<0.05
SFD is the single-factor curing days, SFC is the single-factor concrete mix combination, DFDC is the double factor both curing days and concrete mix combination, indicates significant at 0.05 level, and the parenthesis denotes t statistics (t-value).
