How heavy are Conkeldurr's pillars?

Conkeldurr is 4'07" or 138 pixels tall.

Conkeldurr's left pillar is 131 pixels tall, or 52 inches tall.

The radius of Conkeldurr's left pillar is 56 pixels, or 22 inches wide.

The volume of a cylinder is:
V=πr2h
π(22)2(52)=79067.6

Using a concrete weight calculator, 79067.6 cubic inches of concrete weighs 6,863.5 pounds.

One concrete pillar weighs 6863.5 pounds, or 3.1 metric tons.