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Interface shear properties from A9 Cairnleith Moss trial section 8 February 2011 Ooms Nederland Holding bv
Interface shear properties from A9 Cairnleith Moss trial section
8 February 2011
Ooms Nederland Holding bv
Ooms Nederland Holding bv
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Client: Material Edge Ltd Tel: +44 1625 861808 Fax: +44 161 332 8200 www.materialedge.co.uk Contact: C. Sullivan Prepared by: Ooms Nederland Holding bv R&D Laboratory P.O. box 1 1633 ZG Avenhorn The Netherlands Tel: +31 229 547700 Fax: +31 229 547234 www.ooms.nl/research Contact: Dr.ir. A.H. de Bondt ([email protected]) Project number: 100043-8
Version Date Prepared by Approved by
Final
8 February 2011
Ir. C.P. Plug Dr.ir. A.H. de Bondt
Liability This report indicates the current position in terms of technology and knowledge at the time of publication. Ooms Nederland Holding bv (ONH) has taken the greatest possible care in compiling this report to ensure its correctness. However, the possibility that some information in this report may be incorrect and/or incomplete cannot be ruled out. ONH shall not be liable for loss or damage, which is not attributable to gross negligence or intention on the part of ONH (including its employees). ONH shall at no time be liable to pay compensation in an amount, which exceeds the nominal invoice value of the goods delivered and/or services rendered in respect of which compensation is claimed. Any compensation for loss or damage shall be expressly limited to direct loss. Any right to compensation for loss or damage shall be conditional on the customer having notified ONH of the loss or damage in writing within one month of the loss or damage occurring, or of the moment at which the client could reasonably be expected to have been aware of said loss or damage. Copyright All rights reserved by ONH. No part of this report may be reproduced, stored in a database or retrieval system or published, in any form or in any way, electronically, mechanically, by print, photoprint, microfilm or any other means without prior written permission from ONH. Pursuant to Section 15a of the Dutch Copyright Act 1912 (Auteurswet 1912), it is permitted to cite parts of this report in articles, dissertations and books, provided the source is clearly stated, as well as the name and marks of the maker, if these occur in the source. Scharwoude, March 1998 The Board of Management, Ooms Nederland Holding bv
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Introduction Nine ø150 mm cores with an asphalt surface course on a lean concrete base course from the A9 Cairnleith Moss / Bankfoot trial section in the UK were delivered at the central laboratory of Ooms Nederland Holding in the Netherlands in December 2010. In this trial three construction types were laid down on a lean concrete base (from top to bottom): Construction type A:
• 40 mm Surface course on top of tack coat (k1 40)
• 100 mm Base course
• Bond coat (k1 40) 0.4-0.5 kg/m2
• Lean concrete base Construction type B:
• 40 mm Surface course on top of tack coat (k1 40)
• 100 mm Base course
• 4-6 kg/m2 crushed stones • SAMI 2 kg/m2 (Sealoflex SC 4)
• Bond coat (k1 40) 0.4-0.5 kg/m2
• Lean concrete base Construction type C:
• 40 mm Surface course on top of tack coat (k1 40)
• 100 mm Base course
• 4-6 kg/m2 crushed stones
• SAMI 2 kg/m2 (Sealoflex SC 4) • Lean concrete base
Only from construction type B and C cores were received. Details of the cores are given in appendix A. The shear properties of the cores were tested at the interface using the modified Leutner device. Test program Leutner shear tests (MCHW_1 clause 954) were carried out on all nine cores. The test temperature was 20 ± 1 °C and the rate of displacement 0.85 mm/s (51 mm/min). Before testing the cores were thoroughly cleaned from smeared bitumen around the interface. This to enable the placement of the interface of the core exactly in the middle of the 5 mm gap of the modified Leutner device. The modifications to the Leutner device were first made by De Bondt at the Delft University of technology. The gap between the clamps of the mould was increased from a negligible distance to 5 mm; this to enable the positioning of the interfaces to be done much more easily and thus accurately. This action implies that the steel piston is not exactly on top of the layer interface anymore: there is 2.5 mm space between both centres. As expected, the effect of this spacing on the mechanics of the set-up was found to be negligible. This is due to the fact that the reaction forces are spread over a certain area of the core. The tests were continued till a total (shear) displacement of 9 mm, being the maximum possible displacement of the test set-up. From the test data the maximum peak load (force); the peak shear strength, the displacement at shear strength, the shear energy till 5 mm displacement and the interface shear stiffness modulus at strength were calculated.
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Results The diameter of the delivered cores were larger than specified (Ø 150 ± 2 mm). Nevertheless, the cores could be tested. The test results for the cores from section B are summarised in table 1. The cores from section C are summarised in table 2. The measurement curves are given on the next page.
Table 1: Summary of results of Leutner Interface Shear Tests (B section)
Core Diameter Peak load Shear
strength
Slip at shear
strength
Energy till 5 mm
Shear stiffness modulus
[mm] [kN] [MPa] [mm] [N/mm] [MPa/mm]
B247S/B 153.3 12.1 0.65 4.9 1.9 0.13 B275S/B 153.9 10.2 0.55 5.4 1.1 0.10 B222N/B 153.0 10.0 0.54 4.6 1.8 0.12 B247N/B* 153.3 11.1 0.60 5.0 1.4 0.12 B274N/B 153.2 12.1 0.66 3.5 1.4 0.19 B276S/B 153.4 12.6 0.68 4.0 1.5 0.17
Average - 11.1 0.60 4.7 1.5 0.13 COV [%] - 9 9 16 21 26
*] Both layers did not debond at the end of the test
Table 2: Summary of results of Leutner Interface Shear Tests (C section)
Core Diameter Peak load Shear
strength
Slip at shear
strength
Energy till 5 mm
Shear stiffness modulus
[mm] [kN] [MPa] [mm] [N/mm] [MPa/mm]
C350S/B 153.2 6.8 0.37 4.0 1.1 0.092 C318N/B 152.8 8.0 0.44 3.0 1.5 0.14 C349S/B 153.2 6.1 0.33 2.6 1.1 0.13
Average - 7.0 0.38 3.2 1.3 0.12 COV [%] - 13 14 23 19 22
Discussion Despite the out of spec diameters of the cores, the coefficient of variation (COV) of the measurement results for both sections is relatively low. This is indicating that the results are accurate. Furthermore, it can be seen from the results that applying a bond coat (emulsion) under the SAMI will give an improvement of the interface shear strength.
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0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
0 1 2 3 4 5 6 7 8 9
Displacement [mm]
Sh
ea
r F
orc
e [
kN
]
B247S/B B275S/B B222N/B B247N/B B274S/B B276S/B
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
0 1 2 3 4 5 6 7 8 9
Displacement [mm]
Sh
ear
Fo
rce [
kN
]
C350S/B C318N/B C349S/B
Detailed test results In figures 1 and 2, the shear force against displacement for the B, respectively the C section are displayed. Pictures of the cores after testing are shown in figures 3 and 4.
Figure 1: Measured shear force against displacement B cores.
Figure 2: Measured shear force against displacement C cores.
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Picture 3: Cores from section B after testing.
Picture 4: Cores from section C after testing.
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Appendix A – Details location cores
