Concrete water reducer is widely used in construction. They are usually divided into lignosulfonate water-reducing agents, naphthalene-based superplasticizers, melamine-based superplasticizers, sulfamate-based superplasticizers, fats family superplasticizers, polycarboxylate superplasticizer.
The role of concrete water reducer
The water-reducing agent refers to an admixture that can reduce the mixing water consumption and increase the strength of concrete under the conditions of constant workability and cement consumption, or save cement consumption under the conditions of constant workability and strength.
The use of concrete water reducer can save cement, reduce costs, shorten the construction period, improve the construction of concrete, and increase the quality and service life of buildings. It is of great significance in energy saving, environmental protection, engineering economy, labor protection, etc. Its uses are mainly reflected in:
Without changing the ratio of various raw materials (except cement) and concrete strength, the amount of cement can be reduced. Adding a concrete water reducing agent of 0.2%-0.5% of the cement mass can save more than 15-30% of the cement;
Without changing the ratio of various raw materials (except water) and the slump of concrete, reducing the amount of water can greatly increase the strength of concrete. The early strength and later strength are respectively above 60% and 20% higher than those of concrete without water reducing agent. Through water reduction, high-strength concrete with C100 mark can be poured;
Without changing the ratio of various raw materials, the rheology and plasticity of concrete can be greatly improved, so that concrete construction can be carried out by gravity, pumping, without vibration, etc., which can increase the construction speed and reduce the construction energy consumption;
Adding concrete superplasticizer can increase the life of the concrete by more than double, even if the normal service life of the building is more than doubled;
Reduce the shrinkage of concrete solidification, prevent cracks in concrete components, improve frost resistance, and benefit winter construction.
The development of international water-reducing agents has gone through three stages: the first-generation general water-reducing agent stage represented by wood calcium, the second-generation high-efficiency water-reducing agent mainly represented by naphthalene series (mainly naphthalene sulfonate series, Sulfonated melamine series, aliphatic series, sulfamate series, etc.) stage and the third generation high-performance water reducing agent stage represented by polycarboxylic acid series. At present, the domestic water-reducing agent market is dominated by second-generation water-reducing agents, with three-generation water-reducing agents coexisting, and the market share of polycarboxylic acid-based water-reducing agents is increasing year by year.