I provide these comments without the benefit of direct experience - our first pizza is scheduled for tonight! - but with some knowledge of heat transfer...
"Recharge" of the floor should certainly be accelerated by the fire, but if the oven has reached equilibrium as shown in James' cartoon in the first post, the surface should also re-charge from heat spreading back from the depth of the floor. In other words, as soon as the surface cools due to heat transferred to the pizza, the surface will be cooler than the deeper portions of the floor and stored heat will move back toward the surface.
Anyone who has an infrared thermometer and a thermocouple at some depth into the floor should see the surface temp down a little after the pie is removed, and, of the fire is down, the surface temp recovering at the expense of a drop in temp at the "depths," followed by the two temperatures moving toward each other.
As others have discussed throughout the site in determining material choices, there's a balance between thermal mass that provides heat storage and thermal conductivity that allows stored heat to promptly become available for cooking.  |