Epoxy floor blisters occur on the first floor or basement, sometimes on the second floor or above. Epoxy floor blisters are usually found shortly after construction. Some epoxy pavements in the morning have blisters in the afternoon. The blister grows from small to large, and it develops to a certain extent and then stops. The higher the temperature, the easier the blisters will occur and the faster the rate of development. Blisters vary in shape and vary in size. Some blisters are more than 1m in diameter and 20~50mm in height.
There is no obvious relationship between the generation of blisters and the construction area. The same area is serious, some are lighter and some are intact. The same group of operations, the same material construction of the epoxy floor, some blisters, some intact, indicating that blisters are caused by a variety of factors.
The reason for blisters is a problem that everyone cares about. When the blisters are cut, the bubbles contain water or yellowish liquid, the epoxy surface layer is separated from the base layer, and the cement adhered to the base layer is drawn into a peak. See Figure 1-1; according to the "physical" explanation, in the closed container containing liquid, the liquid evaporates to form the relationship between the temperature and pressure of the three curves in saturation, as shown in Figure 1-2.
In a closed container, the pressure of saturated water vapor rises with increasing temperature. When the temperature is 20.C, the pressure inside the drum is 0.01 MPa; and when the temperature is between 70 and 80 °C It rises linearly to 0.1MPa; in many areas, the extreme radiant heat of the ground in hot summer days can reach 70.C. At such high temperature, the epoxy adhesive has softened and weakened, so the shape is the same. Like the air, the epoxy layer is bulged in a large bag, and the glue is pulled into a honeycomb shape; some of the epoxy layer and the ground portion without blisters are not firmly adhered, and the contact portion is carefully observed, and it is found that it is impossible to The part that is cured is because the epoxy has moisture and cannot be cured; so where does the moisture come from? There are mainly the following sources of water:
1. The base layer, such as cement mortar leveling layer, has a maximum moisture content of about 12%, and the maximum water content of the base layer is larger than the leveling layer.
2. Dehydration in other ingredients in the epoxy is endless.
3. Epoxy and base layer construction does not combine well to leave voids and the chemical activity of the epoxy itself, not completely cured or in the presence of residues or gases that are not fully cured by moisture.
4. Moisture gas infiltrated underground in the basement.
From the above four aspects, the moisture of the base layer is the main one, and the absolute dry base layer is not. The water content does not determine whether blisters will be formed on the ground. Part of the water and epoxy residues in the base layer are encapsulated in the epoxy and the base layer to form bubbles of different sizes. Since the epoxy layer itself is impervious to water, water The gas cannot be discharged, leaving a blistering root seedling. Therefore, the bubbles are generated on the plane, mostly between the base layer and the epoxy layer; the moisture in the base layer is difficult to avoid, which is an important factor causing foaming of the epoxy layer.
As the temperature of the day and night and the seasons are constantly changing, or gradually increasing, or gradually decreasing. The water vapor in the bag is condensed into small water droplets, and the pressure is also reduced. Because the epoxy layer which is bulged has a certain strength, the bulge cannot be restored to the original state, and a negative pressure is generated in the bulge, so that the base layer contains moisture. Moisture inhalation increases the amount of water produced in the bag. When the temperature rises the next day, as the moisture that can be evaporated in the bag increases, more pressure is generated, and the volume of the bulge is enlarged. From the base of the bulged bulge, some small white spots are found in the peak of the bulge, that is, The water channel connected to the base layer. People call this developed drum kit a "live pack." When the bulge bag develops to a certain size, because the base layer gradually dries, the "water source" is broken, and the bag is large and flat, which reduces the upward tearing force. Some epoxy layers at the bulge are steamed under high temperature. As the temperature rises and falls, the tensile force on the epoxy layer is large and small, causing fatigue and aging of the epoxy layer. Then, the epoxy layer of some bulges is destroyed by the external force.
Directly destroys the aesthetics of the epoxy layer, the sealing performance and durability of the clean room. Measures must be taken to prevent the generation of blisters in light of the actual conditions of the project.
1. Solve the generation of blisters in the epoxy layer, and mainly solve the "three fears" in the construction of epoxy flooring (1) fear of water; (2) fear of drying; (3) fear of dust.
2. Take measures to prevent blisters:
(1.) Make a waterproof layer on the base layer to prevent the water vapor from seeping upward. The moisture content in the base layer or the waterproof layer is within 8%, and the base layer or waterproof layer has a compressive strength greater than 20 MPa for epoxy construction.
(2.) Improve the adhesion of the epoxy layer to the base layer or the waterproof layer, and overcome the expansion force at the beginning of the blisters to avoid the occurrence of blisters.
(3.) In the construction of epoxy layer, the base coat should be made of good quality materials. First, let a part of the epoxy penetrate into the base layer or the waterproof layer to form a whole upper and lower. Second, it is to improve the adhesion and after curing. Keep little residual material or chemical gas.
(4.) Avoid sunlight exposure after epoxy construction, and reduce the temperature difference between the surface of the epoxy layer and the inside.
(5.) Construction on the base or waterproof layer must be cleaned up. There is no gap between the epoxy layer and the base layer or waterproof after construction.
(6.) In general, the waterproof material must be selected, with the following points: 1) impermeability and impermeability; 2) compressive strength, strength greater than 20 MPa; 3) superior adhesion to the ground; 4) and The epoxy resin is easily bonded to form a whole. The waterproof layer shall not be used within 3 days after the completion of construction to protect the finished product.
Solution:
Epoxy waterproof floor coating is the top epoxy waterproof floor coating in China. It can be directly applied to the wet cement floor on the first floor of wet cement, terrazzo floor and damp concrete floor which is not in the curing period. It can reach the upper epoxy. The combination is tight, and it has the advantages of heavy pressure resistance, no foaming, no delamination. Ensure that the epoxy floor construction on the first floor can not be blistered, and the adhesion to the substrate is good, ≥0.3kg per square meter.
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