There are many factors affecting the strength of concrete, which can be summarized as follows: material composition, preparation methods, curing conditions and test conditions.

Influence of materials on concrete strength:

1. The strength and water cement ratio of cement mainly depend on the quality of cement paste that plays the role of cementation inside, and the quality of cement paste depends on the characteristics of cement and water cement ratio.

2. The characteristics of aggregates have obvious influence on the strength of concrete, and the shape and surface properties of coarse aggregates have direct influence on the strength.

3. The slurry aggregate ratio also has a certain impact on the strength of concrete. Under the same water cement ratio, when the optimal slurry aggregate ratio is reached, Autoclaved aerated concrete blocks The strength decreases with the increase of slurry aggregate ratio.

Influence of curing conditions on concrete strength: humidity, temperature, age.

Influence of test conditions on concrete strength: the test conditions that affect the mechanical strength of concrete include: the shape and size of the test piece, the humidity of the test piece, the temperature of the test piece, the support conditions and the loading method.

The purpose of curing is to create appropriate temperature and humidity conditions to ensure or accelerate the normal hardening of concrete. Different curing methods have different effects on concrete performance. Common curing methods include natural curing, steam curing, dry wet heat curing, autoclave curing, electric heating curing, infrared curing and solar energy curing. The time of curing is called curing cycle. In order to facilitate comparison, it is stipulated that the test pieces for determining concrete performance must be cured under standard conditions. The standard curing conditions adopted in China are: Level I horizontal control temperature is 20 ± 2 ° C, Level II horizontal control temperature is 20 ± 5 ° C, and the standard curing time is 28 days; The humidity shall not be less than 95%.

Measures taken to improve the strength of cement concrete:

1. High strength cement and early strength cement shall be selected.

2. Low water cement ratio and slurry aggregate ratio shall be adopted.

3. The mixing amount of concrete admixture.

4. Wet heat treatment: steam curing and autoclave curing.

5. Mechanical mixing and vibration shall be adopted.