As a beautiful, durable and economical floor decoration material, cast-in-place terrazzo is widely used in commercial buildings, hospitals, schools and other places. Its construction process is relatively complicated, but strict compliance with the specifications can ensure the construction quality and decorative effect. The following is a complete article about the construction process of cast-in-place terrazzo.
1. Construction preparation
Before construction begins, adequate preparations need to be made. This includes selecting qualified materials, determining construction plans, and performing base treatment.
①Material selection:
·Cement: Use ordinary silicate cement or silicate cement with a strength grade of not less than 425. Colored terrazzo should use white or colored cement.
·Gravel: Use clean marble particles without debris, the particle size is generally 4-12mm, and different specifications and colors of stones can be selected according to design requirements.
·Sand: Use medium sand, pass through a sieve with a pore size of 0.63mm, and the mud content shall not exceed 3%.
·Pigment: Use alkali-resistant and light-resistant mineral pigments, and the color should be consistent with the design requirements.
·Divider strips: Generally use copper strips, glass strips or plastic strips, and the specifications should meet the design requirements.
·Other materials: Including auxiliary materials such as oxalic acid, floor wax, and cement slurry.
②Construction plan: According to the design drawings and the actual situation on site, determine the construction thickness, style size, and divider strip arrangement.
③Base treatment: Clean the floor or wall, remove the mortar skin and ash layer, and sweep it with a broom. For oily bases, use 10% caustic soda water to brush and rinse with clean water. Then sprinkle water to moisten the base, and brush a layer of plain cement slurry with a water-cement ratio of 0.4-0.5.
2. Construction of leveling layer
The leveling layer is the foundation of cast-in-place terrazzo floor, and its flatness and firmness are crucial to subsequent construction.
①Marking lines to find rules: According to the design requirements, vertical and horizontal or pattern ink lines are drawn on the wall or floor to determine the position of the dividing strip and the flatness of the floor.
②Spreading leveling layer mortar: 1:3 cement mortar is used as the leveling layer material with a thickness of 20-30mm. First spread the mortar flat, then use a pressure ruler to scrape it flat on the ribs, and then use a wooden trowel to smooth and compact it. The surface is required to be flat and dense, and remain rough, so that it can be firmly combined with the surface layer.
③Maintenance: After the leveling layer is applied, it should be watered and maintained for at least one day, and it is best to maintain it for 2-3 days before proceeding to the next process.
3. Inlay of Dividing Strips
Dividing strips are used to divide the terrazzo floor into several small pieces to improve the stability and aesthetics of the floor.
①Drawing dividing lines: Draw dividing lines on the leveling layer according to the design requirements, and the spacing is generally about 1m.
②Inlaying dividing strips: Use pure cement slurry to apply an eight-shaped angle to the lower part of the dividing strip and embed it firmly (at an angle of about 30 degrees to the leveling layer). The dividing strips should be firmly embedded, the joints should be tight, and the top surface should be on the same horizontal plane.
4. Spread the surface stone slurry
The surface stone slurry is the key part of the cast-in-place terrazzo floor. Its quality and construction skills directly affect the appearance and durability of the floor.
①Mixing stone slurry: dry-mix cement, gravel, pigment and other materials according to the design ratio, then gradually add water and stir evenly, so that the mixture can be held in a ball and fall apart when released.
②Spreading stone slurry: spread the mixed material evenly in the dividing strip, compact and smooth it with an iron trowel until it is flush with the dividing strip. During the laying process, care should be taken to avoid the dividing strip from being touched.
③Rolling and smoothing: roll the mixed material with a roller until the surface is slurry, then smooth it with a wooden trowel, and then smooth and compact it with an iron trowel.
5. Maintenance and polishing
Maintenance and polishing are important links in the construction of cast-in-place terrazzo floors, and have a decisive influence on the flatness and smoothness of the floor.
①Maintenance: After the stone slurry is spread, watering and maintenance should be carried out from the next day. The ground should be kept moist during maintenance to avoid cracking.
②Trial grinding: Trial grinding is carried out after the surface layer has been cured for 2 to 3 days. The purpose of trial grinding is to check the flatness of the surface layer and the exposure of the stones. If there are any problems, make adjustments in time.
③Polishing: The polishing operation should be carried out using the "two slurries and three grinds" method. That is, first use a 60-80 coarse grinding wheel for rough grinding to grind off the cement slurry of the surface layer to expose the stones; then use a 100-150 grinding wheel for the second grinding; finally, use a 180-240 fine grinding wheel for the third grinding until the surface is smooth and flat without sand holes and fine pores. After each grinding, rinse with clean water and apply the same color cement slurry for grouting and maintenance.
6. Apply oxalic acid to polish and wax and polish
①Apply oxalic acid to polish: Apply 10% to 15% oxalic acid solution to the ground terrazzo surface to clean and polish. During operation, you can apply oxalic acid solution or directly pour a proper amount of water and sprinkle oxalic acid powder on the terrazzo surface, and then grind it with fine oilstone until white slurry is produced and the surface is smooth.
②Wax and polish: Wax and polish after the floor is dry. Apply floor wax on the floor and then wipe it with a waxing machine or cloth mop until the floor is as bright as a mirror.
7.Construction precautions and quality standards
①Construction precautions:
·During the construction process, the material ratio and construction quality should be strictly controlled.
·Avoid uneven exposure of stones, hollowing of the four corners of the grid blocks and other common engineering quality problems.
·Do a good job of protecting the finished products to avoid heavy objects hitting and contaminating the ground.
②Quality standards:
·The material, strength (mix ratio) and density of the surface layer must meet the design requirements and construction specifications.
·The surface layer must be firmly bonded to the base layer without hollowing.
·The surface of the terrazzo surface layer should be smooth without cracks, sand holes and grinding patterns. The stone particles should be dense and uniform, and the color pattern should be consistent and not mixed.
8. Conclusion：
Although the construction process of cast-in-place terrazzo floor is complicated, strict compliance with the specifications can ensure the construction quality and decorative effect. During the construction process, attention should be paid to the details of each link to ensure the flatness, smoothness and beauty of the terrazzo floor. At the same time, good protection of the finished product is also an important part of ensuring the construction quality. With the advancement of technology and materials, cast-in-place terrazzo will have more innovative applications and development prospects.
