减水剂

这些外加剂减少了混凝土混合物中所需的水量，同时保持了和易性. 这可以带来几个好处, 包括增加力量, 提高耐用性, 并减少收缩. 减水剂主要有两种类型: 高效减水剂 (HRWR) 和中档减水剂 (MRWR).

设置缓速器

这些外加剂会减慢混凝土的凝固时间. 这在炎热天气或需要长时间工作时很有帮助.

速凝外加剂

这些外加剂可加快混凝土的凝固时间. 这在寒冷的天气或需要早期力量时很有帮助.

这些促进剂还通过提高水化速率来增强混凝土的早期强度. 事实证明，早期混凝土硬化在多种情况下是有益的, 例如早期拆除模板, 缩短固化时间, 紧急抢修, 以及低温地区的建筑. 一些常见的促进混合物包括三乙醇胺, 甲酸钙, 微硅粉, 氯化钙, 并细细划分 微硅粉. Among these, calcium chloride is the cheaper and more commonly used accelerating admixture.

Air entrainers

These admixtures introduce tiny air bubbles into the concrete. These air bubbles help to improve the concrete’s resistance to freezing and thawing.

高效减水剂

These are high-range water reducers that can significantly reduce the amount of water needed in a concrete mix. This can lead to very high-strength concrete with improved workability.

Workability admixtures

这些外加剂可改善混凝土的和易性, 使其更容易放置和完成. There are several types of workability admixtures, including air-entraining admixtures, water reducers, and retarders.

Corrosion inhibitors

These admixtures help to protect steel reinforcement in concrete from corrosion.

Shrinkage reducers

These admixtures reduce the amount of shrinkage that occurs in concrete as it cures. This can help to reduce cracking.

Fibers

Fibers are small, discrete strands of reinforcing material that are added to concrete to improve its strength, 韧性, and crack resistance. There are two main types of fibers: steel fibers 和合成纤维.

着色外加剂

这些外加剂为混凝土添加颜色. 它们可用于美观目的或提高可见度.

着色混合物及其所得颜色

这些只是可用的许多不同类型的混凝土外加剂中的一些. 所使用的外加剂的具体类型取决于混凝土的所需性能.