News information

Concrete admixture: the following talk about some knowledge of concrete

Release time:

2022-01-12

Source:

Three main parameters of concrete

In concrete design, that is, to determine the proportional relationship between the amount of cement, water, sand and stone, the key three main parameters are: water-binder ratio, water consumption and sand ratio, clear the standard of the main parameters: on the basis of considering the strength and performance of concrete, clear the water-binder ratio of concrete, on the basis of considering the concrete pouring provisions of the cohesion, according to the type and specification of rough stone clear unit water consumption; the sand rate should be defined by the standard of slightly appropriate placement after filling the gravel gap with the total amount of sand in the stone. These three main parameters are closely related to the characteristics of concrete, such as the water-binder ratio is related to the strength and performance of concrete, the water consumption is related to the fluidity of concrete, and the sand ratio is closely related to the adhesion and water solubility of concrete.

Whether it is to calculate the mix ratio, or trial mix ratio, can not determine whether the configuration of concrete compressive strength is in line with the requirements, the purpose of the concrete strength test is to compare the three different water-cement ratio, to obtain the combination ratio that can meet the requirements of the compressive strength, and whether the amount of admixture used is economical and effective. Since the strength test of concrete is carried out after the concrete mix ratio is adjusted properly, in the compressive strength test, the characteristics of concrete mixtures with three different water-binder ratios should remain unchanged, I .e. the water consumption for maintenance should remain unchanged, the amount of admixture used should increase and decrease, the sand ratio should decrease and increase, and the amount of concrete admixture should also be adjusted or increased.

When the characteristics of raw materials fluctuate, the concrete mix proportion should be adjusted immediately. The expansion of water consumption of admixture and stone, and the reduction of water reduction rate of concrete admixture all lead to insufficient unilateral water consumption. The appropriate method is to increase the content of concrete admixture moderately, so that the unilateral water consumption does not exceed the clear concrete mix proportion, the water-binder ratio does not change, and the strength of concrete is guaranteed.

The size of the sand ratio has a key impact on the workability of concrete. Generally, with the increase of sand ratio, the cohesiveness of concrete increases first and then decreases, and there is a good sand ratio. When the specific sand ratio is less than the good sand ratio, the void ratio of the mixed stone composed of sand and stone is very large, and more slurry must be used to fill the gap. The slurry wrapped in the stone surface is thinner and the cohesiveness is poor, but when the sand ratio exceeds the good sand ratio, the use of fine stone sand is too much, resulting in an increase in bulk density, and the void ratio also exceeds the good void ratio, which also leads to the softening of the slurry wrapped in the stone surface layer, and the bonding of concrete becomes poor. In production practice, the sand ratio can be appropriately adjusted according to actual activities.

Water consumption directly affects the water-binder ratio, thus affecting the compressive strength, cracks caused by excessive water consumption, honeycomb, pitting and other problems will reduce the durability of concrete.

Key words:

None

Concrete admixture manufacturers talk about the following factors of insufficient concrete strength

All