Ultra-high strength sulfoaluminate cement can play a good role in cement self-leveling mortar:
1. Increase the mechanical strength of the surface;
2. Improve early strength;
3. Reduce shrinkage and control cracking;
4. Improve the surface decoration effect, and the sulfoaluminate cement has good tinting strength;
5. Improve fluidity under certain dosage.
In the ternary system of Portland cement-ultra-high-strength sulfoaluminate cement-gypsum, whether it is mainly Portland cement or ultra-high-strength sulfoaluminate cement, as long as the proportion is appropriate, it can be formulated with excellent performance. of self-leveling mortar.
In contrast, the self-leveling mortar mainly composed of Portland cement has a longer setting time, and the initial setting is generally between 70min and 120min. fluidity.
The self-leveling mortar based on ultra-high-strength sulfoaluminate cement has a short setting time, and can generally set and harden in 30-60 minutes. It is very suitable for thin-layer self-leveling and projects that require high early strength.
At the same time, in the ternary system, the ultra-high-strength sulfoaluminate cement plays a key role in reducing the dimensional change rate, and the dimensional change value can reach ±0.05%.
In the process of practical application, it was found that due to the limitation of site conditions, many ground bases have no waterproof layer, some side walls have leakage, and some projects are renovation of old houses, and the moisture content of the base is large, far exceeding the humidity requirements.
Under such circumstances, a shorter expansion stabilization period is particularly important for self-leveling mortars, and the addition of ultra-high-strength sulfoaluminate cement successfully solved this problem.
The appearance of ultra-high-strength sulfoaluminate cement is yellowish-white, and the color of the material is improved in the ternary system (especially the ultra-high-strength sulfoaluminate cement), which has a good decorative effect, especially in the preparation of colored cement self-leveling mortar, the effect is better.
Ultra-high strength sulfoaluminate cement can play a good role in non-shrinkage grouting materials:
1. Improve the early strength, and the later strength continues to grow steadily;
2. Compensate shrinkage and effectively prevent cracking;
3. Used alone, sulfoaluminate cement can be used to prepare special grouting materials with high hourly strength;
4. The grouting material can realize winter construction.
The addition of ultra-high-strength sulfoaluminate cement to the ternary system mainly composed of Portland cement can compensate for the later drying shrinkage and improve the early strength.
Using a ternary system based on ultra-high-strength sulfoaluminate cement, while ensuring high fluidity and sufficient working time, grouting materials with high hourly strength (2-hour compressive strength greater than 30MPa) can still be formulated.
In addition to being added to ordinary non-shrinkage grouting materials in the form of mineral additives, ultra-high-strength sulfoaluminate cement can also be mixed with gypsum and admixtures as a bearing grouting material for basin rubber on high-speed railway passenger lines. It is used in projects with high requirements on hourly strength.
The special grouting material prepared with ultra-high strength sulfoaluminate cement can be used for winter construction at the lowest temperature of -30℃.
Due to the micro-expansion of the material itself, after adding the plastic expansion component, the plastic state and the "double expansion" function after hardening are realized, and the highest vertical expansion rate in 3h can reach 3.5%.
Ultra-high-strength sulfoaluminate cement has stronger fast-hardening properties and can be formulated as fast-hardening tile adhesives. Adding it to the grout can compensate for shrinkage and effectively prevent alkali return.
Since C2S and C3S in Portland cement generate a large amount of Ca(OH)2 while generating hydrated C-S-H, which is an extremely deliquescent substance, it will migrate to the surface of the mortar and the air with the evaporation of water. The role of CO2 in the formation of CaCO3 and back to alkali.
After the introduction of ultra-high-strength sulfoaluminate cement, 3CaO·3Al2O3·CaSO4 produced ettringite Aft expansion crystals under the excitation of Ca(OH)2 and CaSO4 and filled the capillary cracks, preventing the way of free water seeping out, which plays a role in inhibiting alkalosis.
