种类不同

• In view of some problems appearing frequen tly in use of expansive agent in recent years , it is necessary to study factors influencing the effectiveness of expansive agent , such as water to cement ratio lower than 0 . 4 , varying dosages of various mineral admixtures in concrete , hig h temperature in mass concrete , restrained level in structure , etc
  鉴于近年来在膨胀剂的使用中不断出现问题，有必要对影响膨胀剂效用的因素，例如低于0 . 4水灰比的影响、不同种类不同矿物掺和料的影响、大体积混凝土中温度的影响以及结构中约束条件的影响等。