(gÉrÄ­l`É) [Span.,=little war], fighting by groups of irregular troops (guerrillas) within areas occupied by the enemy. When guerrillas obey the laws of conventional warfare they are entitled, if captured, to be treated as ordinary prisoners of war; however, they are often executed by their captors.
The Inside Story â Concrete Is Porous. Most people do not realize that concrete is porous â more porous than Swiss cheese! The pores constitute 12 â 18% or more of the concrete but they are invisible, much smaller than the diameter of human hair. After new concrete is poured, almost half of the water has to evaporate.
Why Cinder Block Walls Leak. Cinder blocks are more porous than standard concrete blocks or poured concrete. Only a thin wall (1-1/4 inch) separates the hollow core of concrete blocks from wind-driven rain or water-soaked ground and, after the core fills up with water, from the indoor space.