1 Introduction
2 Pull out Test
2.1 Test Procedure
2.2 Test Material
Nominal diameter (d)/mm | Rib spacing (r)/mm | Rib depth (h)/mm | Ultimate tensile strength/MPa | Young’s modulus/GPa |
---|---|---|---|---|
6 | 8.12 | 0.75 | 830.5 | 96.2 |
8 | 8.02 | 0.26 | 873.5 | 98.1 |
10 | 9.02 | 0.36 | 919.8 | 105.4 |
12 | 8.70 | 0.28 | 779.4 | 82.6 |
16 | 12.53 | 0.64 | 870.1 | 97.8 |
20 | 14.91 | 0.24 | 935.5 | 113.1 |
Sieve size/mm | 4.75 | 9.5 | 13.2 | 16 | 19 | 26.5 | 31.5 |
By weight/% | 11.3 | 26.2 | 17.6 | 20.4 | 19.2 | 2.2 | 3.1 |
Bulk density (kg/m3) | Apparent density (kg/m3) | Porosity/% | 1 h water absorption/% | Compressive strength/MPa |
---|---|---|---|---|
983 | 1931 | 50.2 | 15.4 | 1.79 |
2.3 Test Specimens
Design strength of coral concrete | Water-cement ratio | Cement/kg/m3 | Coral aggregate/kg/m3 | Sand/kg/m3 | Seawater/kg/m3 |
---|---|---|---|---|---|
C15 | 0.53 | 340 | 716 | 830 | 180 |
C20 | 0.47 | 380 | 716 | 830 | 180 |
C30 | 0.40 | 450 | 716 | 830 | 180 |
Coral concrete strength | Cube compressive strength/MPa | Axial compressive strength/Mpa | Splitting tensile strength/Mpa |
---|---|---|---|
C15 | 15.83 | 12.77 | 1.33 |
C20 | 21.67 | 17.67 | 1.80 |
C30 | 32.27 | 26.73 | 2.60 |
2.4 Pull out Tests Set up
3 Test Results Analysis
3.1 Failure Mode and Bond-Slip (\(\tau{\text{-}}s\)) Relation
Test piece number | Nominal diameter/mm | Bond length/mm | Design strength of coral concrete/MPa | Fmax/kN | Smax/mm | τmax/MPa | Failure modes |
---|---|---|---|---|---|---|---|
B6-5d-C30 | 6 | 5d | C30 | 8.60 | 1.88 | 15.21 | P |
B8-5d-C30 | 8 | 5d | C30 | 15.10 | 1.66 | 15.03 | P |
B10-5d-C30 | 10 | 5d | C30 | 22.73 | 1.46 | 14.48 | P |
B10-10d-C30 | 10 | 10d | C30 | 41.25 | 1.40 | 13.14 | P |
B10-12d-C30 | 10 | 12d | C30 | 47.75 | 0.78 | 12.67 | F |
B12-5d-C30 | 12 | 5d | C30 | 32.10 | 2.84 | 14.20 | P |
B16-5d-C30 | 16 | 5d | C30 | 53.95 | 1.63 | 13.42 | S |
B20-5d-C30 | 20 | 5d | C30 | 66.05 | 2.39 | 10.52 | S |
B10-10d-C20 | 10 | 10d | C20 | 31.80 | 1.73 | 10.13 | P |
B10-10d-C15 | 10 | 10d | C15 | 26.25 | 1.46 | 8.36 | P |