Foam concrete is a kind of concrete with lightweight and has ideal strength. Because of the hollow structure in foam concrete, it has the function of absorbing heat and isolating sound.
The density of foamed concrete is 300-1200 kg/m3, and the thermal conductivity is between 0.08-0.3W/ (m ·K).
Foam concrete is widely used in CLC blocks, lightweight partition panels, roof insulation, floor cushion construction, floor heating backfilling, and other occasions.
At the same time, foam concrete is also a good sound absorption material, which can be used in highway sound insulation boards, sound absorption boards, and other fields.
Generally speaking, foam concrete is a kind of building material with multi-function, environmental protection, and economy, which has a wide application prospect.
As an important construction equipment, the safe use of concrete foaming machines is crucial for ensuring construction quality and worker safety. When operating this type of equipment, it is necessary to pay attention to some key safety precautions to ensure efficiency and safety. The following are the safe usage methods for concrete foaming machines.
Before operating the concrete foaming machine, as a staff member, it is necessary to take safety precautions first. This includes wearing work clothes, hats, and suitable shoes, as well as wearing protective glasses. In addition, to ensure good ventilation conditions, it is necessary to place the work site in a well ventilated area and maintain cleanliness and hygiene at the workplace.
During operation, especially in high temperature environments, it is necessary to pay attention to changes in ambient temperature. When the ambient temperature is too high, the concrete foaming machine may exhibit unpredictable behavior, thereby increasing the risk of use. Therefore, if the ambient temperature is too high, it is advisable to avoid using a concrete foaming machine as much as possible or ensure that the equipment has been fully cooled before use.
The cleanliness of concrete foaming machines has a significant impact on their effectiveness. If there are impurities inside or outside the equipment, such as dust, mud, etc., It could interfere with it's normal functioning of device or even cause malfunction or damage. Therefore, the equipment should be kept clean before and after operation.
During the production process, a certain proportion of flame retardants need to be added to the concrete foaming machine. The addition ratio can usually be maintained at 10% -15%. When adding flame retardants, operators need to wear corresponding protective equipment, such as protective gloves, protective glasses, etc., to prevent possible chemical harm. At the same time, it is necessary to ensure uniform mixing during the addition process to ensure that the flame retardant can be fully integrated into the concrete.
Check the safety valve of the cement foaming machine, hydraulic system steel pipes and hoses, connections, and oil cylinders, and find any wear and cracks. Check the pipeline from the safety valve to the inlet of the oil cylinder to ensure that there is no diarrhea or caused by impact and wear. The deformation ensures the completeness and complete fastening of the connecting piece.
Inspection and treatment of leaking parts of cement foaming machine. The main leak detection parts are: liquid level gauge, oil drain plug, oil pump, oil motor shaft and shell joint surface, oil cylinder head joint surface, oil cylinder piston rod extension, hydraulic valve joint surface, adjustment handle extension Parts, oil pipe joints, oil cylinders.
The lubricating grease of the cement foaming machine must be sufficient and clean at all times, and the lubrication pipeline joints must not leak. Check the lubrication of each operating part at any time. If there is a part lacking oil, stop the machine for inspection immediately to prevent accidents.
During the operation process, attention should be kept focused and distractions or other unrelated tasks should be avoided. At the same time, it is necessary to always pay attention to changes in the surrounding environment to prevent potential hazards from occurring. Secondly, it is necessary to avoid excessive twisting or compression of the equipment to prevent equipment damage or personal injury. Do not operate the concrete foaming machine without receiving professional training. For personnel who are not familiar with the operation process, it is necessary to operate under the guidance of professional personnel. If encountering any problems or difficulties, immediately stop the operation and seek professional assistance. Do not attempt to solve it on your own to avoid causing greater loss or injury.
During use, staff should regularly inspect and maintain the various functions of the equipment to ensure its normal operation. If any abnormalities or malfunctions are found, immediately stop using them and contact professional personnel for repair.
After the operation is completed, a comprehensive inspection and cleaning of the equipment should be carried out. This includes cleaning up residues and debris inside the equipment, checking for damage or wear on various components, etc. If the equipment is not in use for a long time, regular maintenance should be carried out. This includes replacing lubricating oil, inspecting fasteners, etc. While at the same time the charging device or battery must be checked on a regular basis to ensure that it is able to perform as expected when it is needed.
During equipment maintenance and upkeep, the cleanliness of the equipment should be maintained. Avoid leaving any debris or dirt on the equipment to prevent any impact on its normal operation. Secondly, pay attention to the temperature and pressure changes of the equipment. If abnormal temperature or pressure changes are found, maintenance should be immediately stopped and inspected.
After maintenance is completed, the equipment should be properly placed in a designated location or location. Ensure that the equipment is not corroded or damaged by natural factors such as wind and rain. At the same time, it is also necessary to ensure that the equipment does not affect the safety and normal activities of surrounding personnel. If there is any malfunction or damage to the equipment, professional personnel should be contacted immediately for repair or replacement. Do not attempt to repair or replace important components on your own to avoid greater losses or safety hazards.
TRUNNANO is a supplier of foam agents with over 12 years experience in nano-building energy conservation and nanotechnology development. It accepts 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 additives, please feel free to contact us and send an inquiry. (sales@cabr-concrete.com).
High efficiency superplasticizer for concrete is an additive that can significantly reduce the amount of mixing water under conditions where the slump of concrete is basically the same. Specifically, it is a multi-faceted chemical agent that can be used to improve the performance of concrete as well as decrease the quantity of water required for mixing.
The main mechanism of efficient superplasticizers is to adsorb on the surface of cement particles, reduce their surface energy, and form a strong electric field adsorption layer on their surface, causing the dispersion of cement particles and significantly increasing their fluidity. This can reduce the demand for mixing water while maintaining the same slump of the concrete.
It should be noted that the compatibility between high-efficiency superplasticizers and cement can affect the important properties of concrete, such as flowability, setting time, and strength development. Therefore, in practical applications, it is necessary to choose high-efficiency superplasticizers with good compatibility with cement and, at the same time, formulate and use them reasonably according to specific engineering requirements and material characteristics to achieve the best results.
Reducing water consumption: Efficient superplasticizers can significantly reduce water consumption during the concrete mixing process, thereby reducing the shrinkage and cracking tendency of concrete and improving its strength and durability.
Increase fluidity: Efficient superplasticizers can improve the fluidity and pumpability of concrete mixtures, making them easier to pour and vibrate, reducing construction time and labor intensity.
Do not change the setting time of concrete: The high-efficiency superplasticizer basically does not change the initial and final setting times of concrete and will not have a negative impact on the hardening process of concrete.
Enhancing concrete performance: Efficient superplasticizers can enhance the impermeability, freeze-thaw resistance, corrosion resistance, and other properties of concrete, improving its durability.
Environmental protection: superplasticizers that are efficient are not contaminated with harmful substances to human health or the environment. They are green and eco-friendly building materials.
Cost saving: The use of high-efficiency superplasticizers can reduce the amount of cement used, thereby reducing the cost of concrete.
The compatibility between concrete high-efficiency superplasticizers and cement refers to the ability of high-efficiency superplasticizers to effectively reduce the water consumption of concrete while maintaining good fluidity when applied in cement. The compatibility mainly depends on the chemical properties and physical structure of high-efficiency superplasticizers and cement.
The main function of high-efficiency superplasticizers is to adsorb on the surface of cement particles, reduce their surface energy, and form a strong electric field adsorption layer on their surface, dispersing cement particles and significantly increasing their fluidity. There is a viewpoint that the molecules of high-efficiency superplasticizers are mainly adsorbed on cement products in large quantities, while there are very few adsorbed on cement particles. There are also views that high-efficiency superplasticizers adsorb on the surface of cement particles, reducing their surface energy and forming a strong electric field adsorption layer on their surface, causing the dispersion of cement particles and significantly increasing their fluidity.
The compatibility between high-efficiency superplasticizers and cement can affect the important properties of concrete, such as flowability, setting time, and strength development. Efficient superplasticizers with good compatibility can significantly reduce the water consumption of concrete while maintaining good fluidity, which helps to improve the workability and durability of concrete.
On the contrary, if the compatibility is poor, not only can the water consumption not be reduced, but it may also lead to problems such as segregation and bleeding in the concrete, seriously affecting the quality of the project.
In practical applications, we need to select high-efficiency superplasticizers and cement with good compatibility based on specific engineering requirements and material characteristics. At the same time, the need for multi-component compounding of external additives and the preparation of additives with specific engineering requirements have become important aspects for additive manufacturers to strengthen on-site services.
People initially thought that superplasticizers were incompatible with cement, often when cement or concrete set abnormally. However, long before the invention of the superplasticizer for concrete, people were using Portland cement to prepare concrete. Inappropriate selection of cement raw materials and inappropriate raw material formulation may cause two types of abnormal condensation. One is called flashing, and the other is called false setting. The two types of coagulation have one thing in common that is cement or concrete will lose fluidity for more than ten minutes after adding water. Flash condensation is accompanied by heat release, and the temperature rises sharply, but false condensation does not have this phenomenon. At the same time, these two kinds of abnormal coagulation are far from the conditions for testing concrete coagulation according to the penetration method. That is, when the penetration resistance is 3.5 MPa and 28 MPa, the initial and final setting states are reached, which is a kind of difference between water and silicate. The reaction has nothing to do with the abnormal reaction. The cement and sand are not cemented together due to the gelation reaction of cement and water, forming a real coagulation.
The cause of abnormal coagulation is often because the content of tricalcium aluminate in the clinker is too high, or the ratio between the added gypsum and tricalcium aluminate is inconsistent, or the temperature during cement grinding is too high, resulting in dehydration of dihydrate gypsum. It turns into hemihydrate gypsum. Hemihydrate gypsum reacts quickly when it meets water, causing the concrete to lose fluidity, or the mismatch of alkali and sulfur in the fresh concrete liquid causes the concrete to set abnormally, or the dihydrate gypsum is not used in the cement. The use of anhydrite with low solubility, etc., or the addition of triethanolamine (non-superplasticizer) as an early strength agent, can cause abnormal concrete condensation and other reasons. There are various reasons, but they are not caused by superplasticizers. The superplasticizer existed before it was used in concrete. Because of the water-reducing effect of the superplasticizer, the water consumption in the concrete is reduced, which aggravates these problems and becomes extremely prominent. At first, it was a new type of material as a superplasticizer, so people often misunderstood it as a superplasticizer.
Control of mud content in sand
When the mud content is greater than 2%, it will affect the fluidity of concrete. For fine sand, the method of adjusting the difference can be used to promote the improvement of the workability of concrete. If the fluidity of concrete is reduced, the water reducing molecules will be affected by clay because the soil structure can adsorb water reducing molecules and reduce the content of superplasticizers. Therefore, in order to improve the performance of the superplasticizer, other additives should be added to the superplasticizer.
Incompatible with most materials
Due to the incompatibility between high-performance superplasticizers and most materials, when using superplasticizers, they should be used separately from other superplasticizers in concrete. Therefore, before replacing the superplasticizer, the container should be cleaned first, and then the new superplasticizer should be added to the container. During the production of the superplasticizer, it also needs to be separated for production. At the same time, superplasticizers cannot be compatible with cement. In recent years, the issue of immiscibility between superplasticizers and cement has attracted people's attention. The adsorption capacity of superplasticizer molecules varies among different brands of cement. Therefore, in order to ensure the fluidity of concrete and avoid the occurrence of superplasticizer molecule adsorption problems, it is necessary to adjust the molecular structure of the superplasticizer.
Gas content control
In order to improve the workability of concrete, it is necessary to strengthen the reasonable control of the air content of superplasticizers. Firstly, when using gas content, it should be used in accordance with relevant standards, using a process of first eliminating and then introducing to retain high-quality small bubbles. If the air content needs to be increased in concrete, an appropriate amount of air entraining agent should be added to the superplasticizer. Currently, the main air entraining agent that is not compatible with high-performance superplasticizers is the rosin thermal polymer air entraining agent.
Temperature control
In high temperature weather, the slump of the superplasticizer will increase, while in low temperature weather, the slump of the superplasticizer will also increase. It can be seen that high-performance superplasticizers are easily affected by temperature. Therefore, in order to avoid this impact, we should strengthen temperature control during the actual construction process to avoid temperature changes. At the same time, the structure of high-performance superplasticizers has a certain degree of adjustability. Under different temperatures, it is necessary to adjust the content of adsorption groups, which can also avoid the impact of temperature on concrete performance.
Application of delayed setting technology
During the long-term use of concrete, in order to ensure that it can be adjusted and rebuilt and to provide convenience for later maintenance work. Therefore, in the actual construction process, we can use the retarding time of the superplasticizer to blend with high-performance superplasticizers. If these two admixtures are affected by weather, their performance will decrease, mainly because they cannot be dissolved in other materials, so attention should be paid during construction.
TRUNNANO is a supplier of superplasticizer with over 12 years experience in nano-building energy conservation and nanotechnology development. It accepts 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 additives, please feel free to contact us and send an inquiry. (sales@cabr-concrete.com).
Early strength agents for concrete are a compound that may speed up the growth of strength in the beginning of concrete. Adding an appropriate amount of early strength agent to concrete can significantly shorten the curing cycle of concrete, improve construction efficiency, and enhance the frost resistance and durability of concrete.
Different early strength agents or the same early strength agent are added to different types of cement concrete, and their effects are not completely the same. Here, only a few early strength agents are taken as representatives to analyze their principles of action.
Chloride-based early strength agent: The main mechanism of action is the interaction between chloride and C3A in cement, generating insoluble hydrated chloroaluminates that can accelerate the hydration of C3A in cement. The calcium hydroxide that is formed through the hydration of chloride, as well as cement, creates calcium chloride that is insoluble, which reduces the level of calcium hydroxide present in liquid phases. It also speeds up the hydration rate of C3A, and the generated complex salt increases the volume of the solid phase in the cement slurry, forming an internal skeleton system, which is conducive to the formation of cement stone structure. At the same time, due to the fact that chlorides are mostly soluble salts, they have a salt effect. They can promote the dissolution rate of Portland cement clinker minerals and accelerate the hydration reaction process, thereby accelerating the hardening rate of concrete mixtures and improving the early strength of concrete.
Sulfate-based early strength agents, such as anhydrous sodium sulfate, dissolve in water and react with calcium hydroxide generated by cement hydration to produce calcium oxide and calcium sulfate. The newly generated calcium sulfate particles are extremely fine and have much higher activity than those doped with calcium sulfate, thus reacting with C3A to generate hydrated calcium sulfoaluminate at a much faster rate. Sodium hydroxide is an active agent that can improve the solubility of C3A and gypsum, accelerate the amount of calcium sulfoaluminate in cement, and lead to the hardening and early strength improvement of cement. However, sulfate early strength agents have a certain corrosive effect on the steel bars in concrete, including chloride early strength agents, and attenuate the later strength of cement mortar. Therefore, the dosage of chloride and sulfate early strength agents is gradually decreasing.
Impact on concrete mix
Early strength agents can generally shorten the setting time of concrete. Still, when the content of tricalcium aluminate in cement is low, or the content of tricalcium aluminate is lower than that of gypsum, sulfate will delay the setting time of cement. Early strength agents generally do not increase the air content in concrete. The air content of the water reducing agent determines the air content of early strength water reducing agents. If combined with sugar calcium water reducing agents, the air content does not increase, but when combined with wood calcium water reducing agents, the air content increases significantly.
Impact on concrete
Early strength agents can improve their early strength. The degree of improvement of the same type of early strength agent depends on its dosage, environmental temperature, curing conditions, W/C, and cement variety. The impact on the long-term strength of concrete is not consistent, ranging from high to low. Early strength agents have good effects within a reasonable dosage range, but when the dosage is large, it will have adverse effects on the later strength and durability of concrete. Early strength water reducing agents also have good early strength effects, and their performance is better than that of early strength agents, which can control the later strength changes. Triethanolamine can stimulate the early strength effect of cement, which can accelerate the hydration of tricalcium aluminate but delay the hydration of tricalcium silicate and dicalcium silicate. Excessive dosage can cause a decrease in concrete strength.
Durable sulfate based early strength agents have no corrosion effect on steel bars. Still, chloride early strength agents contain a large amount of chloride ions, which have a promoting effect on steel bar corrosion. When the dosage is large, it will also reduce the chemical corrosion resistance, wear resistance, freeze-thaw resistance, etc., of concrete, reduce the flexural strength of concrete, increase the early shrinkage of concrete, and have little impact on the later stage of concrete. At present, the use of admixtures containing chlorides is prohibited in the new national standard regulations. To prevent the impact of chloride salts on steel corrosion, rust inhibitors and chloride salts are often used in combination.
When using sulfate early strength agent, due to the increase in alkalinity in the concrete liquid phase, it should be noted that when the aggregate contains active silica, it will promote the reaction between alkali and aggregate, causing the problem of concrete damage due to alkaline expansion.
Triethanolamine will increase the shrinkage of concrete. When the dosage is greater than 0.05%, it will reduce the later strength, and the larger the dosage, the more it will decrease.
Early strength water reducing agent, due to its function as a water reducing agent, can compensate for the defects of early strength agent, change the microstructure of the inner pores of the concrete, improve its compactness, and thus improve the freeze-thaw resistance, admixture resistance, compression resistance, bending resistance, elastic modulus, and steel bar bonding of concrete. Within a reasonable dosage range, it has no adverse effect on steel bar corrosion, and early shrinkage slightly increases. It has been widely used in China.
A large number of tests have shown that sulfate series early strength agents can improve the impermeability of concrete.
The deformation: early strength agent generally has little effect on the deformation (dry shrinkage) of concrete.
Concrete early strength agents have been applied in many construction fields, and the following are several common application scenarios:
Low temperature environment construction: When conducting concrete construction in a low temperature environment with a daily minimum temperature of no less than minus 5 degrees Celsius, adding concrete early strength agent can accelerate the setting and solidification process of cement concrete, avoid freezing damage to cement concrete in colder environments, and accelerate the operation of formwork, improving work efficiency.
Rapid opening of road surface and bridge deck pavement layer: When constructing concrete for road surface or bridge deck pavement layer, especially on level crossings of Class 1, 2, and 3 highways, early strength agents can be added to accelerate the hardening process of concrete, enabling the road surface or bridge deck pavement layer to reach the opening conditions more quickly.
Rapid maintenance of concrete: For rapid maintenance of concrete pavement and bridges, the application of early strength agents can significantly shorten repair time and improve repair efficiency.
It is worth noting that for concrete with early strength requirements or steam curing, as well as concrete constructed with a daily minimum temperature below 5 ℃, it is generally not recommended to use early strength agents. Therefore, when using concrete early strength agents, it is necessary to select and add them based on specific construction conditions, requirements, and the properties of the concrete.
TRUNNANO is a supplier of early strength agents with over 12 years experience in nano-building energy conservation and nanotechnology development. It accepts 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 additives, please feel free to contact us and send an inquiry. (sales@cabr-concrete.com).
The main components of foam concrete are: cement, foaming agent, aggregate, fly ash, admixture and water. When necessary, other ingredients can be used according to requirements, such as chopped fibers and organic polymers, which all affect the strength of foam concrete.
For foam concrete, the importance of cement is self-evident. Cement is the main source of strength of foam concrete, which also determines the overall strength of concrete to a large extent. Therefore, in order to achieve maximum strength, there is an optimal cement content value for the dry density of foam concrete. This value exists in an ideal mix ratio, which can ensure that the concrete has sufficient strength without wasting materials.
It is worth noting that different blocks of cement have different effects on the strength of foam concrete due to their different raw materials and production processes. Therefore, the key step to producing high-quality foam concrete is to select the appropriate cement type and determine its dosage.
In the non-paste system, with the increase of cement content, the strength of foam concrete will increase until the optimal cement content is reached. Once this dosage is exceeded, the trend of strength increase will reverse and decrease with a further increase in cement dosage. The occurrence of this phenomenon may be due to the formation of pores inside the concrete due to excessive cement, which affects the overall strength of the concrete.
In the neat cement slurry system, because of the use of full water dilution, the cement consumption is relatively fixed, so in this system, changing the cement strength grade will have a significant impact on the strength of foam concrete. This requires special attention during the production process to prevent the improper selection of cement strength grade from affecting the quality of concrete.
Portland cement series products have stable quality, low price and good durability, so they are widely used in the current foam concrete industry. However, no matter what kind of cement is used, it is very important to know the cement amount and its mix proportion with foam. Only through reasonable proportioning and precise control can we produce high-quality foam concrete products.
Not all of the materials that can produce foam can be used as suitable foaming agents to prepare foam concrete. In order to ensure the quality and stability of foam concrete, the foaming agent must have some specific properties. Firstly, when mixed with mortar, it must not cause mortar cracking and maintain its stability. Secondly, the addition of foaming agents should not have a negative impact on the performance of bonding and hardening materials.
The density of foam concrete can be adjusted by changing the amount of foaming agent. With the increase in the amount of foaming agent, the density of foam concrete will decrease accordingly, and vice versa. This density change directly affects the strength of foam concrete. After the introduction of foam, the strength of concrete will be reduced due to the existence of a large number of pores. However, foam concrete with high strength and stability can be prepared by optimizing the amount of foaming agents and selecting appropriate raw materials.
In addition, the strength of foam concrete does not depend only on its density. The size, distribution, and stability of foam and the properties of the concrete matrix will also affect its strength. Therefore, when preparing foam concrete, these factors need to be comprehensively considered according to specific needs to obtain the optimal and most efficient preparation process.
The preparation of foam concrete aggregate is generally divided into three categories: ordinary aggregate, light aggregate and ultra-light aggregate. These aggregates play an important role in foam concrete, which can increase the strength, durability and stability of concrete.
Ordinary aggregate is a commonly used type of aggregate with high density and strength. It can improve the overall strength and compressive performance of foam concrete and help to improve the durability and stability of concrete.
Lightweight aggregate is another commonly used type of aggregate, with a lighter density and lower strength. It is mainly used to reduce the density of foam concrete and can also improve the thermal insulation and sound insulation performance of concrete. Light aggregate can make the structure of cement paste more compact, thus improving the overall strength and compressive performance of foam concrete.
Ultralight aggregate is a kind of aggregate with extremely low density and strength, which is usually used to prepare foam concrete with low density, high thermal insulation performance, and high sound insulation performance. Ultralight aggregate can improve many properties of foam concrete, such as heat preservation, sound insulation, compression resistance, and durability.
When preparing foam concrete, different types of aggregates need to be selected according to specific application scenarios and requirements. The strength of foam concrete is significantly affected by different aggregate types and apparent densities. In order to ensure the density and strength of foam concrete, the use of lightweight aggregate can make the structure of cement paste more compact than ordinary aggregate, thus improving the overall performance of foam concrete.
In view of its wide sources, low price, and certain activity, fly ash has become the preferred admixture for foam concrete admixtures. Fly ash can dramatically increase the strength of concrete that has been foamed and increase its forming ability.
The common admixtures used in foam concrete are dispersants and early strength agents, rapid curing agents, water-proofing agents, and water repellent agents. Accelerators and early strength agents are able to accelerate the process of formation and strengthen the foam concrete structures, as well as enhance the durability of the structure of the slurry.
TRUNNANO is a supplier of foam agents with over 12 years experience in nano-building energy conservation and nanotechnology development. It accepts 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 additives, please feel free to contact us and send an inquiry. (sales@cabr-concrete.com).
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