1 Introduction
2 Experimental Details
2.1 Concrete Mixtures
Mixtures | Ambient curing temperature (°C) |
w/cm (%) | Quantity (kg/m3) | ||||||
---|---|---|---|---|---|---|---|---|---|
Water | Modified cement | SF | GGBFS | Sand | Gravel |
R
sp
* (%) | |||
S5 | 5 | 34 | 155 | 433 | 23 | – | 737 | 941 | 1.5 |
G50 | 20 | 34 | 155 | 228 | – | 228 | 705 | 900 | 0.7 |
G65S5 | 35 | 34 | 155 | 137 | 23 | 296 | 703 | 897 | 0.5 |
2.2 Materials
Materials | SiO2
| Al2O3
| Fe2O3
| CaO | MgO | K2O | Na2O | TiO2
| SO3
| LOI* |
---|---|---|---|---|---|---|---|---|---|---|
Modified cement | 23.30 | 3.85 | 3.83 | 63.4 | 1.24 | 1.47 | 0.15 | 0.33 | 2.01 | 0.42 |
SF | 98.94 | 0.30 | 0.08 | 0.12 | 0.04 | 0.13 | 0.05 | – | 0.28 | 0.06 |
GGBFS | 33.18 | 14.07 | 0.51 | 44.6 | 4.31 | 0.45 | 0.24 | 0.55 | 1.36 | 0.73 |
Type | Maximum size (mm) | Bulk density (kg/m3) | Specific gravity | Water absorption (%) | Fineness modulus |
---|---|---|---|---|---|
Coarse aggregates | 25 | 1.557 | 2.59 | 0.78 | 6.64 |
Fine aggregates | 5 | 1.668 | 2.56 | 1.34 | 2.80 |
2.3 Mock-up Wall Specimens and Curing
2.4 Testing
3 Test Results and Discussion
3.1 Temperature Rise
3.2 Activation Energy Until Final Setting Time
Mixtures | Setting time (hrs) |
E
s
(J/mol) |
E
i
(J/mol) |
k
t
(1/days) | |||||||
---|---|---|---|---|---|---|---|---|---|---|---|
5 °C | 20 °C | 35 °C | |||||||||
Initial | Final | Initial | Final | Initial | Final | 5 °C | 20 °C | 35 °C | |||
S5 | 16.30 | 23.00 | 10.80 | 14.92 | 6.50 | 7.70 | 22,700 | 42,200 | 0.16 | 0.30 | 0.95 |
G50 | 17.34 | 28.30 | 12.34 | 18.37 | 7.42 | 8.57 | 24,800 | 54,700 | 0.07 | 0.18 | 0.72 |
G65S5 | 21.80 | 31.20 | 15.20 | 20.30 | 8.00 | 8.90 | 26,100 | 68,900 | 0.05 | 0.15 | 0.70 |
3.3 Initial Activation Energy at Start of Hardening Phase
3.4 28-Day Compressive Strength (S 28 )
3.5 Comparison of Compressive Strength Development
Mixture | Specimens | Compressive strength (MPa) at different ages (days) | ||||||
---|---|---|---|---|---|---|---|---|
3 | 7 | 14 | 28 | 56 | 91 | |||
S5 | Field-cured cylinder | 21.5 | 37.9 | 50.9 | 58.9 | 67.5 | 75.8 | |
Core (location drilled from walls) | Top surface | 32.4 | 49.2 | 61.9 | 65.3 | 65.5 | 66.7 | |
Top center | 34.4 | 48.5 | 62.8 | 66.0 | 66.6 | 67.0 | ||
Middle surface | 36.6 | 51.4 | 64.7 | 68.3 | 68.3 | 69.7 | ||
Middle center | 44.9 | 52.3 | 61.4 | 67.8 | 69.8 | 71.0 | ||
G50 | Field-cured cylinder | 18.4 | 37.5 | 45.5 | 53.4 | 55.4 | 58.9 | |
Core (location drilled from walls) | Top surface | 27.8 | 44.2 | 50.2 | 62.6 | 63.4 | 65.4 | |
Top center | 35.9 | 50.0 | 56.0 | 63.5 | 64.6 | 65.7 | ||
Middle surface | 29.4 | 43.7 | 56.4 | 65.5 | 65.5 | 67.1 | ||
Middle center | 33.6 | 53.0 | 56.2 | 66.0 | 67.0 | 67.6 | ||
G65S5 | Field-cured cylinder | 30.7 | 45.3 | 52.2 | 55.4 | 55.1 | 58.3 | |
Core (location drilled from walls) | Top surface | 32.7 | 48.4 | 54.5 | 56.2 | 56.8 | 58.3 | |
Top center | 43.3 | 54.9 | 57.0 | 60.6 | 58.3 | 60.6 | ||
Middle surface | 35.8 | 48.3 | 55.8 | 59.7 | 61.3 | 62.8 | ||
Middle center | 41.3 | 55.6 | 56.0 | 60.4 | 63.3 | 63.7 |
4 Comparisons of Maturity Functions and Experiments
4.1 Review of Existing Models
Researcher | Formulation of the relationship |
---|---|
Kim et al. (2002a) |
\( \frac{S}{{S_{u} }} = \left\{ {1 - \frac{1}{{\sqrt {1 + \sum\limits_{i = 1}^{n} {A\left[ {e^{{ - \frac{{E_{a} (i)}}{{R\left[ {T_{c} (i) + 273} \right]}}e^{{ - \alpha t_{i} }} }} +\, e^{{ - \frac{{E_{a} (i)}}{{R\left[ {T_{c} (i) + 273} \right]}}e^{{ - \alpha t_{i - 1} }} }} } \right](t_{i} - t_{i - 1} } )} }}} \right\} \)
where \( A = 1 \times 10^{7} \) (experimental constant); \( E_{a} (i) = 42830 - 43T_{c} (i) \) (in J/mol);
\( \alpha = 0.00017T_{c} (i) \); and \( t_{o} = 0.66 - 0.011T_{c} (i) \ge 0 \)
|
Pinto and Schindler (2010) |
\( \frac{S}{{S_{u} }} = \frac{{k_{r} (t_{e}^{*} - t_{sr} )}}{{1 + k_{r} (t_{e}^{*} - t_{sr} )}} \)
where \( t_{sr} = t_{s} \exp \left[ { - \frac{{E_{s} }}{R}\left( {\frac{1}{{T_{c} (i) + 273}} - \frac{1}{{T_{r} + 273}}} \right)} \right] \); and
\( t_{e}^{*} = \sum\limits_{0}^{{t_{sr} }} {\exp \left[ { - \frac{{E_{s} }}{R}\left( {\frac{1}{{T_{c} (i) + 273}} - \frac{1}{{T_{r} + 273}}} \right)} \right]} \Updelta t_{i} + \sum\limits_{0}^{t} {\exp \left[ { - \frac{{E_{i} }}{R}\left( {\frac{1}{{T_{c} (i) + 273}} - \frac{1}{{T_{r} + 273}}} \right)} \right]} \Updelta t_{i} \)
|
Yang (2014) |
\( \frac{S}{{S_{28} }} = \beta_{1} \frac{{k_{r} (t_{e} - t_{or} )}}{{1 + k_{r} (t_{e} - t_{or} )}} \)
where \( \beta_{1} = \frac{{S_{u} }}{{S_{28} }} = 1 + \frac{1}{{k_{r} \cdot 28}} \); \( k_{T} = k_{r} \exp \left[ { - \frac{{E_{a} (i)}}{R}\left( {\frac{1}{{T_{c} (i) + 273}} - \frac{1}{{T_{r} + 273}}} \right)} \right] \);
\( t_{or} = t_{sr} \exp \left[ { - \frac{{E_{s} }}{R}\left( {\frac{1}{{T_{c} (i) + 273}} - \frac{1}{{T_{r} + 273}}} \right)} \right] \);
\( t_{e} = \sum\limits_{0}^{{t_{sr} }} {\exp \left[ { - \frac{{E_{s} }}{R}\left( {\frac{1}{{T_{c} (i) + 273}} - \frac{1}{{T_{r} + 273}}} \right)} \right]} \Updelta t_{i} \)
\( + \sum\limits_{{t_{sr} }}^{3} {\exp \left[ { - \frac{{E_{a} (i)}}{R}\left( {\frac{1}{{T_{c} (i) + 273}} - \frac{1}{{T_{r} + 273}}} \right)} \right]} \Updelta t_{i} + \sum\limits_{3}^{t} {\exp \left[ { - \frac{{E_{a} (i)}}{R}\left( {\frac{1}{{T_{A3} + 273}} - \frac{1}{{T_{r} + 273}}} \right)} \right]} \Updelta t_{i} \)
\( S_{28} = \left[ {\left( {\frac{{T_{A3} }}{{T_{r} }}} \right)^{2} (w/cm)^{4} + 0.97} \right](S_{28} )_{{T_{r} }} \); and
\( E_{a} (i) = E_{i} \cdot \exp ( - 0.00017T_{c} (i) \cdot t) \)
|
4.2 Comparisons with Test Results
Mixtures | Statistics | Kim et al. (2002a) | Pinto and Schindler (2010) | Yang (2014) | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Age (days) | Total | Age (days) | Total | Age (days) | Total | |||||||||||
3 | 7 | 28 | 91 | 3 | 7 | 28 | 91 | 3 | 7 | 28 | 91 | |||||
S5 | ||||||||||||||||
γ
m
| 1.084 | 0.866 | 0.757 | 0.825 | 0.883 | 0.942 | 0.888 | 0.843 | 0.890 | 0.890 | 1.130 | 1.101 | 1.044 | 1.022 | 1.074 | |
γ
s
| 0.312 | 0.188 | 0.057 | 0.060 | 0.213 | 0.273 | 0.144 | 0.028 | 0.062 | 0.150 | 0.217 | 0.177 | 0.066 | 0.080 | 0.144 | |
γ
v
| 0.288 | 0.218 | 0.076 | 0.073 | 0.241 | 0.290 | 0.162 | 0.033 | 0.070 | 0.168 | 0.192 | 0.161 | 0.061 | 0.078 | 0.134 | |
G50 | ||||||||||||||||
γ
m
| 1.475 | 1.098 | 0.992 | 1.072 | 1.159 | 0.980 | 0.969 | 0.974 | 1.040 | 0.991 | 1.063 | 1.021 | 0.965 | 0.986 | 1.009 | |
γ
s
| 0.103 | 0.042 | 0.066 | 0.043 | 0.201 | 0.035 | 0.030 | 0.060 | 0.040 | 0.049 | 0.072 | 0.079 | 0.037 | 0.024 | 0.065 | |
γ
v
| 0.069 | 0.038 | 0.067 | 0.040 | 0.173 | 0.036 | 0.031 | 0.062 | 0.0390 | 0.049 | 0.067 | 0.077 | 0.039 | 0.024 | 0.064 | |
G65S5 | ||||||||||||||||
γ
m
| 1.393 | 1.151 | 1.147 | 1.170 | 1.215 | 0.855 | 1.010 | 1.110 | 1.141 | 1.029 | 1.215 | 1.086 | 1.053 | 1.076 | 1.107 | |
γ
s
| 0.122 | 0.062 | 0.037 | 0.040 | 0.125 | 0.080 | 0.046 | 0.034 | 0.039 | 0.124 | 0.109 | 0.046 | 0.029 | 0.040 | 0.087 | |
γ
v
| 0.087 | 0.054 | 0.032 | 0.034 | 0.103 | 0.094 | 0.045 | 0.030 | 0.034 | 0.120 | 0.090 | 0.042 | 0.028 | 0.037 | 0.079 |