01.Causes of cracks in lightweight acid-resistant castables
During construction, if there is a large temperature difference on site, the cylinder lining will be heated unevenly, and the temperature difference will cause different expansion coefficients. The temperature difference stress will cause cracks, and one side will solidify and the other side will not solidify.
When constructing lightweight and resistant castables, the added binder will also cause dehydration during solidification, causing the cast body to shrink. This shrinkage stress will cause vertical cracks, sometimes in large areas. The amount of binder added , will also cause cracks in lightweight acid-resistant castables. The operator adds more binder when stirring, so that the castable cannot condense on time, and cracks will appear after baking.
If the construction is in an area with high rainfall and humidity, and the construction temperature is not kept within the range of 5-30°C on-site, the condensation speed will also be slow, and network cracks will appear later. Another situation is that premature removal of the formwork causes vertical cracks. Vertical cracks affect the service life of the lining.
When the above situations occur, unstable factors must be fully controlled. The first thing is to control the amount of binder added, and then ensure that the ambient temperature and weather changes are handled in a timely manner so that the temperature is suitable for construction. In particular, the time for removing the formwork must be mastered. The formwork cannot be removed until the castables solidify.
02.Function
Lightweight acid-resistant castables are semi-light materials that function as both thermal insulation and resistant to acid gas erosion. The most important thing is the treatment of expansion joints. During construction, reserved expansion joints must be cut, and must not be cut into through joints, because through joints will cause corrosion damage to the reinforced concrete outer cylinder. In addition, the steel bars in the castables should be coated with epoxy paint to prevent Anti-corrosion.