Blog

A hollow glass microsphere is a kind of hollow microsphere with a thin wall, high strength, and smooth surface, which is a new kind of micron-level light inorganic material developed in the 1950s and 1960s. It not only has the advantages of low density, high strength, low thermal conductivity, high wave penetration, and good stability, but also has insulation, self-lubrication, sound insulation, fire resistance, corrosion resistance, radiation, and other excellent properties that other non-metallic materials do not have.

Some byproducts of fly ash were found in the early years. Under the microscope, they were pearl-like hollow beads with diameters of 20~200μm and shell thickness ranging from 5% to 30% of the diameter. Its main components are SiO2, Al2O3, CaO, MgO, Na2O, and K2O. This sphere has a small specific gravity, high surface pressure, strong wear resistance, good flame retardant, and good acid resistance, high-temperature resistance, so it has been excavated out of the new function.

In the early stage of development, artificial hollow glass beads are mainly used in aerospace, national defense, and other cutting-edge applications due to their high cost.  Later, the United States and Japan took the lead in the development and mass production of hollow glass beads.

Now, hollow glass beads are widely used in aerospace, 5G communications, military marine, lightweight vehicles, energy-conservative building, oilfield cementing, rubber and plastic elastomers, and many other fields. Specifically,

In 5G communications, hollow glass beads can help improve the transmittance due to their hollow glass material with a low dielectric constant of 1.0~2.0. It can be used to make 5G base station and radome materials, 5G mobile phone frame and backplane, Internet of things equipment, etc.

In rubber, elastomer, and lightweight vehicles, hollow glass beads have a good role in reducing the specific gravity, rubber plastic, and other composite materials can reduce weight by 8%~10%. In addition, hollow glass beads can also effectively improve the processing performance of materials, increase rigidity and resilience, improve the material heat insulation, sound insulation, noise reduction, flame retardant, and a series of special functions, widely used in shoes, elastic pillows, car shell, special parts, and other products.

In the coating industry, the micron particle size of hollow glass beads and hollow microspheres effect give the paint a better heat insulation effect. Therefore, it could be used for military and aerospace equipment, oil pipeline, oil tank, communication base stations, large storage silos, etc.

As an anti-corrosion coating, the addition of hollow beads makes the product has more excellent anti-fouling, anti-corrosion, anti-ultraviolet, anti-yellowing, and anti-scratch effect, so it can be used for weatherproof sunscreen and heat insulation outdoor coatings, automotive coatings, anti-fouling coatings, anti-corrosion coatings, etc.

In the adhesive industry, the addition of hollow beads can reduce the density of the adhesive, reduce the volume cost, improve the rheological properties of the adhesive, improve the thixotropy and chemical corrosion resistance, and give the product better sound insulation, heat insulation, low thermal conductivity, and dielectric properties, more excellent anti-warping, anti-cracking properties. Hollow beads are widely used in silicone, epoxy resin, acrylic acid, polyurethane, synthetic rubber, and other adhesives. 

In addition, hollow glass beads are typically used in oilfield cementing, which has long been the most widely used field. The use of oil field cementing includes low-density drilling fluid and cementing cement. 

Low-density drilling fluids added with hollow glass beads are not only more chemically stable, but also have excellent fluidity and better lubrication, which can reduce friction during drilling, extend the service life of drill pipe and drill bit, and other equipment, but also greatly improve drilling speed and operational efficiency. Hollow glass beads are added in the cementing cement products of low density, high strength, easy flow features, is to address the low pressure, easy leakage well solid water mud loss one of the main ways of low return, can effectively control the water loss rate, prevent pollution, during 24h the compressive strength can reach more than 15Mpa, and it can improve cementing quality, prolong the life of the well.

Luoyang Tongrun Nano Technology Co. Ltd. (TRUNNANO) is a trusted global chemical material supplier & manufacturer with over 12-year-experience in providing super high-quality chemicals and Nanomaterials, including silicon powder, nitride powder, graphite powder, zinc sulfide, calcium nitride, 3D printing powder, etc.

If you are looking for high-quality hollow glass microspheres, please feel free to contact us and send an inquiry. (sales@cabr-concrete.com)

There are many reasons for slump loss, mainly in the following aspects:

1. Influence of raw materials

Whether the cement used and the pumping agent are matched and adapted must be obtained through the adaptability test. The optimum amount of the pumping agent should be determined through the adaptability test with the cement cementitious material. The amount of air-entraining and retarding components in the pumping agent has a greater impact on the loss of concrete slump. If there are many air-entraining and retarding components, the slump loss of concrete will be slow, otherwise the loss will be fast. The slump loss of concrete prepared with naphthalene-based superplasticizer is fast, and the loss is slow when the low positive temperature is below +5 °C.

If anhydrite is used as the setting modifier in the cement, the slump loss of the concrete will be accelerated, and the early strength component C3A content in the cement is high. If "R" type cement is used, the cement fineness is very fine, and the cement setting time is fast, etc. It will cause the slump loss of concrete to accelerate, and the speed of concrete slump loss is related to the quality and amount of mixed materials in the cement. The C3A content in the cement should be within 4% to 6%. When the content is lower than 4%, the air-entraining and retarder components should be reduced, otherwise the concrete will not solidify for a long time. When the C3A content is higher than 7%, it should be increased. Air-entraining retarder component, otherwise it will cause rapid loss of concrete slump or false setting phenomenon.

The mud content and mud block content of the coarse and fine aggregates used in concrete exceed the standard, and the content of crushed stone needle flake particles exceeds the standard, which will cause the slump loss of concrete to accelerate. If the coarse aggregate has a high water absorption rate, especially the crushed stone used, after being exposed to high temperature in the summer high temperature season, once it is put into the mixer, it will absorb a large amount of water in a short period of time, resulting in accelerated slump loss of the concrete in a short time (30min). 

2 Influence of stirring process

The concrete mixing process also affects the slump loss of concrete. The model of the mixer and the mixing efficiency are related. Therefore, the mixer is required to be regularly repaired and the mixing blades should be replaced regularly. Concrete mixing time should not be less than 30s. If it is less than 30s, the slump of concrete is unstable, resulting in relatively accelerated slump loss.

3 Temperature effects

The effect of temperature on the slump loss of concrete is of particular concern. In hot summer, when the temperature is higher than 25°C or above 30°C, the concrete slump loss will be accelerated by more than 50% compared with that at 20°C. When the temperature is lower than +5°C, the concrete slump loss will be very small or not lost. . Therefore, during the production and construction of pumped concrete, pay close attention to the influence of air temperature on the slump of concrete.

The high use temperature of the raw materials will cause the concrete to increase in temperature and accelerate the slump loss. It is generally required that the concrete discharge temperature should be within 5 ~ 35 ℃, beyond this temperature range, it is necessary to take corresponding technical measures, such as adding cold water, ice water, groundwater to cool down and heat the water and the use temperature of raw materials and so on.

It is generally required that the maximum operating temperature of cement and admixtures should not be higher than 50 °C, and the operating temperature of concrete pumped heating water in winter should not be higher than 40 °C. There is a false coagulation state in the mixer, and it is difficult to get out of the machine or transport it to the site for unloading.

The higher the temperature of the cementitious materials used, the worse the water-reducing effect of the water-reducing components in the pumping agent on concrete plasticization, and the faster the concrete slump loss. The concrete temperature is proportional to the slump loss, and the slump loss can reach about 20-30mm when the concrete increases by 5-10℃.

4 Strength levels

The slump loss of concrete is related to the strength grade of concrete. The slump loss of concrete with high grade is faster than that of low-grade concrete, and the loss of crushed stone concrete is faster than that of pebble concrete. The main reason is that it is related to the amount of cement per unit.

5 Concrete state

Concrete statically loses slump faster than dynamic. In the dynamic state, the concrete is continuously stirred, so that the water-reducing components in the pumping agent cannot fully react with the cement, which hinders the progress of cement hydration, so that the slump loss is small; in the static state, the water-reducing components are fully in contact with the cement, The cement hydration process is accelerated, so the concrete slump loss is accelerated.

6 Transport machinery

The longer the transportation distance and time of the concrete mixer truck, the less free water of the concrete clinker due to chemical reaction, water evaporation, water absorption of the aggregate and other reasons, resulting in the loss of concrete slump over time. The barrel also causes mortar loss, which is also an important cause of concrete slump loss.

7 Pour speed and time

In the process of concrete pouring, the longer the time for the concrete clinker to reach the silo surface, the rapid reduction of free water in the concrete clinker due to chemical reactions, water evaporation, aggregate water absorption and other reasons, resulting in slump loss. , especially when the concrete is exposed on the belt conveyor, the contact area between the surface and the external environment is large, and the water evaporates rapidly, which has the greatest impact on the slump loss of the concrete. According to the actual measurement, when the air temperature is around 25℃, the on-site slump loss of concrete clinker can reach 4cm within half an hour.

Concrete pouring time is different, which is also an important cause of concrete slump loss. The impact is small in the morning and evening, and the impact is greater at noon and afternoon. The temperature in the morning and evening is low, the water evaporation is slow, and the temperature in the afternoon and afternoon is high. The worse the fluidity and cohesion, the more difficult it is to guarantee the quality.

TRUNNANO is a concrete additives supplier with over 12 years experience in nano-building energy conservation and nanotechnology development. We accept payment via Credit Card, T/T, West Union and Paypal. Trunnano will ship the goods to customers overseas through FedEx, DHL, by air, or by sea.

If you are looking for high quality concrete superplasticizer, please feel free to contact us and send an inquiry.

sales@cabr-concrete.com

Foam concrete is lightweight concrete made from cement, sand or fly ash, water, and foam. Foam concrete is a form of foam grouting or foam mortar. Foam concrete can be defined as a cementitious material consisting of at least 20% foam that is mechanically engrafted into plastic mortar. The dry density of foam concrete can vary from 300 to 1600 kg/m3.  The compressive strength of foam concrete measured after 28 days ranged from 0.2 to 10N/mm2 or higher.

The difference between foam concrete and aerated concrete is the amount of entrained air. Aerated concrete takes in 3% to 8% of the air. It is also different from retarded mortar and aerated concrete, for the same reason of the percentage of the air entrained. In the case of a slow-setting mortar system, it is 15 to 22 percent. In the case of aerated concrete, the bubbles are chemically formed. 

Foam concrete History

Foam concrete has a long history. It was first put into use in 1923, initially as an insulation material. In the past 20 years, improvements in manufacturing equipment and better-quality foam-making agents have allowed foam concrete to be used on a large scale. 

Foam concrete Composition

The composition of foam concrete varies with the desired density. In general, foam concrete with a density of less than 600kg/m 3 will contain cement, foam, water, and some fly ash or limestone dust. In order to achieve a higher density of foam concrete, sand can be used. For heavier foam concrete, the base mixture is 1:1 to 1:3, the ratio of filler to Portland cement (CEM I). For higher densities, say greater than 1500kg/m 3, more packing and medium sand are required. In order to reduce density, the amount of filler should be reduced. The foam concrete with a density less than 600kg/m3 is recommended to be eliminated.

The maximum size of sand used can be 5mm.  Use fine sand up to 2mm and pass 60% to 95% through a 600-micron screen.

Foam concrete Material

Cement for foam concrete

Ordinary Portland cement is commonly used, and quick-hardening cement can also be used when necessary. Foam concrete can be mixed with a variety of cement and other combinations, for example, 30% cement, 60% fly ash, and 10% limestone. Cement content ranges from 300 to 400 kg/m3.

Sand for foam concrete

Ash 

Auxiliary cementitious materials such as fly ash and grated granular blast furnace slag have been widely used in the manufacture of foam concrete. The amount of fly ash used is between 30% and 70%. White GGBFS range from 10% to 50%. This reduces the amount of cement used and is economical. Silica fume can be added to increase strength; The mass percentage is 10%. 

Bubble 

Hydrolyzing proteins or synthesizing surfactants are the most common forms of foam manufacture. Synthetic-based foams are easier to handle and cheaper. They can last longer. These foams require less energy to produce. Protein-based foams are expensive but have high strength and performance. There are two types of foam: wet foam and dry foam. Wet foam with a density of less than 100 kg/m3 is not recommended for the manufacture of foam concrete. They have a very loose structure of large bubbles.  For the fine mesh, agents and water are sprayed. This process produces foam with bubbles ranging in size from 2 to 5 millimeters. Dry foam is highly stable in nature. Solutions of water and foaming agent are restricted to the mixing chamber by compressed air. The resulting foam has a smaller bubble size than wet foam. That's less than a millimeter.  These give a uniformly arranged bubble structure. 

TRUNNANO is a reliable foaming agents supplier with over 12-year experience in nano-building energy conservation and nanotechnology development.

If you are looking for high-quality CLC foaming agents, please feel free to contact us and send an inquiry. (sales@cabr-concrete.com)

We accept payment via Credit Card, T/T, West Union, and Paypal. TRUNNANO will ship the goods to customers overseas through FedEx, DHL, by air, or by sea.

Cement foaming machine needs auxiliary test machine to help achieve better foaming effect in construction application. Cement foaming agent is a chemical admixture, which is added to cement. Compensate for shrinkage and tension of steel bars to produce prestress and to fully fill cement gaps.

According to the construction requirements and the quality requirements for foamed cement, we believe that the following requirements are put forward for the foaming agent:

1. The amount of foaming, the actual amount of foaming is not only a physical indicator, but also a cost indicator, if the amount of foaming is smaller, but the price is lower.

2. Foam strength is a comprehensive index of the collapse degree, shrinkage degree and foam stabilization time of foamed cement products.

3. Foam pore size and uniformity: The foam pore size and uniformity are the reliable guarantee for the strength index and thermal insulation index of the finished product. Only products with ideal pore size can be regarded as good products.

4. The purity of the foaming agent and the cleanliness of the foaming agent play a suitable and protective role for more and more sophisticated equipment. Large-scale continuous operation equipment should minimize the failure rate in its operation during operation, otherwise, It will seriously affect the quality of the project and the progress of the project. At the same time, too many impurities will affect the hydration reaction of the cement itself, resulting in a decrease in quality.

5. Non-corrosive, requires foaming agent, no corrosive pollution to the equipment environment, and has environmental protection performance.

6. Persistence of foam: This indicator has been highly demanded by people in the past. Some people pursue the longer the duration of the foam, the better. In fact, it is not necessary to pursue too long a stable foam time. We believe that the foam emitted by the foaming agent is Within the scope of application, its duration only needs to exceed the initial setting period of the cement product, because the existence of foam is meaningless when the product enters the initial setting period, and the ideal stabilization time exceeds 24 hours, which can meet various construction requirements. 

TRUNNANO is a concrete additives supplier with over 12 years experience in nano-building energy conservation and nanotechnology development. We accept payment via Credit Card, T/T, West Union and Paypal. Trunnano will ship the goods to customers overseas through FedEx, DHL, by air, or by sea.

If you are looking for high quality foaming agent, please feel free to contact us and send an inquiry.

sales@cabr-concrete.com