Figure 1:
Grain size distribution curve of tested soil.
Figure 2:
Different lengths (and diameters) of fibres in the amount of 0.2% in reference to the dry mass of the sample that was added to the coarse soil: a) 12 mm (0.030 mm), b) 18 mm (0.034 mm), c) 40 mm (0,90 mm).
Figure 3:
Soil mixed mechanically with fibres: a) 40 mm long; b) 18 mm long.
Figure 4:
Compaction curves of gravelly sand and gravelly sand with 1.5% of cement addition compacted by two methods: a) SP, b) MP.
Figure 5:
Compaction curves of gravelly sand with different amounts of fibres 18 mm long compacted by two methods: a) SP, b) MP.
Table 1:
The specific density and compaction parameters of tested materials.
| Sample | ρs(Mg/m3) | Proctor compaction method | |||
|---|---|---|---|---|---|
| Standard | Modified | ||||
| wopt (%) | ρd max (Mg/m3) | wopt (%) | ρd max (Mg/m3) | ||
| grSa | 2.65 | 9.7 | 1.974 | 9.6 | 2.022 |
| grSa+1.5%C | 2.66 | 9.5 | 2.010 | 9.5 | 2.070 |
| grSa+1.5%C+0.2%F_12 mm | 2.66 | 9.4 | 2.075 | 7.9 | 2.150 |
| grSa+1.5%C+0.3%F_12 mm | 2.66 | 8.9 | 2.103 | 6.8 | 2.170 |
| grSa+1.5%C+0.2%F_18 mm | 2.66 | 7.9 | 2.066 | 7.0 | 2.183 |
| grSa+1.5%C+0.3%F_18 mm | 2.66 | 8.0 | 2.060 | 7.8 | 2.124 |
| grSa+1.5%C+0.2%F_40 mm | 2.66 | 8.8 | 2.108 | 7.5 | 2.144 |
[i] where: C – cement addition, F – fibre addition
Figure 6:
Principle of triaxial testing with cyclic loading
Figure 7:
Sample behaviour under cyclic loading in a triaxial cell during one of the initial cycles of the 15th sequence subjected to grSa+1.5%C+0.3%F_18 mm sample compacted with SP method.
Figure 8:
Sample behaviour subjected to cyclic loading/unloading in the triaxial cell during 100 cycles of the 15th sequence for grSa+1.5%C+0.3%F_18 mm sample compacted SP method, tested after 7 days of curing.
Figure 9:
Resilient modulus Mr values obtained after 7 and 28 days of curing for samples with 1.5% cement and 0.2% fibres of different lengths compacted by: a) SP method; b) MP method.
Figure 10:
Resilient modulus Mr values obtained after 7 and 28 days of curing for samples with 1.5% cement and 0.3% fibres of different lengths compacted by: a) SP method; b) MP method.
Table 2:
Values of Mr obtained for samples after different compaction and curing periods.
| Samples | Resilient modulus Mr (MPa) | Curing period | |
|---|---|---|---|
| SP compaction | MP compaction | (days) | |
| grSa+1.5%C | 197 | 168 | 7 |
| 272 | 353 | 28 | |
| grSa+1.5%C+0.2%F_12 mm | 73 | 165 | 7 |
| 162 | 177 | 28 | |
| grSa+1.5%C+0.3%F_12 mm | 193 | 224 | 7 |
| 178 | 236 | 28 | |
| grSa+1.5%C+0.2%F_18 mm | 271 | 215 | 7 |
| 202 | 230 | 28 | |
| grSa+1.5%C+0.3%F_18 mm | 301 | 226 | 7 |
| 214 | 241 | 28 | |
| grSa+1.5%C+0.2%F_40 mm | 51 | 140 | 7 |
| 145 | 153 | 28 | |
Figure 11:
Mr values of samples tested after 7 days of curing compacted by SP method with different fibres content: a) grSa+1.5%C+0.2%F_18 mm b) grSa+1.5%C+0.3%F_18 mm.
Figure 12:
Mr values of samples tested after 7 days of curing compacted by MP method with different fibres content: a) grSa+1.5%C+0.2%F_18 mm b) grSa+1.5%C+0.3%F_18 mm.
Figure 13:
Mr values of samples tested after 7 days of curing compacted by SP method with different fibres content: a) grSa+1.5%C+0.2%F_12 mm b) grSa+1.5%C+0.3%F_12 mm.
Figure 14:
Mr values of samples tested after 7 days of curing compacted by MP method with different fibres content: a) grSa+1.5%C+0.2%F_12 mm b) grSa+1.5%C+0.3%F_12 mm.