Lignosulfonate used as high-efficiency concrete admixture

Practitioners keep paying heed to the improvement of concrete effects by adding admixtures into concrete.

Among all concrete admixtures, lignosulfonate is used as a water reducer to effectively change, improve concrete properties.

Lignosulfonate is also a cement retarder and can also have some very beneficial effects in concrete.

Effects of adding lignosulfonate into concrete:

As water reducer, a proper amount of lignosulfonate is added into concrete.

During concrete mixing, the water reducer is absorbed to cement particles to produce same electric charges among the particles. The electric charges repel each other, shaping dispersive cement particles as a result.

Influenced by the water reducer, the cement particles in concrete get disperse, reducing the formation of cement floccules in concrete and reducing the amount of water for mixing.

In concrete, the flowability of cement paste keeps increasing with the increase of free water.

Impacts on concrete:

1、 Strength improvement

By adding a proper amount of lignosulfonate, as water reducer, into concrete, if the concrete workability remains unchanged, the amount of water will be reduced by 5% - 25% to improve concrete strength.

Comparison of concrete strength to reference concrete:

The 3-day strength is 15% - 20% higher, the 7-day strength is 20% - 30% higher, and the 28-day strength is 15% - 20% higher.

In the long run, concrete strength can be remarkably improved by adding water reducer into it.

2、 Easier construction

If the water cement ratio remains unchanged, by adding moderate lignosulfonate into concrete as water reducer, the slump increases by 10 cm – 20 cm, meeting the concrete requirements in large formwork construction and lift slab construction.

3、Less water

If the concrete strength remains unchanged, by adding moderate lignosulfonate into concrete as water reducer, the amount of water for concrete in the same condition will be reduced by 5% - 20%.

4、Enhanced flowability and workability

Concrete flowability and workability are enhanced remarkably.

5、 Less cement, lower cost

If the concrete slump is the same and the strength is the same as that of reference concrete, 8% - 10% cement can be saved.

If one ton of lignosulfonate is used as water reducer, 30 to 40 tons of cement can be saved.

6、Less bubbles

The water dispersion ability of concrete can be increased by adding lignosulfonate to reduce bubbles in concrete.

7、 Non-corrosive

Used as a concrete additive, lignosulfonate is non-corrosive to concrete aggregates and rebar.

8、 Extending concrete setting time

 Lignosulfonates can be used as concrete retarder.

In normal conditions, the setting time of concrete with lignosulfonate as an additive is extended for over 3 hours compared to that of reference concrete, and the hydration heat peak value is extended for more than 5 hours.

The feature is in favor of concrete construction and transport in summer and the construction of mass concrete.

9、Used for preparing high-strength, ultrahigh-strength concrete

Used as water reducer, lignin can be a main raw material for producing high-performance cement. By adding water reducer of various properties into concrete, extended high-strength concrete, high-strength concrete, and ultrahigh-strength concrete can be produced.

Additive amount:

General addition (0.2%-0.3%); it is easy, flexible, and economical to produce high-performance concrete by using water reducer.

By adding moderate water reducer as an additive into concrete, the operation can not only improve concrete properties but also save cement, improve quality and economic benefits for lower costs and higher efficiency.

Concrete water reducers with good effects and low costs have been popular with users at home and abroad.