natural freezing method meaning in Chinese

天然冻结法

With using once artificial freezing method and natural freezing method test the compressive strength of low - temperature concrete at different age and by testing the loss percentage of water ( content of evaporative water ) of saturated specimen test the pore porosity of low - temperature concrete at different age
方法采用恒低温一次冻结法和自然变低温多次冻结法，测定混凝土在不同龄期的强度值，利用可蒸发水含量法测定对应龄期的孔隙率。