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 |
Paint rollers
The ability to store paint, and consequently the performance of the painting struggle.
Various factors decide about it, of which the most important is:
1) roller width,
2) shaft circumference,
3) roller cover type,
4) hair height.
The materials most often used as a roller coating …
Buildings of the ZL category
According to the division of buildings according to their purpose and method of use, residential buildings, collective residence and public utility buildings as well as parts of buildings constituting separate fire zones, is characterized by the appropriate risk category for humans, referred to as ZL:
1) ZL I …
In the specialist trade, carpet tiles of various qualities are offered, structure, surfaces and shades – the selection depends on their application (residential area, wet room, e.t.c.). The size of the tiles is 50 x 50 cm or 40 x 40 cm. Tiles …