Concrete admixture specification and selection general requirements

What are the Concrete Admixtures?

Concrete admixtures are divided into four categories according to their main functions:

(1) Additives for improving the rheological properties of concrete mixes, including various water-reducing agents, air-entraining agents, and pumping agents;

(2) Additives for adjusting the setting time and hardening properties of concrete, including retarder, early strength agent, and accelerator;

(3) Additives for improving the durability of concrete, including air-entraining agents, water repellents, and rust inhibitors;

(4) Admixtures for improving other properties of concrete, including air-entraining agents, swelling agents, antifreeze agents, colorants, water repellents, and pumping agents.

Ordinary water-reducing agent: Under the condition that the concrete slump is basically the same, the mixing water consumption can be reduced.

Early strength agent: Accelerate the early strength development of concrete.

Retarder: Extend the concrete setting time.

Air-entraining agent: It can introduce a large number of evenly distributed, stable and closed micro-bubbles in the process of mixing concrete.

High-efficiency water-reducing agent: Under the condition that concrete slump is basically the same, it can greatly reduce the mixing water consumption.

Early strength water reducer: both early strength and water reduction function.

Retarder Water Reducing Agent: retarding and reducing water function.

Air-entraining water reducing agent: bleed air and water reducing function.

Anti-corrosion agents: reduce the water permeability of concrete under hydrostatic pressure.

Rust inhibitors: Suppress or reduce corrosion of steel or other embedded metals in concrete.

Air-entraining agent: Due to a chemical reaction during the preparation of concrete, gas is released, and a large number of pores are formed in the concrete.

Expansion agent: The volume of concrete expands.

Antifreeze: Hardens the concrete at negative temperatures and achieves adequate antifreeze and strength within the prescribed time.

Colorant: Prepare concrete with a stable color.

Accelerating agent: Make concrete harden and harden.

Pumping agent: Improve the pumping performance of concrete mix.

In the prescribed amount, the admixture basically has little side effects.

Concrete admixture

(1) It can reduce the water consumption of concrete. Or it can increase the fluidity of concrete without increasing the water consumption.

(2) The setting time of the concrete can be adjusted.

(3) Reduce bleeding and segregation. Improve workability and water washability.

(4) It can reduce slump loss and increase the pumpability of pumped concrete.

(5) Shrinkage can be reduced. Adding bulking agent can also compensate for shrinkage.

(6) retard the initial heat of hydration of concrete, reduce the temperature rise rate of mass concrete, and reduce the occurrence of cracks.

(7) Improve the early strength of concrete. Prevent freezing at negative temperatures.

(8) Improve strength, increase frost resistance, impermeability, abrasion resistance, and corrosion resistance.

(9) Control alkali-aggregate reaction, prevent corrosion of steel bars and reduce diffusion of chloride ions.

(10) Concrete made of other special properties.

(11) Reduce the viscosity coefficient of concrete, etc.

Concrete admixture price

Water reducer is divided into powder and liquid two kinds of liquid cheaper about 2000~3000 a ton

Air-entrained pastes have a high solid content with a large cover price of more than 10,000 yuan a ton

Note: This price is for reference only! Due to geographical differences, of course, the price will be different. For more details on the prices, please refer to the local distributors!

Concrete Admixture Specifications

Concrete admixtures should not be used in excessive amounts, nor too little, and need to correspond to the amount of cementitious material. When adding the admixture, it is necessary to refer to the production dose recommended by the production unit on the product packaging, and carefully read the precautions for use, the necessary conditions for the use of admixtures, and so on. If the admixture contains some special chemical elements, such as chloride ions, sulfate ions, it needs to be reasonably added according to some regulations, and it cannot be used arbitrarily.

Editor's summary: Some concrete admixtures are powdery. The preservation of this admixture is a very important issue. If the preservation is not good, it is likely that the admixture will get wet so that it will be agglomeration and difficult to use. The waste, so the preservation of the admixture is also a problem that requires extra attention. If the admixture is a liquid, it needs to be placed in a cool and dry place, because if it receives the influence of some external conditions such as sun exposure, water intake, etc. , Its performance is likely to be affected.