For centuries, builders have utilized cement-lime mortar as a common building material in their construction projects. Its blend of cement, lime, sand, and water produces a strong and adaptable material that can be applied to a variety of tasks, such as plastering and bricklaying.
Different grades of cement-lime mortar are available, each with unique properties of its own. The technical specifications of grades 25 and 50, which are common for various kinds of construction work, will be the main topic of this article. By choosing the appropriate mortar for your project, you can ensure a sturdy and long-lasting finish by being aware of these grades.
We’ll go over the main characteristics of cement-lime mortar grades 25 and 50, such as their strength, workability, and recommended applications. Understanding the distinctions between these grades will enable you to make wise choices whether you’re a professional builder or a do-it-yourself enthusiast.
| Grade | Technical Characteristics |
| 25 | Medium strength, suitable for plastering and masonry work, good adhesion |
| 50 | Higher strength, ideal for load-bearing structures, better durability |
- Advantages
- Penetration ability
- Technical characteristics
- Properties
- Density and grades
- Variety
- Dry mix or composition made by yourself
- Method of slaking lime
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Advantages
A unique type of building material with greater elasticity and strength is lime-cement mortar. It can be utilized for finishing work as well as building construction as a binder.
- The mortar can be used as a masonry mortar or a base for plaster. In the first case, it provides reliable adhesion of blocks or bricks. In the second, it is used for external or internal finishing activities.
- The solution can be used to pour monolithic floors, since lime prolongs the hardening period and increases strength properties. This reduces the risk of cracks and promotes uniform distribution of putty.
Penetration ability
Because of the cement-lime mixture’s superior surface adhesion, it completely fills in small cracks and depressions and offers a high fixation strength. The solution can be used in conjunction with wood products because of its strong adhesion. Thus, this technology is used to make plaster for wooden battens.
The mixture can be used for both interior and exterior finishing work on buildings because of its enhanced strength, plasticity, and moisture resistance. Finishing work in bathrooms, on facades, or on the foundation where it meets the blind area is in demand.
A popular and adaptable building material, cement-lime mortar is renowned for its strength, workability, and durability. The terms "Grades 25 and 50" refer to the compressive strength of the mortar; Grade 25 is appropriate for internal plastering and light structural work, while Grade 50 has a higher strength and is therefore best suited for more difficult construction projects. These mortars combine the lime’s flexibility and cement’s binding qualities to create a mixture that is more easily applied and more appropriate for a variety of masonry projects.
Technical characteristics
The following elements form the foundation of a superior solution:
- Cement mixture.
- Sand.
- Slaked lime.
- Water.
Selecting solely the slaked lime is crucial when using it. If this isn’t done, the liquid will be added to the solution and bubbles will form, causing extinguishing. The plastered surface will consequently start to fracture. A similar procedure weakens and lowers the quality of the final solution.
In addition to keeping rodents and other pests out of the room, lime inhibits the growth of harmful bacteria and fungi. GOST standards govern the properties and composition of contemporary building mixtures. This makes it possible for you to standardize their technical attributes and verify that they adhere to the specifications.
The document also lists styling characteristics, quality indicators, and requirements for moving solutions. Depending on the environment of use, it controls the qualities of masonry solutions, plastering materials, and interior decoration.
Properties
The properties listed below define cement and lime solutions:
- Mobility.
- Water resistance from 90%.
- The degree of stratification up to 10%.
- Working temperature up to 0 ° C.
- Average density.
- The degree of humidity (this indicator is typical for dry mixes).
The proportions of cement and lime mortar are chosen based on the kind of surface they will be applied to and the circumstances surrounding their use. The fat content of the mixture is a term used in the construction industry. The amount of binders contained in the masonry mortar’s composition determines it.
- Normal. These include a material with universal plasticity, which can be used in different environments. Such solutions are free from the problem of shrinkage and cracking of the coating.
- Lean. Characterized by minimal shrinkage and can be used for any activities on cladding of premises.
- Fat. Represent highly plastic compositions with a high content of binders. The solution is intended for masonry.
Special ingredients that impact plasticity are added to the composition to alter the amount of fat content. This can be either lime, which acts in the opposite direction, or porous sand, which lowers the parameter.
Density and grades
Different densities can be found in cement-lime mortar. The raw materials and component ratios are the determining factors. The materials that are most frequently used are as follows:
- With low density – up to 1500 kg / m³.
- With high density – from 1500 kg / m³.
Materials are separated into various grades based on the proportions. This can include Dr. and lime mortars M50, M75, and M100. Strength and moisture resistance have increased in the final two grades, 50 and 100. Because the composition’s additives don’t contain crushed stone, they have a homogenous structure.
Industrial and civil facilities are built using grades 100 and 75. Different proportions of cement, sand, and lime are combined to create the compositions.
Surface plastering can be done using solutions M25 and M50. Their low cost and simplicity of production set them apart.
These solutions are used in the construction of baths and other high-humidity buildings because they are required at humidity levels higher than 75%. Lime also combats fungal growth on walls.
Variety
There exist multiple varieties of lime mortars used in plastering.
- Basic. Suitable for rough surface treatment and sealing of defects and depressions.
- Decorative. Designed for painting surfaces, changing their appearance and creating a shimmering effect. The composition of such plasters includes special additives, plasticizers and hydrophobic elements.
- Special. They are intended to improve the performance of treated buildings, perform moisture protection, sound insulation and heat insulation functions.
Dry mix or composition made by yourself
Cement-lime compositions’ main benefit is their low cost. Because they use less material when applied to various structures, they are less expensive than cement and sand mixtures.
However, because the composition includes its various fractions and does not call for the presence of plasticizers, options containing sand have less plasticity. Moreover, the material needs more leveling because it fills pores poorly.
Several producers produce dry mixes of cement and lime solutions, which are sold as such. Nevertheless, making them by hand is simple.
Moscow offers a broad range of products for sale from various brands, each with unique performance characteristics and operating environments. You have to follow the markings on the packaging to select the right type.
It’s crucial to dilute the solution with water according to the ratios listed on the container before applying it. Using a construction mixer will result in more efficient mixing. When there is no electricity available, a simple shovel and trowel are utilized.
In the event that manual production is used, you must prepare the raw materials and mix them according to the specified brand in the appropriate amounts. The only lime that should be used when making a cement-lime mixture is slaked lime. Should it not be accessible, you will need to slake it on your own.
Method of slaking lime
It’s crucial to take care of your personal safety equipment and adhere to the detailed instructions when you begin preparing lime.
- In a container, mix lime and water in a ratio of 1:1.
- When the mixture boils, which will be confirmed by a strong reaction, you will need to add a small amount of liquid so that it completely covers the raw materials.
- After this, the composition is thoroughly mixed and covered with a lid.
- The material is kept for 14 hours without use. This process does not require much effort, but takes a lot of time.
As a result, most builders purchase slaked lime from a store.
If the slow and medium slaking method is required to slake lime, then you must adhere to the following guidelines:
- First of all, you need to dig a hole and place a container made of a wooden box with dimensions of 1.5×2 m near it. A damper with a small mesh is placed at the bottom.
- Lump lime is laid on ¼ of the volume. Then a small amount of water is added. When the lumps fall apart into small pieces, you will need to add a little more liquid and mix everything thoroughly.
- After the mixture has been successfully slaked, it must be diluted to a thick consistency, remove the damper and drain the solution through a sieve.
- To prevent rapid drying, the mass is covered with clean sand.
It is preferable to carry out extinguishing procedures—regardless of the technique—while wearing a tarpaulin-covered suit, gloves, and safety glasses. Burns may result from the mixture penetrating into skin that is not protected.
Grades 25 and 50 cement-lime mortars provide adaptable solutions for a range of construction requirements. Finding the appropriate material for a given task can be facilitated by knowing the technical features of these grades, whether you’re working on plastering, bricklaying, or other masonry tasks.
Grade 50 offers better durability and load-bearing capacity, while grade 25 is best for lighter applications where high strength is not a priority. Both grades offer good workability and long-lasting performance by combining the advantages of cement and lime.
You can guarantee a robust and dependable finish that fulfills the requirements of your project by choosing the right grade and adhering to best practices in mixing and application.
