The important understanding and application error of polymer cement waterproof coating

Polymer cement waterproof coating application error
polymer cement waterproof coating (JS waterproof coating), with its good physical properties, simple construction methods and can be moved on the wet grass, etc. , from the end of the last century to the beginning of this century has been rapid development and widespread application. However, in recent years, such products have a great potential for quality hidden dangers, to many construction units and management departments left a very bad impression and began to be skeptical, new products came out less than a decade ago to face with the poor quality of the elimination of products for the embarrassing situation, it is regrettable, the reasons in addition to the market low-cost competition manufacturers deliberately sacrifice quality and construction process supervision is not allowed to allow the proliferation of stealing materials, but also with this product improper application and many industry insiders have misconceptions about this product.
1, the selection of latex and the ratio of ingredients to the understanding of the
The basic principle of JS waterproof coating is to synthesize polymer latex modified with cement and quartz sand as the main composition of inormeric gel material, the formation of the coating film on the basis of basically maintaining the high strength of cement gel material, strong water resistance characteristics, as far as possible to improve its flexibility (i.e. e.g. elongation rate
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. At the same time, polymer latex also brings negative effect, that is, the decline of hardness and long-term water resistance and aging resistance, its negative effect size and the type and doping of latex used is closely related (i.e., the modified capacity of latex), the current market for JS coatings, there are two main types of latex - polyacrylate latex and polyethylene-ethylene acetate latex. The former has better ability of change than the latter, and the amount of usage to achieve the same performance is significantly less than that of the latter, and its negative effect is significantly smaller than that of the latter. But most people mistakenly think that JS paint should be the larger the amount of latex, the better, in the purchase of different manufacturers of products at the same price to compare which factory's latex consumption is large and choose. Therefore, some manufacturers or merchants in order to show that their products latex consumption is large, the purchase of latex raw materials mixed with water and then the preparation of JS paint, its product quality and the real JS paint is far from, and even more, some construction teams in low-cost contract waterproofing project After, the use of market-purchased polyvinyl acetate latex (commonly known as white latex) or polyethylene alcohol glue (commonly known as 107 glue) mixed construction, the consequences of which can not be described, seriously damaged the reputation of JS coatings. At present, the construction of a large number of JS coatings, the real use of polypropylene latex less than 10%, which is the main reason for JS coatings into the ranks of "poor" products.
2, the use of classification is not
The elongation size of JS waterproof coating is directly related to the amount of latex, but the size of latex doping directly affects the long-term water resistance of the coating, in order to solve this contradiction, the technical treatment of engineering specifications and product standards is to divide JS coating into two types, I. type is a large amount of latex, the elongation rate requires more than 200%, for intermittent immersion of the engineering parts (such as roof, exterior wall, etc.) to meet its deformation requirements. TYPE II. Type is slightly less latex dosing, as long as the elongation rate reaches 80%, to meet the deformation is small but has long-term water resistance requirements of the engineering parts (basement, toilet bath, etc.), but in many projects there is no distinction between the use, from the basement to roof are using a type, I. type or II. type, not only does not achieve the expected effect there are many quality hazards, disappointing.
3, the relationship between coating thickness and construction number
a good waterproof coating also has to have a certain coating thickness as a quality assurance, in the "roof engineering technical specifications" and "underground engineering waterproofing technical specifications", the basic thickness requirements of JS coatings 1.5 to 2.0mm. In the actual engineering design and construction monitoring often only pay attention to the number of construction but ignore the final thickness of the coating, often see some design drawings only marked "using JS waterproof paint a few coatings" but does not indicate the thickness requirements. Site management also cares only a few times about painting. To some lack of integrity of the construction team drilled a hole, the paint added water to thin, than the design requirements to apply one or two times also get the praise of field managers, at a low price contracted to the project can also earn a lot of profits, excellent performance of products can not afford such damage.
4, ignoring the importance of on-site mixing state on the performance of the coating film
JS coating is a two-component product, in fact, the product production of the last process - mixing phase, left to the site construction team to complete. I do not know, the two-group product mixing phase state is crucial to the formation of coating film performance, coupled with JS paint for powder-liquid double-parts are not as easy as other liquid-liquid two-group products mixing and mixing, although the manufacturers have instructions for the correct method of on-site mixing, but many construction team mixing process is perfunctory, some even no special mixer, the scene to find a stick manual mixing and mixing. Very few people know the judgment and mastery of "phase end", so that the final form of coating performance because of mixing and phase incomplete and greatly reduced.
5, the understanding of stretch strength error
in the product standard of JS coating film stretch strength requirements are I.type ≥1.2MPa, II.type ≥1.8MPa, many people mistakenly think that the higher the stretch strength, the better, in fact, in J In the extrusion performance test method of S coating, there is a standard maintenance 7 days after 50 degrees C heating maintenance 24h process, many paint products are in the process of thermal maintenance at 50 degrees C due to the volatile migration of plasticizers and make the extrusion strength rapid growth, indicating that these products in the exposure to the use of thermal aging performance changes quickly, life is not long. Therefore, for products with unusually high stretch strength, alertness should be raised and, if necessary, thermal aging rate testing can be done. Instead of one-sidedly arguing that the higher the stretch strength, the better.
6, randomly set the tire base position
in some engineering node details in order to avoid stress concentration to add tire base to spread the stress to reduce the coating cracking phenomenon. Therefore, the setting of the tire base position directly affects the use of the effect, should be the tire base closer to the grass-roots more can achieve the role of dispersal stress, and in fact, many projects arbitrarily set the tire base position no one asked, to set in the middle of the coating for more, some projects will be the tire base laid on the coating surface, the author found this phenomenon in a construction site after asking the construction staff why the tire base exposed on the surface? The worker replied: "It is ironic to settle the tire-based money with the issuer".
7, one-sided understanding of "can be called in the wet grass-roots construction"
JS waterproof coating compared to other waterproof coatings is characterized by the construction of wet grass, there is a humidity problem, not that any humid climate conditions or very high grass water content can be constructed, because JS paint latex is through volatile curing, excessive grass water content and too humid climatic conditions on the curing film of latex adverse, will reduce the extension rate of the coating film. At the same time, the cement in JS coating is cured by hydration, too dry grass and climatic conditions, but also against cement curing, so in the hot and dry season when the construction of the grass-roots spray some water before construction. In fact, JS coating on the construction of the temperature and humidity range or some requirements, generally is the temperature in 5 degrees C to 35 degrees C, humidity in 50% to 70% is appropriate, regardless of temperature and humidity conditions forced construction, although can also be filmed, but the coating performance is far away.
8, the misunderstanding of water-added deployment
most manufacturers in their product descriptions that the first brushing construction can be watered to dilute the paint and improve the penetration of the grass-roots to improve the bonding force of the grass-roots. Therefore, many people misunderstand that JS coatings can be freely added water, which is very harmful, JS coatings in two components than - poly ash ratio (polymer to cement ratio) and water ash ratio (water and cement ratio) is the manufacturer through a number of tests to determine, arbitrarily change one of the Ingredient ratio on the film performance of the impact is very large, the actual project arbitrarily increase the amount of powder and then casually add water to adjust the consistency of the phenomenon abounds, in fact, many projects are by using the name of JS paint to steal materials, so the application, JS coating future rest.