Guangdong Crown Paint Company Limited

Knowledge about cement-based self-leveling mortar

As cement-based self-leveling is more and more popular, and everyone is more and more interested in self-leveling , what exactly is cement-based self - leveling ? Let us introduce what is cement-based self-leveling.


1. What is cement-based self-leveling, can it be leveled on the ground like water?


Cement-based self - leveling mortar is a dry powder product formulated by using special cement, selected aggregates, dry powder resin and various modifications. It is mixed with water to form a fluid slurry with excellent fluidity. Can lay down, can quickly unfold automatically. Instead of flowing to a long place like water, it only has a certain degree of flow (about 130mm) and flow direction (it depends on the construction temperature, about 3-5 minutes of construction time). It can only flow from high to low), after a certain period of time, it will stop flowing and begin to solidify!


Cement-based self-leveling ground is an ideal base for laying flooring materials such as composite flooring, PVC flooring, and epoxy resin. It is more widely used for maintenance of various old workshops. It has high flatness, easy and fast construction, and bonding to the basement. Strong, no irritating odor, environmental protection and other characteristics.

2. Everyone often thinks that the floor that has been self- leveled by cement base should be a horizontal floor. Is this true?


In cement-based self - leveling construction, special attention should be paid to the difference between smooth ground and super-flat ground. The so-called smooth ground refers to the ground after construction. Although the whole is flat, the whole ground is not necessarily horizontal. some height direction, Junpei down; refers to the ultra-flat surface on the ground is the same ground a horizontal plane, ultra-flat surface construction is very complex, requiring point determined level, then the construction according to a horizontal point.


Generally encountered are smooth ground, and ultra-flat ground generally has such high requirements only in very demanding laboratories or precision processing workshops!


3Before the cement-based self - leveling construction , how to carry out site surveys and precautions?


This is a problem that is often overlooked, and it is difficult to make a correct and economical construction plan without a thorough and detailed survey of the site! When surveying, please use a pull tester and a 2-meter-long recliner and wedge feeler. The inspection should pay attention to the following aspects:

Ground strength-Use a pull tester to test the strength of the concrete surface at the grassroots level. Only grounds exceeding 1.0Mpa are eligible for construction. If the above requirements are not met, select a more severe area for reinforcement testing. Reinforcement treatment is required. After it is completely cured, perform a pull test again. If the strength requirements have not been met, then reinforcement is required.


Whether there is sand on the ground-There are two types of sand on the ground . The first case is sand caused by the bleeding of the cushion concrete . This situation is just that the surface has no strength. Mechanical polishing is used to remove the surface scum. Then carry out the cement-based self - leveling construction; the second case: the surface is sanded due to the insufficient strength of the cushion concrete. The solution is the same as the above situation, and it needs to be reinforced. After the reinforcement is completed, a pull test is performed. Yes , the cement-based self - leveling construction is implemented , and those who are not qualified cannot continue construction!

The flatness of the ground and the general direction of the fallUse a 2 meter long ruler to detect the ground . Select a measurement point of no less than 5 in a range of 100 square meters, and select the 3 lowest points in each measurement point. , Use the 15 lowest points to calculate the average value, determine the thickness of the construction; determine the level of the ground level, and mark on the wall, choose construction from the high point to the low point during construction. Delineate a particularly low place, and carry out local construction first. The construction process is the same as the normal construction process. Wait 24 hours before performing the overall construction!


4How to calculate the construction thickness and material usage, and calculate the cement-based self - leveling quotation in order?


Through careful survey of the site, we can get the basic treatment method, and then determine the cost of basic treatment; according to the standard dosage of 1.7kg / mm / m2, multiply the thickness by construction to get the material usage per square meter. It is recommended that construction companies order more than 3% to 5% of the total preparation amount when ordering materials to prevent deviations and unforeseen situations at the survey site. Cement-based self - leveling quotation composition = base treatment cost + interface agent + material Consumption + construction fee + management fee + engineering tax.


In addition, during cement-based self - leveling construction , the moisture content of the concrete base is relatively high. Can it be constructed?

The high moisture content of the concrete base has no effect on the construction of cement-based self - leveling . Because the cement-based self - leveling construction is self-leveling mortar added with water, it is paved on the concrete foundation after mixing, and the water-based interface agent is also applied before paving. Therefore, the water content of the base layer is high, and there is no effect on the cement-based self - leveling construction. Affected. However, there must be no clear water on the surface of the base layer, and the deformation of the concrete has stabilized.


5When the sand on the ground is serious , the orange peel phenomenon appears after the cement-based self - leveling treatment . Why?


The main reason is that when the sand from the ground is serious , it will affect the leveling of self-leveling . It is recommended to increase the construction thickness, at least 4mm or more, which can be slowed down to eliminate this phenomenon.


In addition, grease easily penetrates into the capillary pores of cement-based self - leveling , and oil stains appear. However, the main components of cement-based self - leveling materials are inorganic materials such as cement and quartz sand, which will not react with the glue sticking to PVC .


6. Can self-leveling stains be removed in daily life? If not, what are the economical and convenient ways to prevent them?


It is not easy to remove stains from self-leveling surfaces. If the self-leveling squeegee aqueous twice a sealing wax to the surface, capable of closing self-leveling surface pores, self-leveling rear surface off the stains easier to remove the self-leveling in the construction process, an aluminum alloy splashed or kick moldings How to remove the stain on the surface without scratching the surface of the object? Since self-leveling has good bonding strength, it is not easy to remove on the aluminum alloy gradually during construction . Therefore, it is suggested that protection work should be done before self-leveling construction , and surrounding facilities should be covered to prevent removal after pollution.


7. Does dry powder resin in self-leveling cause harm to human body?


Self-leveling dry powder resin is water-based redispersible rubber powder, which will not cause harm to human body.


8. What to do if there are cracks in the grassroots?


For large cracks in the base layer, they should be cut into V -shaped grooves, and then cleaned up. Use a self-leveling dry powder with a small amount of water and stir to achieve the consistency of the plaster mortar. Fill the cracks and smooth them.


9. In the process of self-leveling construction , if the sand on the ground is serious , what can be done to prevent air holes on the ground after construction?


First sand the ground with a sander to remove the loose layer on the surface. Then clean the ground, use a vacuum cleaner to remove the dust, apply the interface agent twice, and wait for the interface agent to dry completely before performing self-leveling construction.


10Self-leveling construction will produce color differences (ie watermarks). How long does it take for such a watermark to disappear?


The self-leveling color difference is formed due to the inconsistent flow control of self-leveling during construction . If the amount of water added is too large, it will leak water on the surface and form a color difference after hardening. Under normal use conditions, the color difference will become lighter with use.


11. Air bubbles on the surface after construction?


The interfacial agent is not uniformly applied, so the interfacial agent should be applied twice.


12. How thick can self-levelling be?


The self-leveling thickness of cement generally cannot exceed 25px.


13. Inconsistent fluidity per barrel?


Whether the amount of water is strictly controlled. Whether the stirring time is consistent, the stirring time is long, sufficient, and the fluidity is large.


14. What is the best curing method for cement self-leveling ?


Doors and windows should be closed during and after construction and maintained for 2-3 days.


15. Low surface strength and lighter color?


The main reasons include: too much water is added to cause bleeding ; the temperature of the construction environment is too low, and the hydration reaction is slow


16. Is the cement self-leveling construction fast?


After the grass-roots treatment is completed, the cement self-leveling construction speed is very fast, mechanical mixing of 6 people / group, each group can be applied for 2,000 square meters per day, manual mixing, 8 people / group, each group can be applied for approximately 800 square meters per day. To ensure that the construction process is not power, not without water.


17. What kind of floor is suitable for cement self-leveling?


As long as the strength of the base course is not very poor, or the strength of 1.0Mpa can be reached after reinforcement, cement self-leveling construction can be performed . If the height difference is large or the slope of the base course is obvious, then a sufficient thickness of cement self-leveling is required. For leveling, more than 8mm, it is recommended to divide the construction!


18. What should I do if the sand- laden ground is self-leveling ?


First of all, it is necessary to perform surface strengthening treatment on the sandy ground, and then carry out the subsequent work of cement self-leveling after painting the ground with epoxy .