Test sequence for sandstone consolidation products

    **** Moderator's comments:  In Conservation DistList Instance:
    30:1 Sunday, May 22, 2016, in a announcement "Studentship at
    Centre for Doctoral Training Science and Engineering in Arts,
    Heritage and Archaeology (SEAHA)" Julie Eklund
    <julie.eklund<-at->ouce<.>ox<.>ac<.>uk> described a studentship with the
    theme "Improving the evaluation of conservation treatments for
    deteriorating sandstone in built heritage".  The current message
    is in response to that.

>Many of the world's greatest built heritage sites are crafted in
>sandstone, which often deteriorates rapidly posing major challenges
>for conservators.  Many treatments have been proposed (such
>as consolidants, water repellents and anti-graffiti coatings).
>What is now needed is to develop a robust methodology to test
>the performance of these treatments under real-world conditions.
>This studentship addresses this knowledge gap, through a developmental
>sequence of laboratory and field experiments. ...

I developed a test sequence for evaluating sandstone consolidants as
part of a Masters thesis at the University of Technology, Sydney
between 1997-2000 using sample cores 15cm (L) x 2cm (D).
Non-destructive tests including NMR to determine porosity and
permeability were conducted on a single core before it was
sub-divided into three smaller cores for ultra sound tests.
Following ultra sound, the cores were then used for compressive
strength tests.  The remnants were progressively used for
petrography, ESEM, infrared analysis, thermal expansion analysis and
x-ray diffraction analysis using smaller sample sizes derived from
original cores with a view to patching holes in the buildings with
the core remnants mixed with adhesive.

Following desalination using a paper poulticing product developed by
another student at UTS, three products were tested including
Tegavakon V, a metal catalysed silica skin developed by Alan
Watchman and another silica skin product catalysed using glycolic
acid.  The outcome of my thesis was inconclusive as the penetration
depth of the consolidants was only 2-3mm using a brush on technique.
I was interested in developing a porous product which worked like
Goretex keeping water out while allowing trapped salts to effloresce
in the absence of damp proof courses in early Sydney sandstone
buildings.  I did not progress to the next step to conduct some
reverse osmosis tests on the products.

I still have some sample cores left over from my research should a
student wish to progress the work.  My thesis was sponsored by UTS
and the Department of Public Works Sydney.  A copy of my thesis is
held in the University of Technology, Sydney library.

Julie O'Connor
Conservation Solutions


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                  Conservation DistList Instance 30:2
                  Distributed: Saturday, May 28, 2016
                        Message Id: cdl-30-2-002
                                  ***