We have discussed about advantages of high range water reducing admixtures for concrete in our last post. In every system or material there have some disadvantages too. But proper and optimum application makes them advantageous and economical. Here in this post we will have some disadvantage of high range water reducing admixtures.
Though strength of concrete in hardened state is higher when high range water reducing admixtures used than normal concrete because of lower water/cement ratio, there have some limitation also. Here we are listing some disadvantages according to National Ready Mixed Concrete Association:
Disadvantages of applying high range water reducing admixtures:
a. Inclusion of additional cost for admixture
b. Slump loss is usually greater than traditional concrete.
c. It is required to change or modify the dosages of air entraining admixtures.
d. They don’t comply with some types cement i.e. show less response to some cement
e. Slight discoloration of concrete is noticed with they are designed to have light-color.
f. In case of formed finishing or exposed finishing color blemishes and air voids are observed.
So from the advantages and disadvantages we can conclude that good knowledge about performance of base material is required in choosing correct admixture. So, specific types of admixtures should be chosen from specific requirements and conditions of jobsite.
ACI E4-03 discusses about three types of ingredients as high range water reducing admixtures. We will discuss suitability of each type for specific job conditions in our upcoming post.