Chemical Admixtures - Cement
Accelerating admixtures are especially useful for modifying the properties of concrete in cold weather. Superplasticizers, also known as plasticizers or high-range water reducers (HRWR), reduce water content by 12 to 30 percent and can be added to concrete with a low-to-normal slump and water-cement ratio to make high-slump flowing concrete.
Polycarboxylate Superplasticizers - Concrete Construction
The PCE superplasticizer replaced both the PNS/lignin and Type A water-reducing products at about one-third the dosage rate. Also, note the 50% drop in AEA dosage rate with the PCE admixed concrete to obtain the same air content.
Use of Water Reducers, Retarders, and Superplasticizer
The use of superplasticizers may produce high strength concrete (compressive strength up to 22,000 psi). Superplasticizers can also be utilized in producing flowing concrete used in a heavy reinforced structure with inaccessible areas. Requirement for producing flowing concrete is defined in ASTM C 1017.
Superplasticizer - an overview | ScienceDirect Topics
Superplasticizers used in concrete come in four main groups: – Sulfated naphthalene formaldehyde (PNS); – Sulfated melamine formaldehyde (PMS); – Vinyl copolymers (VCPs); – Polycarboxylic ethers (PCEs). 8.2.1 Polynaphthalene sulfonates In 1930, PNS was used for the first time in the manufacture of synthetic rubber and the textile chemicals.
Superplasticizer
Superplasticizers ( SPs ), also known as high range water reducers, are additives used in making high strength concrete. Plasticizers are chemical compounds that enable the production of concrete with approximately 15% less water content. Superplasticizers allow reduction in water content by 30% or more.
- What is PCE Based admixture?
- The PCE based admixture can significantly reduce the amount of cement and improve the fluidity and pumpability of concrete while ensuring the strength and durability of concrete. Therefore, PCE superplasticizer can be widely used in these projects, such as water conservancy, eletrical power, ports, railway ,bridge, highway and buldings,etc.
- What is PCE superplasticizer?
- PCE superplasticizer is a high-performance water reducing agent that integrates many functions such as high water reduction, high collapse retention, reinforcement, shrinkage, and environmental protection. It is also an ideal admixture for preparing high-strength and high-performance concrete.
- What are chemical admixtures used for?
- Also, chemical admixtures enable the manufacture and construction of special concretes such as high fluidity concrete, high strength concrete, underwater concrete, and sprayed concrete. This three-part article reviews recent developments in admixture chemistry and applications, with a focus on polycarboxylate (PCE) superplasticizers and retarders.
- Why are PCE superplasticizers used in gypsum wallboards?
- This effect is highly desirable, because it allows thinner concrete liners to support the tunnel. Apart from concrete, PCE superplasticizers now are also used in large quantities in the manufacture of gypsum wallboards .
- Why is PCE used in shotcrete?
- In shotcrete, PCEs can reduce the water-to-cement ratio to lower values than those attainable from polycondensates which results in higher strength of concrete. This effect is highly desirable, because it allows thinner concrete liners to support the tunnel.
- Are PCE-superplasticizers suitable for low carbon cement & concrete?
- Both the water reduction and slump retention are required, PCE-superplasticizers are widely used. In addition to higher performance of concrete, reduction of CO 2 is becoming an important issue in the cement and concrete field. The development of superplasticizers for such low carbon cement and concrete is also important.
