混凝土通常被认为是一种主要的工程材料之一。因此一些对混凝土质量有影响的因素如:强度、弹性模量和硬化强度等都必须达到有关质量标准。然而有些工程的混凝土质量较差,甚至从外表就可以看到。能改善混凝土吸水性质的材料通常都能改善混凝土的耐风化性、耐久性及外装饰性等。防水外加剂是典型的这种材料。 Concrete is generally considered as one of the major engineering materials. Therefore, some factors that affect the quality of concrete, such as strength, elastic modulus and hardening strength, must meet relevant quality standards. However, some projects have poor concrete quality and can even be seen from the outside. Materials that can improve the water absorption properties of concrete can generally improve the weather resistance, durability, and exterior decorative properties of the concrete. Water-repellent additives are typical of this material.