1 Introduction
2 Material and Methods
2.1 Materials and Mix Proportions
Specific surface area /(m2/kg) | Soundness/mm | Setting time /min | Flexural strength /MPa | Compressive strength /MPa | |||
---|---|---|---|---|---|---|---|
Initial setting time | Final setting time | 3d | 28d | 3d | 28d | ||
350 | 1.0 | 190 | 242 | 6.6 | 9.1 | 29.0 | 57.6 |
Fiber type | Diameter/mm | Length/mm | Aspect ratio | Tensile strength/MPa | E/GPa | Elongation/% | Density/g·cm−3 | Alkali resistance /% | Recommended content/kg m−3 |
---|---|---|---|---|---|---|---|---|---|
FF1 | 0.026 | 19 | 730.77 | 641 | 4.5 | 40 | 0.91 | 99.8 | 0.9 |
FF2 | 0.1 | 19 | 190 | 472 | 5.8 | 19.9 | 0.91 | 99.8 | 0.9 |
CF | 0.8 | 50 | 62.5 | 706 | 7.4 | 10.0 | 0.95 | 99.7 | 6.0 |
Specimen no. | Fiber type | Cement | Sand | Coarse aggregate | Water | Fiber content | Water reducer /% | |
---|---|---|---|---|---|---|---|---|
5 ~ 10 mm | 10 ~ 20 mm | |||||||
A0 | NO | 456 | 787 | 505 | 505 | 164 | 0 | 1 |
A1 | FF1 | 456 | 787 | 505 | 505 | 164 | 0.9 | 1 |
A2 | FF2 | 456 | 787 | 505 | 505 | 164 | 0.9 | 1 |
A3 | CF | 456 | 787 | 505 | 505 | 164 | 6.0 | 1 |
A4 | FF1 + CF | 456 | 787 | 505 | 505 | 164 | 0.6 + 5.4 | 1 |
A5 | FF1 + CF | 456 | 787 | 505 | 505 | 164 | 0.9 + 5.1 | 1 |
A6 | FF1 + CF | 456 | 787 | 505 | 505 | 164 | 1.2 + 4.8 | 1 |
A7 | FF1 + FF2 + CF | 456 | 787 | 505 | 505 | 164 | 0.45 + 0.45 + 5.1 | 1 |
A8 | FF1 + FF2 + CF | 456 | 787 | 505 | 505 | 164 | 0.6 + 0.6 + 4.8 | 1 |
2.2 Specimen Preparation
Specimen no. | A0 | A1 | A2 | A3 | A4 | A5 | A6 | A7 | A8 |
---|---|---|---|---|---|---|---|---|---|
Vebe consistency time/s | 23 | 24 | 26 | 28 | 27 | 27 | 25 | 27 | 25 |
2.3 Mechanical Tests
3 Results and Discussion
3.1 Compressive Strength
3.2 Splitting Tensile Strength
3.3 Uniaxial Tensile Performance
3.3.1 Failure Process
3.3.2 Load–Displacement Curve
3.3.3 Strength and Toughness
Specimen no. | \(f_{t}\)/MPa | \(\varepsilon_{t}\)/\({{\mu \varepsilon }}\) | \(W_{0.2}\)/N·m | \(R_{e,0.2}\) |
---|---|---|---|---|
A0 | 3.62 | 151.62 | 0.76 | 0.059 |
A1 | 3.75 | 176.28 | 0.92 | 0.068 |
A2 | 3.98 | 170.06 | 1.12 | 0.078 |
A3 | 4.39 | 181.43 | 5.28 | 0.334 |
A4 | 4.13 | 229.17 | 4.90 | 0.330 |
A5 | 4.02 | 253.04 | 4.02 | 0.278 |
A6 | 3.90 | 276.91 | 4.17 | 0.297 |
A7 | 4.64 | 224.93 | 6.32 | 0.378 |
A8 | 4.53 | 239.43 | 6.59 | 0.404 |
3.3.4 Constitutive Models
Specimen no. | A0 | A1 | A2 | A3 | A4 | A5 | A6 | A7 | A8 |
---|---|---|---|---|---|---|---|---|---|
\(E_{c}\)/GPa | 43.7 | 44.5 | 45.6 | 45.0 | 43.6 | 45.1 | 43.1 | 44.5 | 42.1 |
Specimen no. | A0 | A1 | A2 | A3 | A4 | A5 | A6 | A7 | A8 |
---|---|---|---|---|---|---|---|---|---|
\(\alpha_{t}\) | 2.34 | 2.33 | 1.85 | 1.13 | 1.69 | 2.36 | 2.57 | 1.21 | 1.11 |
R2 | 0.998 | 0.996 | 0.996 | 0.997 | 0.997 | 0.997 | 0.975 | 0.998 | 0.998 |
Specimen no. | \(V_{FF1}\)/% | \(V_{FF2}\)/% | \(V_{CF}\)/% | \(\lambda_{i}\) | \(\lambda_{j}\) | \(\lambda_{k}\) |
---|---|---|---|---|---|---|
A0 | 0 | 0 | 0 | 0 | 0 | 0 |
A1 | 0.099 | 0 | 0 | 0.72 | 0 | 0 |
A2 | 0 | 0.099 | 0 | 0 | 0.188 | 0 |
A3 | 0 | 0 | 0.632 | 0 | 0 | 0.395 |
A4 | 0.066 | 0 | 0.568 | 0.48 | 0 | 0.355 |
A5 | 0.099 | 0 | 0.537 | 0.72 | 0 | 0.336 |
A6 | 0.132 | 0 | 0.505 | 0.96 | 0 | 0.316 |
A7 | 0.049 | 0.049 | 0.537 | 0.36 | 0.094 | 0.336 |
A8 | 0.066 | 0.066 | 0.505 | 0.480 | 0.125 | 0.316 |
Mechanical indexes | The enhancement coefficient \(W\) of PFRCC | \(R^{2}\) |
---|---|---|
\(f_{t}\) | \(\begin{gathered} W_{{f_{t} }} = 1{ + 0}{\text{.0907}} \times \lambda_{i} { + }1.0588 \times \lambda_{j} { + }1.0618 \times \lambda_{k} - {0}{\text{.063}} \times \lambda_{i}^{2} \hfill \\ \, - {2}{\text{.816}} \times \lambda_{j}^{2} - {1}{\text{.344}} \times \lambda_{k}^{2} - {0}{\text{.824}} \times \lambda_{i} \lambda_{j} { + 4}{\text{.064}} \times \lambda_{j} \lambda_{k} \hfill \\ \, - {0}{\text{.520}} \times \lambda_{k} \lambda_{i} - {5}{\text{.243}} \times \lambda_{i} \lambda_{j} \lambda_{k} \hfill \\ \end{gathered}\) | 0.999 |
\(\varepsilon_{t}\) | \(\begin{gathered} W_{{\varepsilon_{t} }} = 1 + 0.3744 \times \lambda_{i} + 1.2946 \times \lambda_{j} + 0.8485 \times \lambda_{k} - {0}{\text{.260}} \times \lambda_{i}^{2} \hfill \\ \, - {3}{\text{.443}} \times \lambda_{j}^{2} - {1}{\text{.074}} \times \lambda_{k}^{2} + 1.741 \times \lambda_{i} \lambda_{j} - {4}{\text{.064}} \times \lambda_{j} \lambda_{k} \hfill \\ \, + 1.637 \times \lambda_{k} \lambda_{i} - {0}{\text{.075}} \times \lambda_{i} \lambda_{j} \lambda_{k} \hfill \\ \end{gathered}\) | 0.988 |
\(\alpha_{t}\) | \(\begin{gathered} W_{{\alpha_{t} }} = 1 - 0.0605 \times \lambda_{i} - 2.2195 \times \lambda_{j} - 2.7421 \times \lambda_{k} + 0.042 \times \lambda_{i}^{2} \hfill \\ \, + 5.903 \times \lambda_{j}^{2} + 3.471 \times \lambda_{k}^{2} - 1.678 \times \lambda_{i} \lambda_{j} + 4.353 \times \lambda_{j} \lambda_{k} \hfill \\ \, + 2.089 \times \lambda_{k} \lambda_{i} - {10}{\text{.035}} \times \lambda_{i} \lambda_{j} \lambda_{k} \hfill \\ \end{gathered}\) | 0.798 |
\(E_{c}\) | \(\begin{gathered} W_{{E_{c} }} = 1 + 0.0547 \times \lambda_{i} + 0.4674 \times \lambda_{j} + 0.1311 \times \lambda_{k} - {0}{\text{.038}} \times \lambda_{i}^{2} \hfill \\ \, - {1}{\text{.243}} \times \lambda_{j}^{2} - {0}{\text{.166}} \times \lambda_{k}^{2} + 0.827 \times \lambda_{i} \lambda_{j} + 2.621 \times \lambda_{j} \lambda_{k} \hfill \\ \, - 0.154 \times \lambda_{k} \lambda_{i} - {12}{\text{.991}} \times \lambda_{i} \lambda_{j} \lambda_{k} \hfill \\ \end{gathered}\) | 0.979 |