Terrazzo floor tiles are relatively common building decoration materials at present. Because terrazzo is rich in raw materials, the price is much lower than other floor materials, the construction process is simple, and the decorative effect is good, it has been widely used.
The investigation of the cause of cracks includes the investigation of materials and construction quality, design calculation and structure, use environment and load, etc., which provides the basis for crack analysis.
It is determined whether it is a structural crack or a non-structural crack through the observation of the current status of the crack and the investigation of the cause of formation.
A crack whose width and length remain constant is a stable crack. As long as its width is not large and meets the requirements of the code, it is less dangerous and belongs to a safe component.
The width and length of the cracks continue to expand with time, indicating that the stress of the steel bar may approach or reach the flow limit, which will have a serious impact on the bearing capacity, and measures should be taken in time.
4. Crack detection
Crack detection is the status inspection of cracks. Through the current status detection and the drawing of crack distribution maps, it provides a basis for crack analysis and hazard assessment.
Commonly used instruments for crack appearance detection include scale magnifying glass, crack comparison card, etc. The crack depth is mainly detected by ultrasonic method or direct core drilling method. The general steps of detection are as follows:
01 Drawing crack distribution map
First draw the shape of the cracked component, then mark the position and length of the crack on the drawing, and number each crack and indicate the time when the crack appeared.
For the convenience of research and analysis on the terrazzo floor, the crack map should be drawn one by one according to the components, and the orientation should be marked on the map. When there are many cracks, you can draw a grid on the surface of the component with cracks. The size of the grid should be 200~500mm according to the size of the component. Draw a line along the crack with a brush or chalk on one side of the crack, and then use the same Copy the position to the record book, and take photos and videos for cracks with special shapes.
02 Determination of crack width
When measuring, divide the total length of the crack into four equal parts, the central point and the two ends, and the central point and the third point in the middle. To measure the vertical width in the direction of the crack, use a special microscope with a scale, place the scale perpendicular to the crack, measure the width of the crack, record the reading and mark it on the graph.
You can also use the crack card to estimate the crack width through a magnifying glass, but this method has a large error. The length of the crack can be measured with a steel ruler, and there should be a mark at the end of the crack, and the year, month and day should be marked to observe the development of the crack.
When measuring the length and width of cracks, the thickness of the protective layer must be confirmed at the same time. When the concrete thickness of the protective layer is not suitable for chiseling, the steel detector can be used to find out its thickness.
