sr241a - corrosion of fasteners

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STUDY REPORT

SR 241 A(2011)

Corrosion of Fasteners

in Treated Timber

Appendix

Z.W. Li, N.J. Marston and M.S. Jones

The work reported here was funded by BRANZ from the Building Research Levy,whose logo is shown above.

BRANZ 2011ISSN: 1179-6197


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Corrosion of Fasteners in Treated Timber - Appendix

BRANZ Study Report SR 241A

Z.W. Li N.J. Marston and M.S. Jones

Reference

Li ZW, Marston NJ and Jones MS. 2011. Corrosion of Fasteners in Treated Timber -Appendix. BRANZ Study Report 241. BRANZ Ltd, Judgeford, New Zealand.


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Contents Page

APPENDIXPHOTO GALLERY ............................................................................................................... 1

A.1 Metallic Fixing Components Exposed at Judgeford .................................................................................. 1

A.1.1 Mild Steel Components ....................................................................................... 1A.1.1.1 Untreated Timber .................................................................................... 1A.1.1.2 H3.2 CCA Treated Timber....................................................................... 2A.1.1.3 H4 CCA Treated Timber ......................................................................... 2A.1.1.4 H3.2 CuAz Treated Timber ..................................................................... 3A.1.1.5 H4 CuAz Treated Timber ........................................................................ 4A.1.1.6 H3.2 ACQ Treated Timber ...................................................................... 4A.1.1.7 H4 ACQ Treated Timber ......................................................................... 5

A.1.2 Galvanised Steel Components ............................................................................ 6A.1.2.1 Untreated Timber .................................................................................... 6A.1.2.2 H3.2 CCA Treated Timber ...................................................................... 7A.1.2.3 H4 CCA Treated Timber ......................................................................... 8

A.1.2.4 H3.2 CuAz Treated Timber ..................................................................... 9A.1.2.5 H4 CuAz Treated Timber .......................................................................10A.1.2.6 H3.2 ACQ Treated Timber .....................................................................11A.1.2.7 H4 ACQ Treated Timber ........................................................................12

A.1.3 Stainless Steel Components ..............................................................................13A.1.3.1 Untreated Timber ...................................................................................13A.1.3.2 H3.2 CCA Treated Timber......................................................................14A.1.3.3 H4 CCA Treated Timber ........................................................................15A.1.3.4 H3.2 CuAz Treated Timber ....................................................................16A.1.3.5 H4 CuAz Treated Timber .......................................................................17A.1.3.6 H3.2 ACQ Treated Timber .....................................................................18A.1.3.7 H4 ACQ Treated Timber ........................................................................19

A.2 Metallic Fixing Components Exposed at Oteranga Bay ...................................................................... 20A.2.1 Mild Steel Components ......................................................................................20

A.2.1.1 Untreated Timber ...................................................................................20A.2.1.2 H3.2 CCA Treated Timber......................................................................20A.2.1.3 H4 CCA Treated Timber ........................................................................21A.2.1.4 H3.2 CuAz Treated Timber ...................................................................22A.2.1.5 H4 CuAz Treated Timber .......................................................................22A.2.1.6 H3.2 ACQ Treated Timber .....................................................................23A.2.1.7 H4 ACQ Treated Timber ........................................................................23

A.2.2 Galvanised Steel Components ...........................................................................24A.2.2.1 Untreated Timber ...................................................................................24

A.2.2.2 H3.2 CCA Treated Timber......................................................................24A.2.2.3 H4 CCA Treated Timber ........................................................................25A.2.2.4 H3.2 CuAz Treated Timber ....................................................................26A.2.2.5 H4 CuAz Treated Timber .......................................................................27A.2.2.6 H4 ACQ Treated Timber ........................................................................28

A.2.3 Stainless Steel Components ..............................................................................29A.2.3.1 Untreated Timber ...................................................................................29A.2.3.2 H3.2 CCA Treated Timber......................................................................30A.2.3.3 H4 CCA Treated Timber ........................................................................31A.2.3.4 H3.2 CuAz Treated Timber ....................................................................32A.2.3.5 H4 CuAz Treated Timber .......................................................................33A.2.3.6 H3.2 ACQ Treated Timber .....................................................................34

A.2.3.7 H4 ACQ Treated Timber ........................................................................34


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APPENDIXPHOTO GALLERYNails and screws embedded into timbers after one-, two- and three-year exposureswere tested with corrosion rate measurement and surface morphologicalcharacterisation. Based on the results obtained, BRANZ believes that a three-yearexposure is not sufficient to determine the long-term durability (e.g. 15 and 50 years as

required by NZBC) of fastening and/or fixing components in treated timbers. The gate-shaped structures were therefore not completely dismantled to retrieve all thecomponents and they are exposed at Judgeford and Oteranga Bay for futurecharacterisation.

In this section, images showing the surface condition of bolts, brackets, nail plates andflashings after three years of exposure at Judgeford and Oteranga Bay were thenpresented to give the readers a rough picture on their deterioration. However it must beemphasised that these photos could only show the corrosion attack to the surfacedirectly exposed to the atmosphere. The influence of timber treatment (i.e. thecondition of the surface contacting timber) could not be revealed properly.

A.1 Metallic Fixing Components Exposed at JudgefordThe following images showing the hardware exposed at Judgeford site for three years.

A.1.1 Mild Steel Components

A.1.1.1 Untreated Timber


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A.1.1.2 H3.2 CCA Treated Timber

A.1.1.3 H4 CCA Treated Timber


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A.1.1.4 H3.2 CuAz Treated Timber


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A.1.1.5 H4 CuAz Treated Timber

A.1.1.6 H3.2 ACQ Treated Timber


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A.1.1.7 H4 ACQ Treated Timber


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A.1.2 Galvanised Steel Components



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A.1.3 Stainless Steel Components



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A.2 Metallic Fixing Components Exposed at Oteranga BayThe following images showing the hardware exposed at Oteranga Bay for three years.

A.2.1 Mild Steel Components




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A.2.2Galvanised Steel Components




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A.2.3Stainless Steel Components



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