Crystal silicon not steel, but it&#x27;s reasonably close to concrete.  And concrete is the high end road surface vs. asphalt.<p>Crystal silicon [.6 - 1.3KIc (MPa · m1&#x2F;2)] <a href="https:&#x2F;&#x2F;lirias.kuleuven.be&#x2F;bitstream&#x2F;123456789&#x2F;355152&#x2F;1&#x2F;Thermomechanical+properties+and+fracture+in+single+crystal+silicon+-+REVIEWED.pdf" rel="nofollow">https:&#x2F;&#x2F;lirias.kuleuven.be&#x2F;bitstream&#x2F;123456789&#x2F;355152&#x2F;1&#x2F;Ther...</a>   (Page 12)<p>Concrete [0.2-1.4 KIc (MPa · m1&#x2F;2)] <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Fracture_toughness" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Fracture_toughness</a>