(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.
Homeowners wishing to use a porous surface, such as gravel or permeable block paving, do not require planning permission, however. Additionally, no planning consent is required for existing driveways or new hard surfaces with controlled run-off to your garden or lawn.