Views:6 Author:YEYANG STONE GROUP. Publish Time: 2020-08-24 Origin:marble-guide.com
Construction technology improvement and quality control of natural marble
Natural marble is widely used in modern construction projects for its elegance, luxury, wear resistance and corrosion resistance. Paying attention to the causes of common quality defects of natural marble and its quality control, and improving construction technology are practical and theoretical issues in project quality management.
1 Common quality defects and causes of marble material installation and construction technology
1.1 Marble wall hollow drum falling off
The main reasons for this phenomenon are water seepage and insufficient grouting at the base or substrate; on the other hand, because marble contains CaCO3 and various mineral materials and other impurities, long-term wind, frost, rain, snow and sun will cause its discoloration and fading.
The CaCO3 in the marble meets with the acids in the air and chemically reacts to produce gypsum that is easily soluble in water, making the surface dull and rough, causing pitting, cracking and shedding.
1.2 The joints of the board are not straight, and the texture of the board is not smooth
The main reasons are improper processing of the base layer or substrate, with partial uneven surfaces; the finished plates have not been strictly selected, the colors are different, the specifications are not correct, there are cracks, pollution and damage; the number is not tried before the installation and construction; the layered grouting height is too high; Improper construction sequence, etc.
1.3 Marble veneer cracking
The main reason is that when marble slabs are mounted on external walls or close to wet spaces such as kitchens and bathrooms, the installation is rough, the grouting of the plate joints is not strict, and the corrosive and damp gas penetrates into the plate joints, causing the metal connectors to rust and expand, and the marble slab is affected. Deformation thrust and crack;
When the color pattern of the marble slab is dark seam or other hidden defects, the stress concentration is generated due to the settlement of the structure, which causes the weak part of the stone to crack; when the vertical veneer is vertical, the upper and lower gaps are small, the structure is deformed under pressure, and the plate is cracked under vertical pressure.
1.4 Marble veneer damage and pollution
The main problem of on-site management is improper operation during the transportation and storage of the boards; the residual mortar was not immediately removed during the construction process; the construction site protection work was not done after the installation.
2 Preparations for construction and installation of natural marble materials
2.1 Mounting preparation
First, check the actual deviation of the structure according to the design drawings, check the vertical flatness of the base wall, pick or repair the parts with large deviation; secondly, determine the actual height of the column and the center line of the column for the column surface construction. The upper, middle and lower horizontal lines determine the size of the veneer panel;
For the one-sided side of the staircase wall skirt and the complicated shape, the side should be solid first, and other materials should be used to proofread the large size sample if necessary. Finally, check the measured specifications and dimensions according to the wall pillars, and calculate the width of the joints between the veneers, calculate the stalls of the panels, number them in the order of installation, and draw the large sample diagrams of the blocks and nodes as a basis for processing orders.
2.2 Installation surface treatment and line leveling
First of all, it is required that the construction substrate or base layer has sufficient stability and rigidity, so that the surface is flat but rough. The smooth surface should be roughened first. The depth of the chiseling is 5~15mm, and the spacing is >15mm; the surface of the substrate or base layer has mortar. Residues such as dust, oil stains, etc. must be removed with a wire brush and then rinsed with water. When the columns are inlaid with marble materials, the center line of the column and the elevation line of the horizontal line should be popped up according to the size of the axis of the building as a leveling datum.
2.3 Stone inspection and numbering
After the stone is unpacked, strictly select the varieties, specifications, color and luster without missing edges. Sheets with corners; then try to assemble according to the design size, set the square edge, check the flatness, measure the verticality of the corners, and make the size meet the design requirements, and control the inlay The actual size after pasting should ensure the same width and height; the color change should be natural, and the same wall or facade should be unified.
When matching the pattern, try to make the top, bottom, left and right to be smooth, the texture is natural, the same surface pattern should be symmetrical, so as to be a seamless one; when pre-numbering, for the mounting part, the stone should be strictly selected, and the texture and color should be good. Used in the main space.
3 Improvement of natural marble construction
Yi’s traditional natural marble paving process is to pre-hang the steel mesh and lead wire on the base layer and then pour the mortar. This kind of process is cumbersome, complicated to operate, and costly. Due to improper control in engineering, quality problems such as weak adhesion and uneven surface are often caused.
Improved technology is a new construction technology based on absorbing foreign advanced technology and combining the advantages of traditional technology. The method of preparing the plate number and matching the pattern for the construction of this process is basically the same as the traditional process. The other technical points are:
3.1 Matrix treatment
First, moisten the cleaned substrate with water, spread 1:1 cement mortar, use coarse sand or medium sand, and scrub the back of the stone with water to enhance the adhesion;
3.2 Plate drilling
Use an electric drill to drill holes at 1/4 side length from both ends of the plate, with a depth of 35-40mm and a diameter of 6mm. When the board width is ≤500mm, the number of holes is 2; when the board width>500mm, the number of holes is 3;
When the board width>800mm, the number of holes is 4. Then drill a straight hole on each side of the board. The hole is located 100mm from the lower end of the board, the hole diameter is 6mm, and the hole depth is 35~40mm. The length and width of the upper and lower straight holes should be not less than 70cm and 30cm, and the distance from the edge of the board should not be less than 70cm. Less than 100cm, the slotting form and plane position are shown in Figure 1.
In order to make the new and old concrete tightly combined, the slotted interface is chiseled and cleaned, and the steel fiber is coagulated. The soil can be increased by a mark, that is, C35 extra-fine sand steel fiber concrete is used.
3.3 through cracks
This kind of cracks are mostly structural stress cracks. Before repairing, it is necessary to determine whether the roadbed and the base layer are stable. Only after the foundation reaches sufficient stability can the repair be carried out.
The form of grooving is mostly through-grooving or refurbishment of the whole board. After repeated trials, alloy chisel is used to pick grooves on the back with alloy chisel, the groove depth is 6-8mm, so that the U-shaped nails can be installed.
3.3 Matrix drilling
After the plate is drilled, it is laid out and divided into blocks according to the base body, and temporarily placed in place. At the position of the corresponding base body with the upper and lower straight holes of the plate, drill an oblique hole equal to the number of holes of the plate with an electric impact drill. The hole is inclined at 45°, the hole diameter is 6mm, and the hole depth is 40-50mm.
3.4 Plate installation and fixing
3.4.1 According to the hole distance between the plate and the substrate, use wire pliers to first put a stainless steel ∪-shaped nail with a diameter of 5mm in the straight hole of the plate and use a hardwood wedge; put the other end into the oblique hole of the substrate. The surface is vertical, flatness and the upper and lower openings on the board, and correct the tightness of the joint with the adjacent plates, and wedge the stainless steel ∪-shaped nails. Then use a big wooden wedge to fasten between the plate and the base to fasten the U-shaped nails.
3.4.2 Correct the position of the board accurately, fix it temporarily, and then grouting in layers. There should be no bumps before the mortar sets.
4 Quality control of common quality problems in natural marble construction
4.1 Quality control of marble veneer hollow drum falling off
Carefully handle the top position of the outdoor marble finish to ensure that the base layer does not penetrate water, especially the horizontal joints. In the design, add a rain cover as much as possible on the upper part to prevent direct exposure to rain and sun, and shorten the service life; the stone used for the exterior surface should be made of pure quality materials with less impurities, weathering and corrosion resistance.
4.2 Quality control of uneven seams and uneven surface texture
Make rules for the elastic line at the grassroots level, and divide the bins into compartments, pop up the center line and horizontal line on the larger surface, and pop up the marble wall line; check the flatness of the grassroots plane before installation, and pick up in advance if the deviation is large Or repair, so that the distance between the base layer and the surface of the board is not less than 50mm, and the cleaning is clean, and the water is soaked; the boards with missing edges, corners, cracks and local pollution and discoloration are picked out in advance, and the package inspection is carried out.
The slabs with size deviations should be edging correction; according to the elastic line of the wall to find the gauge distance for trial assembly, the color is adjusted, the pattern is adjusted to make the top, bottom, left, and right textures between the board and the board smooth, and the color is coordinated; small-size boards are pasted Method, when the large-size board or the mounting height exceeds 1m, a stronger installation process must be adopted; after the gypsum slurry is solidified, use 1:2.5 cement mortar to pour in layers, and the height of each infusion should not be too high. Otherwise, it is easy to make the board. Expansion moves outward, affecting the smoothness of the finish
4.3 Quality control of marble wall cracking
The gap between the joints of the plates should not be greater than 0.5~1mm, so that the joints are tight, the grouting is full, and the plates must not have defects such as cracks, missing edges, corners, etc., to prevent corrosive gas and humid air from intruding, rusting embedded metal components and causing plate cracks ;
When inlaid with marble veneer on the surface of load-bearing members such as wall pillars, it is necessary to wait for the settlement of the structure to stabilize before proceeding. When the marble veneer is installed on the top and bottom, a certain gap is left to prevent the veneer from being crushed and cracked due to the direct load-bearing of the structure compression.
4.4 Quality control of collision damage and pollution of marble finishes
There are certain gaps and dyeing ability between the marble particles, which will penetrate and absorb when encountering colored liquids, and it is not easy to remove the marble surface after it is contaminated.
Therefore, in the process of transportation and storage, light-colored marble decorative panels should not be tied with straw ropes and curtains. It is not advisable to stick colored packaging to protect the finished product in the process of protecting the finished product to prevent it from being polluted by colored liquids after being exposed to water.
During construction grouting, the joints are required to be straight and tight. Fill the horizontal and vertical joints with hemp or use hemp ash to prevent the joints from leaking and causing pollution; the marble is delicate, so it is stacked and transported . Careful protection during the process.
When the marble veneer is moved upright and the corners are on the ground, avoid the front corner or the corner first to prevent the front corners from being damaged and affecting the tight joints of the joints. Large-size plates should not be transported flat, otherwise it will aggravate the hidden damage or rupture of dark seams and semi-penetrating seams due to the expansion of the bending moment generated by the weight of the stone;
After the marble is installed, the protection of the construction site should be done carefully. The internal corners such as the cylindrical doors, windows and sills should be firmly tied with wooden boards, and the walls should be covered with wooden plastic film. When installing the stair steps, use wooden boards for every step. protection