some problems in the application of polycarboxylate superplasticizerii
Compatibility of polycarboxylate superplasticizer with other admixtures.
Beijing Dongke United Technologies Co.,Ltd.
It is suitable for prefabricated and cast-in-place concrete, reinforced concrete and prestressed concrete in the construction of high-speed railways, passenger lines, industrial and civil buildings, roads, bridges, ports, airports, etc.
It is especially suitable for projects with long construction time and high requirements for concrete slump, such as nuclear power projects.
In many concrete projects, traditional high-efficiency concretes such as naphthalene series are more and more unable to meet engineering needs due to the limitations of technical performance. A new generation of water-reducing agent, polycarboxylate water-reducing agent, which has attracted much attention at home and abroad, has a super-dispersed type because it has truly designed an effective molecular structure according to the mechanism of action of dispersed cement, which can prevent the loss of concrete slump without causing It has obvious retardation, high plasticizing effect at low dosage, good fluidity retention, large degree of freedom for cement to adapt to wide molecular structure, many synthesis technologies, and great room for high performance, which has a significant effect on concrete reinforcement.
It can reduce the shrinkage of concrete, the content of harmful substances is extremely low and other technical performance characteristics, endow the concrete with excellent construction workability, good strength development, excellent durability, polycarboxylate high-performance water reducer has good comprehensive technical performance Advantages and environmental protection characteristics, in line with the needs of modern concrete engineering.
Therefore, polycarboxylate water reducers are gradually becoming the preferred admixture for the formulation of high-performance concrete. According to reports, the usage of polycarboxylate water reducers in Japan has accounted for more than 80% of all high-performance admixture products, and North America and Europe also accounted for more than 50%. In my country, polycarboxylate water reducers have been successfully applied only in the Three Gorges Dam, Sutong Bridge, Tianwan Nuclear Power Station, Beijing-Shanghai high-speed railway and other large-scale national water conservancy, bridge, nuclear power, and railway projects, and have achieved remarkable results.
At the same time, polycarboxylate water reducer also has some problems:
Strong temperature sensitivity, the same kind of polycarboxylate water reducer is constructed in different seasons, and the slump retention properties of concrete are quite different;
There are few functional products, and it is difficult to meet the requirements of ultra-high and ultra-long-distance concrete pumping, negative temperature construction, preparation of ultra-early strength concrete, and high durability of concrete;
High viscosity, in the preparation of high admixture and low water-to-binder ratio concrete, the viscosity of concrete is high, which is not conducive to construction;
Strong sensitivity to the mud content of sand aggregate;
It is also poorly adapted to machine-made sand, and the dosage is sensitive to affect construction.
Polycarboxylate water reducers cannot be mixed with naphthalene-based water reducers. When using polycarboxylate water reducers, the mixers and mixer trucks that have used naphthalene-based water reducers must be rinsed clean, otherwise the reduction may be lost. water effect.
When using polycarboxylate water reducer, it can be directly added in the form of stock solution, or it can be formulated into a solution of a certain concentration, and the amount of water brought in by HK-1 polycarboxylate water reducer itself is deducted.
Due to the high water reduction rate of concrete mixed with polycarboxylate water reducer, the slump is highly sensitive to water consumption, and the water consumption must be strictly controlled during use.
Polycarboxylate water reducers have good adaptability with most cements, but for individual cements, the water reduction rate may be low and the slump loss may be too large. In addition, the fineness and storage time of cement may also affect the use effect of polycarboxylate water reducer. At this time, it is recommended to solve the problem by appropriately increasing the dosage or compounding other retarding components. Or please contact us, we will solve it for you in time.
After adding polycarboxylate water reducer, the air content of concrete increases (usually 2% to 5%), which is beneficial to improve the workability and durability of concrete. For special requirements, please contact us, we will solve it for you in time.
Due to the small dosage of polycarboxylate water reducer and high water-reducing rate, the use of polycarboxylate water reducer to prepare various types of high-performance concrete above C45 can greatly reduce engineering costs and have significant technical and economic benefits; For the preparation of concrete below C45, although the cost of HK-1 polycarboxylate water reducer is high, it can reduce the overall cost of concrete by increasing the amount of mineral admixtures, which also has certain technical and economic benefits.
Product Home Page:https://www.dongkepce.com/polycarboxylate-superplasticizer
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Compatibility of polycarboxylate superplasticizer with other admixtures.
Polycarboxylic acid high-efficiency water reducing agent is characterized by low dosage and high water reducing rate.
Polycarboxylic acid water reducing agent with high efficient water reducing performance is often used in construction concrete.
Polycarboxylate superplasticizer is a new generation of water-reducing agent based on modified polycarboxylic acid.
Polycarboxylate (PCE) superplasticizers are known as high range water-reducing admixtures in concretes, such as ready-mix concretes, self-compacting concretes (SCC), ultra-high strength concretes (UHPC) and at the same time give an extended slump retention.
The polycarboxylic acid-based high-performance water-reducing agent, has truly designed an effective molecular structure based on the mechanism of dispersed cement. It has a super-dispersed type and can prevent concrete slump loss.