Self-leveling cement has a wide range of applications in building construction, and its advantages and disadvantages directly affect the construction experience, construction effect and the reliability of subsequent processes. In this paper, we will evaluate the advantages and disadvantages of self-leveling cement in terms of its jointing time, flow speed and consistency, water addition, water-cement ratio, suitable temperature for construction and low-temperature performance, and the amount of sanding powder.
Self-leveling hewing time
Self-leveling cement in the construction process, usually need more than one package of cement continuous construction. Therefore, the jointing time becomes an important factor affecting the construction experience and the overall effect. Cropping time is the time interval between two packages of self-leveling cement that can be seamlessly joined to form a smooth surface after construction. If the hewing time is too short, it is easy to form obvious joints or height differences at the interface, affecting the flatness and aesthetics after construction. Especially in large area construction, longer hewing time helps to improve the construction effect.
Self-leveling flow rate and consistency
After the flow of self-leveling cement meets the requirements, the consistency and flow rate are critical to the craftsman’s construction experience. Flow rate and consistency affect the feel of the self-leveling cement as it is spread, and some tradesmen will even adjust the amount of water they add based on the consistency of the self-leveling. Ideally, self-leveling cements should have the right flow rate and consistency to allow for easy application and guaranteed results.
The amount of water added to self-leveling and the water-cement ratio
The water-cement ratio of self-leveling cement is usually between 22% and 28%, and very few products can reach 32%. The size of the water-cement ratio directly affects the flow and strength of self-leveling. The larger the water-cement ratio, the higher the flow of self-leveling, the better the construction experience, but it is easy to lead to a decline in compactness, which in turn affects the compressive and flexural strength and bonding properties. On the contrary, the smaller the water-cement ratio, the higher the density and strength of self-leveling, but the construction experience may deteriorate. Therefore, the appropriate water-cement ratio (generally about 24%) is crucial for the comprehensive performance of self-leveling cement.
Suitable temperature for self-leveling construction and low temperature performance
The suitable temperature for self-leveling cement is 15℃-25℃. Higher temperatures will shorten the joining time, while temperatures below 10°C will affect the strength of the cement, leading to sanding and insufficient strength. However, some high-strength self-leveling cements can be applied at low temperatures of around 5°C. Although there is some loss of strength, it is generally within acceptable limits. Low-temperature performance is one of the most important indicators to test the performance of self-leveling cements.
The amount of sanding powder of self-leveling cement
After the construction of self-leveling cement is completed, the surface needs to be sanded to remove the floating slurry. The amount of sanding is related to the compressive and flexural strength and flexibility of the self-leveling cement. The higher the flexibility (i.e., the smaller the ratio of compressive strength to flexural strength), the lower the amount of sanding powder. Usually, self-leveling cements with a compression-folding ratio of less than three have good sanding performance and less powdering, while self-leveling cements with a compression-folding ratio of more than five have a larger amount of powdering. Therefore, the evaluation of self-leveling cement should not only rely on the compressive and flexural strength, but also consider its flexibility.
Conclusion
To summarize, the evaluation of the advantages and disadvantages of self-leveling cement needs to comprehensively consider a number of factors, such as joining time, flow speed and consistency, water addition and water-cement ratio, suitable temperature for construction and low-temperature performance, and the amount of sanding powder. High-quality self-leveling cement should have appropriate jointing time and flow performance, reasonable water-cement ratio, as well as good low-temperature performance and sanding performance, in order to ensure the reliability of the construction effect and subsequent processes.
