MOQ | 20 tons |
Port | Tianjin |
Packaging | 25 kg bag, Jumbo bag |
Lead Time | 2 weeks |
Color | Light gray | Expansion | Stable expansion additve for concrete |
Shrinkage reducing | Yes |
General characteristics
High-efficiency CSA expansive agent is obtained by blending suitable natural anhydrite with a specially manufactured clinker which consists essentially of calcium sulphoaluminate and CaO.
CSA expansive agent is always mixed with ordinary cement. When mixed in the proper proportions with ordinary cement and hydrated, cement mortar or concrete expands during the early stages of hydration. This expansion, when restrained, makes it possible to minimize drying shrinkage. Moreover, when the ratio of shrinkage reducing admixture to ordinary cement is increased its high expansion qualities make it ideal for use in prestressed concrete.
High-efficiency shrinkage reducing admixture is being used in all sections of the construction fields and by a wide variety of concrete products manufacturers.
Properties
Characteristics of High-efficiency CSA Expansive Agent
1. Low alkalinity. High-efficiency CSA Expansive Agent has a very low alkali content (R2O <0.3%) which is beneficial to avoid AAR in concrete.
2. Short stable stage of expansion. The stable stage of expansion is not more than 14 days, thus the ultimate strength of concrete is not affected.
3. Low dosage and high expansion capacity. The normal dosage of High-efficiency CSA Expansive Agent is 6~8% by the weight of ordinary cement, which is lower compared with other expansive additives such as UEA and CEA (their dosages are about 10~12% by the weight of cement) in the market.
Features by using High-efficiency CSA Expansive Agent
Prevents cracking due to drying shrinkage and hydration heats.
Increases the water tightness of concrete and thus is useful for waterproofing buildings.
Enables the manufacture of high strength concrete products through chemical prestressing.
Chemical Analysis
Main constituents (%)
CSA Expansive agent Type I
Item | SiO2 | Al2O3 | Fe2O3 | CaO | MgO | SO3 | TiO2 | Cl- | Lg-loss |
Usual Range | 5.5-7 | 5-7 | 1-2 | 50-52 | 2-4 | 24-27 | <1 | <0.05 | 6-8 |
CSA Expansive agent type II
Item | SiO2 | Al2O3 | Fe2O3 | CaO | MgO | SO3 | TiO2 | Cl- | Lg-loss |
Usual Range | 3-5 | 8-10 | 0.5-1.5 | 52-55 | 2-4 | 25-28 | <1 | <0.05 | 4-6 |
CSA Expansive agent type III
Item | SiO2 | Al2O3 | Fe2O3 | CaO | MgO | SO3 | TiO2 | Cl- | Lg-loss |
Usual Range | 3-4 | 9-11 | 0.5-1.5 | 56-58 | 2-4 | 22-24 | <1 | <0.05 | 3-4 |
Mineral Composition: CaO, CaSO4, 3CaO·3Al2O3·CaSO4.
Specific Surface Area: 200~400 m2/kg.
Specific Gravity: 2.8~3.0.
Physical Properties
The restrained expansion rate tested under standard condition:
CSA Expansive agent type I
Dosage in OPC (%) | Restrained expansion rate (%) | ||||
Type I, 7% | curing 1 day in water | curing 3 days in water | curing 7 days in water | curing 28 days in water | wet air curing 21 days |
Usual Range | 0.01-0.015 | 0.02 | 0.040 | 0.05 | > -0.02 |
Standard requirement | 0.035 | > -0.02 |
CSA Expansive agent type II
Dosage in OPC (%) | Restrained expansion rate (%) | ||||
Type II, 7% | curing 1 day in water | curing 3 days in water | curing 7 days in water | curing 28 days in water | wet air curing 21 days |
Usual Range | 0.15 | 0.025 | 0.060 | 0.07 | 0 |
Standard requirement | 0.050 | ≥ -0.01 |
CSA Expansive agent type III
Dosage in OPC (%) | Restrained expansion rate (%) | ||||
Type III, 7% | curing 1 day in water | curing 3 days in water | curing 7 days in water | curing 28 days in water | wet air curing 21 days |
Usual Range | 0.03 | 0.060 | 0.080 | 0.10 | 0.025 |
Standard requirement | ≥0.075 | ≥ 0.020 |
Dosage(%) | Compressive Strength (Mpa) | |
7 days | 28 days | |
7% | > 40.0 | > 54.0 |
Standard requirement | > 20.0 | > 40.0 |
Application Method
1. Dosage
High-efficiency csa expansive agent is used as a part of cement, its proportion to ordinary Portland
cement depends upon the intended use and the degree of restraint. The proportion of
high-efficiency csa expansive agent to ordinary cement generally used in China is about 6~8%.
2 .Mixing
High-efficiency csa expansive agent and ordinary cement must be thoroughly and uniformly mixed
in a mechanical mixer with aggregate and water for a slightly longer time than normal concrete.
3. Curing
To ensure the proper development of the ettringite needle crystals which are important in
preventing shrinkage cracks which occur during drying period, it is recommended that water be
sprayed or membrane curing onto the concrete surface for curing at least 14 days after the
concrete is cast.
Storage
High-efficiency csa expansive agent is more sensitive to water and moisture than other
cementitious material and is therefore packed in completely waterproof bags and should always
be kept and stored in a dry place.
No. 174 West Zhaoshang Road, Leizhuang, Luanzhou, Tangshan, Hebei, China