0
$\begingroup$

Assumptions
Building Process exists
Waterproofing is able to be replaced

Notes

  • Please answer yes or no with the science backing.
  • This question is only about the strength and lifespan.

  • This question is NOT about cost, or process.

  • Additional material may be required. Please include in your answer if it can overcome an obstacle.

Potentially Relevant Values

Compressive Strengths:
Granite: ~200MPa
Concrete: ~70MPa

$\endgroup$
9
  • 1
    $\begingroup$ What have you researched / found so far? So we don’t repeat and waste effort, ie we make a suggestion then you torpedo us with “I considered that but...”... $\endgroup$ – Solar Mike Mar 1 '19 at 5:09
  • 1
    $\begingroup$ I suggest you research how tunnels are actually built (there's more than one way of course), then the advanteges of concrete become more apparent. $\endgroup$ – mart Mar 1 '19 at 7:57
  • 1
    $\begingroup$ How waterproof does this tunnel need to be? (The joints between granite blocks is a critical point.) $\endgroup$ – ingenørd Mar 1 '19 at 9:11
  • $\begingroup$ Welcome to Engineering! This looks like a 'Novel Idea' question. Such questions tend to become moving targets and lead to discussions, neither of which are a good fit for our format. See if you can edit your question to make it specific and answerable. $\endgroup$ – Wasabi Mar 1 '19 at 13:16
  • 1
    $\begingroup$ If your interest lies in increasing service life, the questions you might want to back up and tackle first are (1) what factors currently determine tunnel service life? (2) Does granite actually improve any of these considerations/conditions? Seems a bit like you’re diving into analyzing the bark before determining whether you’re even in the right forest. $\endgroup$ – CableStay Mar 2 '19 at 13:15
1
$\begingroup$

It is possible to use granite instead of concrete in construction (remember that buildings were made out of stone long before concrete was invented), but only in those instances where the structure is guaranteed to never experience tensile stresses.

By reinforcing the concrete with prestressed steel rods, it is possible to render the resulting structure resistant to tensile loads as well- something which cannot be done with granite blocks.

Careful preparation of concrete results in uniform properties. Blocks of granite, being natural products mined out of the earth's crust, can possess faults, cracks and inhomogenieties which compromise their structural integrity in a way that is out of the designer's control.

I know of no way to reinforce granite blocks with any sort of nanomaterials.

$\endgroup$
9
  • $\begingroup$ Concrete can also have non-uniform properties, mixing issues, filling times etc - it may not be the “perfect” material... $\endgroup$ – Solar Mike Mar 1 '19 at 6:25
  • $\begingroup$ yeah, so a good batch has to be carefully prepared, if the resulting structure is to be sound. $\endgroup$ – niels nielsen Mar 1 '19 at 6:31
  • 1
    $\begingroup$ low quality question. $\endgroup$ – kamran Mar 1 '19 at 8:25
  • 1
    $\begingroup$ but a suitable answer, yes? $\endgroup$ – niels nielsen Mar 1 '19 at 18:52
  • $\begingroup$ @nielsnielsen great answer! regarding the reinforcing the granite: there may be opportunity to reinforce the granite with prestressed cords or outer layer of a high yield strength material such as graphene. $\endgroup$ – Dev Slocum Mar 2 '19 at 4:02

Not the answer you're looking for? Browse other questions tagged or ask your own question.