开放孔隙 meaning in Chinese

open space

Natural stone test methods . determination of real density and apparent density , and of total and open porosity
天然石材的试验方法.实密度表观密度总孔隙率和开放孔隙率的测定
Methods of test for masonry units - determination of real and bulk density and of total and open porosity for natural stone masonry units
砖石结构体的试验方法.天然石头砖砌结构体的实际密度和体积密度及总孔隙度和开放孔隙度的测定