ABSTRACT
This chapter is about the different types of chemical admixtures that you should use for the improvement of concrete properties. Some of them like the super-plasticizers are necessary for the production of high-quality concrete. So, first the subject of reasons for using chemical admixtures is described.
The first type of chemical admixture mentioned in this chapter is the accelerators. Different types of accelerators like set accelerators and hardening accelerators and also the antifreeze admixtures and shotcrete accelerators are mentioned.
Retarder admixtures are the next type of chemical admixtures that are introduced in this chapter. Choosing the dosage for the retarders is a very important and sometimes complicated subject which is discussed here.
The most important types of chemical admixtures as the plasticizers and super-plasticizers are the next subjects mentioned in this chapter. The admixtures in ASTM standard and different chemical bases of plasticizers and super-plasticizers are the next subjects of this chapter. Necessary tests for the quality control of super-plasticizers which are mini slump test, marsh funnel test, and concrete trials and the process of obtaining water reduction curve for the super-plasticizers which is necessary for concrete mix design are also described.
In the last part of this chapter, air-entraining admixtures and their effect on the freeze-thaw resistance of concrete are mentioned. Then the waterproofing admixtures and making watertight structures are discussed. Curing compound admixtures and the importance of concrete curing and finally, the viscosity modifying admixtures, pumping aid admixtures, and foaming agent admixtures are described.
