After the construction of acid resistant castable, cracks will appear. What is the reason for this?
The construction period is just hot summer, and the construction of refractory castables in summer is a great test of the construction personnel's technology. Due to the large temperature difference between day and night, the main performance is that half of the chimney is exposed to the sun in the first half of the day, and the other half is exposed to the sun in the second half of the day. In this way, the heating degree of the cylinder is not the same, and the expansion and contraction caused by the temperature difference are not consistent, but the cracks caused by the temperature difference stress are usually the same There's no order, no regularity.
Light acid resistant castable is mainly composed of lightweight aggregate, binder and additives. The binder is mainly composed of water glass, and the aggregate has high water absorption and hygroscopicity. The natural dehydration phenomenon during the solidification process of castable will inevitably produce shrinkage stress. However, after demoulding, the cutting treatment of 1500 × 1500mm square seam width 2.5 ~ 3mm depth 25mm has been carried out, and the structure is round cylinder, The cracks caused by shrinkage stress are usually vertical distribution, and should appear in large area and small size.
Light acid resistant castables are mostly used in petrochemical system, and they are all used in the northern region where the climate is relatively dry, and the structure is generally not very high. This is the first time that it has been used in the southern region where there is much rain and high humidity. It is also the first time that it has been used in the thermal power plant with desulfurization treatment, and it is also the first time that it has been used in the chimney with a height of 240 meters. During the construction and storage period, there is more rain, higher air humidity, poor construction environment and narrow working site. The construction temperature of the material should be 5 ℃ ~ 30 ℃. When the temperature is lower than 5 ℃ or higher than 30 ℃, the construction can only be carried out after the mix proportion is adjusted by the on-site technician of the manufacturer. In summer and autumn, most of the ambient temperature fluctuates around 30 ℃, and the temperature difference is large, so the mix proportion needs to be adjusted frequently
