I write this on April Fools day because it seems as though I am in the middle of an elaborate prank. I field a lot of calls in this newly evolving business where I create all sorts of useful and decorative items from concrete. People want to know if Liquid Quarry can colour it, if it resists staining, can it be repaired if someone chips it - to which the answer is yes to all. For the past week I am getting calls from people needing to know how heavy Liquid Quarry GFRC concrete is. At about 9 pounds per square foot it is similar to granite and thin marble. Although I get this question often, and I get it that people think "sidewalk" when they hear the word concrete, it is that almost every call I have had recently begins with "How much does it weigh?" and "Will I need to reinforce under it?" There will not be a cement truck in your driveway with a chute coming through your kitchen window.
Nope. Glass fibre reinforced concrete at 3/4 of an inch thick is so strong that your drunk uncle can dance on the kitchen island all night. If you reinforce, do it for him!