How to choose superplasticizers (plasticizer) for concrete, cement mortar, proportions

Using the proper mix when working with concrete or cement mortar can significantly alter the outcome. Superplasticizers, sometimes referred to as plasticizers, are an essential component that can raise the mix’s quality. Without adding more water, these additives help make the mixture more workable.

Selecting the ideal superplasticizer can be difficult, especially with so many alternatives. It’s critical to comprehend their operation and the appropriate ratios to use for your particular project. This will assist you in getting the best strength, longevity, and usability out of your mortar or concrete.

This post will explain the fundamentals of superplasticizers, assist you in selecting the best one, and provide advice on how to use them. This information will assist you in making better decisions for your concrete projects, regardless of whether you’re a professional or a do-it-yourself enthusiast.

Factor to Consider Recommendation
Type of Concrete or Mortar Choose a superplasticizer compatible with the specific type of concrete or mortar you"re working with, such as high-strength or precast concrete.
Water Reduction Select a superplasticizer that provides the desired level of water reduction without compromising workability.
Dosage Follow the manufacturer"s recommended dosage for the best performance, typically ranging from 0.5% to 2% of the cement weight.
Mixing Process Ensure the superplasticizer is added during the mixing process, either with the water or after the initial mix, to achieve optimal results.
Environmental Conditions Consider the temperature and humidity of your working environment, as these factors can affect the performance of the superplasticizer.

Plasticizers for concrete mix: what is it?

Modifying additives are composites, either liquid or dry, that, when dissolved in water, produce neutral or alkaline compounds. These substances, which can be either organic or inorganic, are used to regulate and control the state of cement mixtures as they hydrate and harden.

Modifier additives can be produced by processing industrial waste and cellulose concentrates from the following businesses:

  • forest chemicals;
  • agrochemicals;
  • petrochemical industries, etc.

Surface-active compounds are the most widely used kind of plasticizing additives. These materials are the basis for almost the whole range of currently used modern modifiers. Superplasticizers and hyperplasticizers are the most potent of them.

They alter the deformation characteristics of cement systems and aid in lowering water consumption, which in turn improves the quality of the crystalline structure of concrete by influencing the processes taking place in the structure of mixtures during the first stage of laying.

Purpose and application

Superplasticizers are all-purpose additives that give mixtures good workability and favorable hardening dynamics.

These modifiers are used to improve the following attributes of reinforced concrete structures and to produce plastic, highly mobile concrete solutions (P1–P5) without compromising their strength characteristics:

  • water resistance;
  • frost resistance;
  • wear resistance;
  • resistance to chemical influences;
  • heat resistance.

Actually, there is more to this list. It is impossible to count the number of additives with various mechanisms of action. The superplasticizer C3 is the most well-liked among them. Brown liquids or powders are the forms in which it is produced.

It has shown excellent performance in the production of the following goods:

  • concrete floors;
  • paving slabs;
  • garden paths, etc.

The operational requirements for finished concrete structures dictate the volume of consumption and product consumption.

Composition of the plasticizer

Superplasticizers are categorized based on a number of factors, including the substances’ chemical makeup and mode of action (either electrostatic or steric).

  • melamine formaldehyde polycondensate;
  • sulfonated naphthalene-formaldehyde polycondensate;
  • lignosulfonates;
  • polyacrylates;
  • polycarboxylates.

A material known as classic superplasticizer (C3) influences the structure of cement by causing the binder grains to repel one another electrostatically.

It is made up of the following substances:

  • sulfonated polycondensate (80%);
  • sodium sulfate (7-10%);
  • water (10%).

Hyperplasticizers are additives of a new generation. Large steric effects, which are twice as strong as those of plasticizers, are the primary mechanism of action of additives.

Need for use

The need to achieve certain outcomes in the manufacturing of products made of reinforced concrete and to boost operational economics make the use of a plasticizing additive necessary.

  1. In the case of obtaining concrete grade M600 using Portland cement grades 400-500 (technological requirements of the project, etc.).).
  2. To reduce cement consumption.
  3. When replacing coarse-grained aggregate in mixtures with less durable – fine-grained.
  4. To increase the stability of structures under axial tension, compression without increasing the consumption of binders.

Positive characteristics of the additive

The following are some benefits of the substance:

  • increases the mobility of concrete to P5;
  • improves the plasticity of the solution (workability) by 1.5 times;
  • reduces the W/C ratio by 25%;
  • increases the strength parameters of products by 25%;
  • hydrophobic properties – W10 and higher;
  • frost resistance value – F300;
  • adhesion of mixtures to steel reinforcement increases by 1.7 times.

Negative effects from the use of C 3

  1. When introducing the additive into concrete solutions, the mobility of the mixtures increases, but their hardening rate decreases. To stabilize this indicator, it is necessary to use the additive together with a setting accelerator.
  2. The superplasticizer is toxic and according to its characteristics is classified as hazard class 3. The substance may have an irritating effect on the respiratory system, mucous membranes of the eyes, and unprotected skin.
  3. Due to the presence of sodium sulfate in the additive, there is a risk of efflorescence on the surface of products.

The workability, strength, and durability of your concrete or cement mortar mix can all be considerably increased by selecting the appropriate superplasticizer. Whether you’re working on a big construction project or a small repair, you can get the best results for your particular project by knowing the various types that are available and how to measure and mix them properly.

Instructions for using plasticizer

Prepare a modifier solution at a positive air temperature in clean and washed tanks, protected by a light canopy from precipitation.

The consumer determines the conditions and timing of the additive’s preparation based on the needs for the final product. The mineral makeup of the fillers and binder determines the product’s quality.

The additive must be added to the concrete mixer in the form of a liquid suspension. The optimal structure of the substance is selected based on the manufacturer’s recommendations (located on the product packaging) and process conditions.

When the plasticizer is added with the second part of water, cement mixtures experience the greatest plasticizing effect.

Working with powder

Particulars of the additive manufacturing process:

  1. Pour the calculated amount of warm water into the required volume of dry mixture prepared in advance and mix.
  2. Then add the diluted additive solution.
  3. Without turning off the mixer, pour sand, cement and fillers into the container.
  4. Mix the components until a plastic homogeneous mass is obtained.

Working with a ready-made solution

Working with a ready-made liquid composition is significantly simpler:

  1. Be sure to read the instructions on the packaging. According to the established recommendations, dilute the mixture with the required amount of water.
  2. Pour the solution into the mixer.
  3. Add dry components.
  4. Mix until the desired consistency is obtained.

Composition consumption per 100 kg of cement

The performance characteristics of the concrete solution, the amount of active modifiers (apart from C3), the dispersion of the cement, and the calculated content of tricalcium aluminate in the binder all influence the dosage of the additive.

The instructions suggest using 0.4–1% of the binder consumption as the amount of liquid plasticizing mixture. Through experimentation, the ideal dosage is determined.

Manufacturers of modifying compounds recommend adding 3-5 liters of finished mixture and 0.5 kg of dry mixture per 100 kg of cement.

Plasticizer brands with 3

Superplastifier manufactures products for numerous businesses both domestically and internationally. As a result, the chemical makeup of various manufacturers may vary from one another. Furthermore, altering mixtures may be designed for a different kind of task, such as producing paving slabs or building high-rise structures monolithically.

To ensure that your product selection is error-free, seek advice from experts and carefully read the supplier’s instructions and recommendation found on the product’s packaging.

For concrete or cement mortar, selecting the appropriate superplasticizer can have a big impact on the mix’s quality and workability. These additives aid in increasing the final product’s strength, decreasing its water content, and improving flow. Understanding the various varieties and their unique advantages will help you customize your mix to your project’s requirements.

It’s crucial to add superplasticizers in the prescribed amounts as well. If you use too little, the desired effects might not materialize, but using too much can cause problems like segregation or delayed setting. Always refer to the manufacturer’s instructions and take into account the particular needs of your project, including the kind of cement to be used and the surrounding circumstances.

By paying attention to these factors, you can achieve a more durable, workable, and reliable concrete or cement mortar mix, ensuring your project stands the test of time. Superplasticizers offer a simple yet effective way to enhance your construction work, making the investment well worth it.

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Anna Vasilieva

Journalist with a technical education, specializing in construction topics. I can explain complex technical topics in simple and accessible language.

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