1 Introduction
2 Experimental Program
2.1 Materials and Mixture Proportions
Composition | MgO | Fe2O3 | SiO2 | CaO | Others |
---|---|---|---|---|---|
Mass fraction of the sample (%) | 92.53 | 0.87 | 3.1 | 1.6 | 1.9 |
Sand to MPC mass ratio | Water to MPC mass ratio | MgO to KH2PO3 mol ratio | Retarder |
---|---|---|---|
0.8 | 0.14 | 4 | 9.0% |
Fibre profile | Type | Length (mm) | Equivalent diameter (mm) | Tensile strength (MPa) | Shape and surface | \(l_{p}\) (mm) | Nf |
---|---|---|---|---|---|---|---|
S-1 (Shanghai Realstrong Steel Fibre Co., Ltd. 2018) | 30 | 0.22 | 2850 | Straight, smooth, round | 9 | 4 | |
S-2 (Bekaert China Co., Ltd. 2018) | 30 | 0.75 | 1100 | Straight, smooth, round | 8 | 4 | |
H-1 (Shanghai Realstrong Steel Fibre Co., Ltd. 2018) | 38 | 0.22 | 2850 | Hooked, smooth, round | 9 | 4 | |
H-2 (Bekaert China Co., Ltd. 2018) | 35 | 0.54 | 1200 | Hooked, smooth, round | 9 | 2, 3, 4, 5 | |
R-H (Shanghai Harex Steel Fiber Technology Co., Ltd. 2018) | 32 | 0.91 | 600 | Hooked, roughened, flat | 9 | 3 | |
I-A (Zhitai Steel Fiber Co., Ltd. 2018) | 36 | 1.57 | 800 | Indented, round | 11 | 1 | |
C-A (Zhengzhou YuJian Steel Fiber Co., Ltd. 2018) | 40 | 1.26 | 600 | Crimped, FLAT | 10 | 1 |
2.2 Specimen Preparation
2.3 Test Procedure
3 Evaluation Parameters of Pullout Behaviour
4 Results and Discussion
Group | Compressive strength of matrix (MPa) | Maximum pullout load (N) | Maximum fibre tensile stress (MPa) | Average bond strength (MPa) | Pullout energy per unit volume (N mm/mm3) |
---|---|---|---|---|---|
S-1 | 37.4 | 174.1 | 1145.7 | 7.0 | 300.2 |
S-2 | 341.1 | 193.1 | 4.5 | 53.3 | |
H-1 | 346.9 | 2282.5 | 10.5 | 530.5 | |
H-2 | 733.8 | 801.4 | 12.0 | 173.1 | |
R-H | 1134.8 | 581.9 | 14.7 | 105.1 | |
I-A | 679.6 | 351.2 | 12.5 | 68.0 | |
C-A | 609.1 | 488.8 | 15.0 | 115.1 |
4.1 Effect of End-Hook Deformation
4.2 Effect of Diameter and Surface Coating of Fibres
4.3 Effect of Deformations Along Fibre Length and Rough Surface
4.4 Interface Transition Zone Between MPC and Varies Fibres
4.5 Summary of the Effect of Different Types of Fibre
4.6 Failure Modes of Pullout Steel Fibres Embedded in the MPC-Based Matrix
4.7 Group Effect of Steel Fibre on the Pullout Behaviour
Type of fibre | Compressive strength of matrix (MPa) | Spacing of fibres (mm) | Relative spacing | Maximum pullout load (N) | Maximum fibre tensile stress (MPa) | Average bond strength (MPa) | Pullout energy (N mm) | |
---|---|---|---|---|---|---|---|---|
Up to 2.5 mm | Up to 1.5 mm | |||||||
H-2 | 37.4 | 16 | 1.78 | 187.8 | 820.6 | 12.3 | 368.0 | 254.0 |
11 | 1.22 | 183.5 | 801.5 | 12.2 | 375.2 | 250.3 | ||
8 | 0.89 | 183.4 | 801.4 | 12.0 | 356.6 | 243.7 | ||
6 | 0.67 | 179.3 | 783.3 | 11.8 | 360.7 | 233.9 |