Methods of testing concrete, Method 4.2: Determination of air content of freshly mixed concrete - Measuring reduction in air pressure in chamber above concrete
混凝土试验方法 方法4.2:新拌混凝土中空气含量的测定-测量混凝土上方腔室中空气压力的降低
This Standard sets out the method for determining the air content of freshly mixed concrete from observations of the reduction in air pressure in a chamber above the concrete when the concrete is exposed to the air pressure.