混凝土空气仪表和指示器

空气仪表及指示器

Controlling the air content through air entertainment is essential in many types of concrete. 与一个 加气仪, small, uniform air bubbles are deliberately created within a concrete mixture. 这些气泡在0之间.1mm 和 1mm in diameter 和 protect concrete exposed to freezing 和 thawing from damages caused by freezing water. By serving as air voids in the hardened concrete, the bubbles relieve pressure without causing damage 和 thus extend a mix’s lifetime.

The Importance of Air Content Testing
Air meters 和 indicators are used to determine the air content of fresh concrete at the point of placement. 因为混合, 运输, pumping 和 h和ling a mix can take out valuable air bubbles, the final air content of concrete must be tested at the right time 和 place. Therefore, mix evaluations throughout the settling process is essential. A complete air content reading guarantees that the concrete will be durable under freeze/thaw conditions when insitu.

Even concrete that is not exposed to freeze/thaw conditions is often tested for air content. While non-air-entrained mixes contain air contents between 1% 和 2%, concrete with more than 3% entrapped air is prone to surface defects 和 delamination. 正因为如此, air content testing can locate issues before they occur 和 is valuable for a complete mix analysis.

There are multiple air content testing methods, all of which provide valuable information about a concrete sample 和 its workability. While many variations, there are three main practices of air content testing:

1. The Pressure Method for Air Content 利用 气压计 提供快速、可靠的结果. Using an upper chamber of air 和 a lower chamber of concrete, air is pressurized 和 released into the lower chamber. The bubbles formed by the concrete compressing under increased pressure are measured 和 used to determine the air content of the concrete. This method is best for lightweight or normal-weight concrete mixes.

2. The Volumetric Method for Air Content 而不是使用 容积式空气计 or roll-a-meters. This practice takes significantly more time 和 effort but can be used for all concrete mixes. 用这种方法, a specimen is filled with both water 和 isopropyl alcohol until the air voids are effectively washed out of the mix. The difference in fluid levels before 和 after the procedure is recorded as the air content of the concrete mix.

3. 重量法 involves a wide range of equipment including 单位重量计量, 捣固棒 和 花样的盘子. Using the specimen weight 和 actual batch weights, calculations are executed to determine concrete air content 和 many other properties of the mix. Because slight variations can cause relatively large errors, this method is best for trial mix designs.

Since there are multiple ways to test air content of fresh concrete, you have to be careful not to only go by the initial results. Assessment outcomes can vary especially based on conditions. Specifically on large quantities of concrete, it can be important to do further investigation with both field 和 lab tests.

洪堡 provides a wide selection of 空气仪表及指示器 to choose from. If you have questions or need help selecting equipment, please call us at 1.800.544.7220或使用我们的 问问洪堡表格.