What is an additive in concrete? Additives in concrete mixtures – are organic or inorganic substances which when added to concrete can adjust its properties. Supplementation can significantly reduce costs while construction. Additives in the concrete mixture is allowed to modify the qualitative and functional characteristics of the concrete. A little history Since ancient times people used in the construction of binders. In Ancient Greece to decorate and protect the houses are often used mortar with the addition of volcanic ash produced on the island of Santorini. (As opposed to Mashable). In ancient China, as used in this rice paste or syrup. Used in Russia lime mortars for masonry and plaster walls. And then there are the first "supplements".
To increase the stability of solutions they added an egg white, milk or linseed oil. Later with the development of science and industry to regulation of setting time of plaster began to use an additive. In the 20 years of the twentieth century began the active use of calcium chloride as an accelerator, and sugar, as the moderator. Top of the use of plasticizers can be attributed to the 30s, and air-supplements – to 50-th year. Classification of concrete admixtures All additives in concrete mixtures are classified according to GOST 24211-91. Grouts are divided into four main groups: 1. Regulatory properties of concrete mixtures: – Group I plasticizers (superplasticizers), plasticizers group II (cilnoplastifitsiruyuschie), plasticizers Group III (sredneplastifitsiruyuschie), plasticizers Group IV (Slaboplastifitsiruyuschie) – stabilizing – water-retaining – improving perekachivaemost – regulating the keeping of concrete mixtures – delaying setting – setting the accelerating – porizuyuschie (for lightweight concrete): air-entraining, foaming, blowing.
2. Regulatory hardening concrete: – slow down hardening – hardening accelerating. 3. Increase the strength and (or) corrosion resistance, frost resistance of concrete and reinforced concrete, reduce the permeability of concrete: – vodoredutsiruyuschie I, II, III and IV – kolmatiruyuschie – blowing – air-entraining – enhancing the protective properties of concrete in relation to steel reinforcement (steel corrosion inhibitors). 4. Giving a concrete special properties: – antifreeze (provide curing at low temperatures) – hydrophobic I, II and III.