The best way to consider this test is as an accelerated weathering test, which reflects the integrety and porosity of a rock to resist weathering. As in many tests, its not so much about identifying a finite value, but providing a comparable value which can be used to distinguish between suitable and unsuitable materials. Although your material may not be subject to freeze/thaw activity or wetting/drying of salt water, the relationaship between 'more durable' and 'less durable' rocks would still provide a valid comparison and could form the basis of selection of a suitable source.
I would hope that the values you are required to meet reflect this, and not that this reqirement has been selected indiscriminantly by including all test requirments from specifications that in turn may not have been written with your site/country in mind.