Concrete admixture is a new technology of concrete technology. Almost all concrete admixtures, mortar and cement paste can be improved by admixture. Due to the wide application of concrete admixtures, admixtures have been called the fifth component of concrete.

The characteristics of concrete admixtures are many varieties and small amounts, and they play an important role in the modification of concrete. Therefore, its production process, quality control, application technology and variety selection are more important than other engineering materials.

Construction mortar admixture, which has the functions of improving the mortar’s workability, water retention, adhesion, water reduction and strength improvement, can replace all the lime in the mixed mortar, save cement consumption, reduce construction costs, improve project quality , Improve construction conditions, reduce environmental pollution, transportation, ease of use and other characteristics.

According to (GB8075-87) classification, concrete admixtures can be divided into four categories according to their main functions:

Additives to improve the rheological properties of concrete mixtures: including various water reducing agents, air entraining agents and pumping agents.

Additives for adjusting concrete setting time and hardening performance: including retarder, early strength agent, quick setting agent, etc.

Additives to improve the durability of concrete: including air-entraining agents, waterproofing agents, and rust inhibitors.

Additives to improve other properties of concrete: including air-entraining agents, expansion agents, antifreeze agents, colorants, waterproofing agents and pumping agents.

According to the naming and definition of (GB8075-87) admixture, the admixture can be divided into 16 names, and their respective definitions are as follows:

Ordinary water-reducing agent: an additive that can reduce the amount of water used for mixing under the same conditions of concrete slump;

Early strength agent: an additive that accelerates the early strength development of concrete;

Retarder: an additive that prolongs the setting time of concrete;

Air-entraining agent: an admixture that can introduce a large number of evenly distributed, stable and closed tiny bubbles in the process of mixing concrete;

High-efficiency water-reducing agent: an additive that can greatly reduce the water consumption of the mixture under the same conditions of concrete collapse;

Early strength water reducing agent: a water reducing agent with both early strength and water reducing function;

Retarding and water-reducing agent: water-reducing agent with both functions of retarding and water-reducing;

Air-entraining water-reducing agent: an additive with both air-entraining and water-reducing functions;

Waterproofing agent: an additive that can reduce the permeability of concrete under hydrostatic pressure;

Rust inhibitor: an additive that can inhibit or reduce the corrosion of steel bars or other embedded metals in concrete;

Air-entraining agent: an admixture that releases gas due to a chemical reaction in the process of concrete preparation, which can make the concrete form a large number of pores;

Expansion agent: an additive that can cause a certain expansion of the concrete volume;

Antifreeze: an admixture that can harden the concrete at negative temperature and reach sufficient antifreeze strength within the specified time;

Colorant: Additive that can prepare concrete with stable color;

Quick-setting agent: an admixture that can quickly harden concrete;

Pumping agent: an additive that can improve the pumping performance of concrete mixtures.