【名词&注释】
抗压强度(compressive strength)、外加剂(admixture)、功能性(functionality)、引气减水剂(air-leading water-reducing agent)、缓凝高效减水剂、早强减水剂(early strength water-reduced agent)、缓凝减水剂(water-reducing retarder)
[单选题]以各种高效减水剂为主要组分,再复合各种适量的缓凝组分或其他功能性组分而成的外加剂是()
A. 早强减水剂(early strength water-reduced agent)
B. 引气减水剂
C. 缓凝高效减水剂
D. 缓凝减水剂(water-reducing retarder)