Concrete admixtures are chemical substances added during the mixing process of concrete aimed at improving the physical, chemical, or mechanical properties of concrete. These admixtures can enhance the strength, durability, flowability, and impermeability of concrete to meet the needs of specific engineering projects.
Concrete admixtures are mainly divided into the following categories:
Improving flowability: Such as air entraining agents, water reducing agents, pumping agents, etc., which can maintain good workability of concrete while reducing water consumption and improving flowability.
Adjusting the setting time and hardening speed：Such as retarders, accelerators, etc., can control the initial and final setting time of concrete to meet the construction needs in different environments.
Improving durability: Such as waterproofing agents, antifreeze agents, impermeable agents, etc. These admixtures can enhance the frost resistance, impermeability, corrosion resistance, and other properties of concrete, extending the service life of the structure.
Enhance mechanical properties: Such as early strength agents, reinforcing agents, etc., which can improve the early strength of concrete to meet the high requirements for structural strength in engineering.
The main functions of concrete admixtures are as follows:
Improving the mix ratio of concrete: By reducing water consumption and increasing orthopedic content, the strength and durability of concrete can be improved.
Enhance the physical properties of concrete：such as impermeability, frost resistance, crack resistance, etc., to improve the durability and service life of concrete.
Adjusting the hardening rate of concrete: By adding retarders or accelerators, it can adapt to different construction environments and requirements.
Improving the construction performance of concrete: Air entraining agents and pumping agents can improve the pumping performance of concrete and facilitate construction operations.
Enhancing the mechanical properties of concrete: early strength agents and reinforcing agents can improve the early strength and durable strength of concrete.
Concrete admixtures are widely used in various civil engineering projects, such as buildings, bridges, tunnels, roads, etc. Its application areas include:
Building structure: A large amount of concrete admixtures are used in the beams, slabs, columns and other structures of buildings to improve the strength, durability, and impermeability of concrete.
Bridge engineering: In bridge construction, admixtures can improve the performance of concrete and increase the bearing capacity and service life of bridges.
Tunnel engineering: In tunnel construction, the use of admixtures can improve the impermeability and durability of concrete, ensuring the long-term stability and safety of the tunnel.
Road engineering: In road construction, admixtures can improve the crack resistance and wear resistance of concrete and extend the service life of roads.
Other fields: In addition to the fields above, concrete admixtures are also widely used in water conservancy engineering, port engineering, and other fields, providing efficient, energy-saving, and environmentally friendly building material solutions for various civil engineering projects.
Because the quality of commonly used raw materials for ready-mixed concrete fluctuates greatly, it is impossible to ensure smooth production and manufacturing. Therefore, adjusting the mortar mix ratio is indispensable and crucial. The adjustment method of mortar mix proportion during the processing process should be formulated based on the trial results to ensure that it is carried out within the controllable range, and authorized and professional training should be provided to relevant staff to enable authorized personnel to fully grasp the adjustment technology within the scope of management authority. Otherwise, mindlessly following the trend to adjust the mortar mix ratio will inevitably lead to deepening fluctuations in the quality of concrete, which can easily lead to product quality problems or safety accidents.
Generally speaking, admixtures have no special requirements for concrete mix proportions and can be designed using ordinary methods. However, in the case of reducing the water or saving cement, appropriate adjustments should be made to the sand rate, cement dosage, water cement ratio, etc.
1. Sand rate
The sand content has a significant impact on the workability of concrete. Due to the significant improvement in workability after the addition of water reducing agents, the sand content can be appropriately reduced by 1% -4%. For example, the lower limit for wood calcium can be 1% -2%, and the upper limit of air entraining water reducing agents can be 3% -4%. If the sand rate is too high, the reduction can be increased because high sand rates not only affect the strength of concrete but also bring certain difficulties to the molding operation. The specific ratio should be determined by the trial results.
2. Cement dosage
The use of water reducing agents in concrete has varying degrees of cement saving effects. The use of ordinary water reducing agents can save 5% -10%, while efficient water reducing agents can save 10% -15%. Using high-strength grade cement to prepare concrete and adding water reducing agents can save more cement.
3. Water cement ratio
The water cement ratio of concrete with water reducing agents should be determined based on the water reducing rate of the added variety. Originally, the water reduction rate was higher for those with a higher water cement ratio than for those with a lower water cement ratio. After saving cement, in order to maintain the same slump, the water cement ratio is the same or increased by about 0.01-0.03 compared to when no cement is saved.
TRUNNANO is a supplier of concrete admixtures 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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