Characteristics of High-efficiency CSA Expansive Agent
Features by using High-efficiency CSA Expansive Agent
Chemical Analysis
Main constituents (%)
|
SiO2 |
Al2O3 |
Fe2O3 |
CaO |
MgO |
SO3 |
f-CaO |
R2O |
Cl- |
Ig-loss |
Usual range |
4~7 |
8~12 |
< 1.5 |
50~55 |
2~4 |
22~25 |
10~15 |
< 0.3 |
< 0.05 |
< 5 |
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:
Dosage in OPC (%) |
Restrained-expansion rate (%) |
|
Curing 7d in water |
Curing 7d in water then 21d in air |
|
TypeⅠ,7 |
0.050-0.080 |
≥ 0 |
TypeⅡ,7 |
0.025-0.045 |
≥ -0.015 |
TypeⅡ,10 |
0.055-0.080 |
≥ 0 |
The effect of High-efficiency CSA Expansive Agent dosage on strength of cement mortar:
Dosage(%) |
Compressive Strength(MPa) |
|
7d |
28d |
|
7 |
> 40 |
> 54.0 |
0 |
37.0 |
56.5 |
Longitudinal change of mortar:
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.