Ⅰ. Composition of self-leveling cement
Self-leveling cement is also called self-leveling mortar. It is a hydraulic composite material made of cement as the base material and highly compounded with other modified materials. Existing self-leveling cement mortar has a variety of formulas, but the composition is similar, mainly composed of six parts:
1. Mixed cementitious materials
There are three main types: high alumina cement, ordinary Portland cement, and a-hemihydrate gypsum/anhydrite, accounting for 30%-40%.
2. Mineral fillers
Mainly quartz sand and calcium carbonate powder, accounting for 55%-68%.
Mainly retarder – tartaric acid, coagulant accelerator – lithium carbonate and superplasticizer – water reducing agent, accounting for 0.5%.
4 Rheology Modifier
Mainly defoaming agents and stabilizers, accounting for 0.5%.
5. Enhance components
Mainly redispersible rubber powder or cellulose ether products, accounting for 1%-4%.
Add an appropriate amount of water according to the recipe requirements to make a self-leveling mortar.
Ⅱ. Self-leveling cement mortar formula list
28% Portland cement 42.5R, 10% high alumina cement CA-50, 41.11% quartz sand (70-140 mesh), 16.2% calcium carbonate (500 mesh), 1% semi-hydrated gypsum, 6% anhydrite (hard Gypsum), 1.5% latex powder AXILATTM HP8029, 0.06% cellulose ether MHPC500PF, 0.6% water reducing agent SMF10, 0.2% defoaming agent AXILATTM DF770 DD 0.18% tartaric acid 200 mesh, 0.15% lithium carbonate 800 mesh, 1% hydrated lime.
26% Portland cement 52.5R, 10% high alumina cement, 3% hydrated lime, 4% natural anhydrite, 44.21% quartz sand (0.1-0.3mm, silica sand is the best because of its good fluidity), 10 % calcium carbonate (40-100um), 0.5% superplasticizer (melamine, Peramin SMF10), 0.2% tartaric acid or citric acid, 0.1% defoaming agent P803, 0.04% lithium carbonate (<40um), 0.1% sodium carbonate, 0.05% cellulose ether (200-500mPas), 1.8% ElotexFLOWKITFL1212, 22-25% water.
Ⅲ. Performance requirements of self-leveling cement mortar
The performance requirements of self-leveling cement mortar include fluidity, slurry stability, compressive strength, etc.:
1. Fluidity: Generally, the fluidity is greater than 210~260 mm.
2. Slurry stability: Pour the mixed slurry onto a horizontal glass plate. After 20 minutes of observation, there should be no obvious bleeding, layering, segregation, bubbling, etc.
3. Compressive strength: The compressive strength of ordinary cement mortar surface is required to be above 15MPa. The compressive strength of cement concrete surface layer is above 20MPa.
4. Flexural strength: The flexural strength of industrial self-leveling cement mortar should be greater than 6Mpa.
5. Coagulation time: After ensuring that the slurry is evenly stirred, ensure that its use time is more than forty minutes. Operability is not affected.
6. Impact resistance: Self-leveling cement mortar should be able to withstand collisions caused by normal traffic of human bodies and items being carried, and the ground impact resistance should be greater than or equal to 4 Joules.
7. Bonding tensile strength to the base layer: The bonding tensile strength of cement floor self-leveling materials is usually above 0.8MPa.
Landcel is a manufacturer specializing in the production of cellulose ether products and re-dispersible polymer powder. Our cellulose ether products can be used for self-leveling additions of different grades and requirements. Welcome to consult and purchase.