Old substrates
What damage to the old coating, constituting the foundation of the new one, must be checked before reworking it?
Before applying a new coating, the following should be checked for damage to the old coating:
1) Dirty;
2) discoloration, fungus, pubescence;
3) calcification;
4) insufficient …
Zinc and galvanized steel
What types of galvanization are there?? What is the usual thickness of the zinc coating?
Most often, types of galvanization and standard thickness of the zinc coating layer are as follows:
| A type of galvanization | Coating thickness |
| Hot dip galvanizing | on single items 50-80 μm; already |
Cast iron and steel
What is the difference between steel and cast iron?
Steel contains less than 1,7% coal, while in cast iron it is 2-4% coal. The carbon content in the cast steel is 1,7-2,0%. Compressive strength and hardness increase with increasing carbon content, decreases …
Fiber-reinforced cement boards
It is planned to make the coating on the facade with fiber-reinforced cement panels. What technical conditions must be met in order to obtain a durable and defect-free coating?
Fiber-reinforced cement boards must be protected against underside moisture. …
What are the required substrate tests for aerated concrete prior to coating?? How defects and damage can be recognized?
The following substrate tests and damage identification are required:
| Subject of the study | Test method | Diagnosis |
| Moisture | visual | darker color |
| The presence of loose fit, brittle parts on |
To unambiguously determine the condition of the concrete surface, the degrees of surface damage are formulated from 1 do 5.
Degree 1. The concrete does not show any defects or damage, but should be protected against reduction in alkaline pH. The pores and cavities of the crayfish should be closed. Color of concrete …
Concrete
What raw materials is concrete made of?
Concrete is a mixture of cement, water and filler (aggregates). In order to obtain the special properties of special concretes, special additives and admixtures are introduced into the concrete mix.
What varieties of concrete are distinguished, depending on its density? …
The alkalinity of the plaster is due to the presence of calcium hydroxide in it (lime lye). The decisive factor here is the water-soluble calcium hydroxide content.
What damage may occur then, when the outer shell is less permeable to water vapor, than masonry and plaster?
It may happen …
Types of mortars (wg DIN)
The following types of mortars are distinguished:
| Type of mortar (the ground) | Application | Minimum compressive strength |
| Pla and Plb Air-hardening lime mortar and water-hardening lime mortar | only for low mechanical loads | no requirements |
| Pic |