1. Scope of application:
Due to the uneven dry and wet changes of buildings, thermal expansion and contraction, structural settlement and imperfection in design and construction, almost all buildings have surface capillary cracks, surface through cracks, and structural cracks to varying degrees.
Cracks in the exterior wall not only greatly reduce the protective effect on the exterior wall of the building, but also have a certain impact on the aesthetics of the painted surface. In order to make up for the above defects, before painting the exterior wall latex paint, a layer of exterior wall putty must be scraped on the wall; the quality of the exterior wall putty is the key.
The DKL automatic dynamic crack resistance Tester designed and manufactured according to JG/T157-2004 is used to test cement, polymer powder, synthetic resin emulsion or other materials as the main binder, together with fillers, additives, etc. External wall leveling putty.
2. Working principle:
After the motor is decelerated by the gear, it drags the ejector rod to move up, and the cutting edge generates an upward force, so that the asbestos cement board gradually produces fine cracks in the specified area and controls the slow expansion of the cracks. Observe the cracking of the putty layer to represent the resistance of the putty. The ability of the base material to propagate cracks.
3. Main technical indicators:
1. Cutting edge length: 150mm
2. Cutting edge angle: 30°
3. Maximum sum:20mm
4. Ascent rate:3mm/min
5. Frame specification:2001502 (mm)
4. How to use:
1. Put the frame on the 200×150 (mm) asbestos cement board. Then apply the prepared putty to the frame.
2. Remove the frame, and put the scraped asbestos cement board in the standard environment for curing for 7 days. For each sample, three test panels shall be prepared at the same time.
3. Fix the cured test plate on the working table of the instrument, turn on the power switch and then start the rising switch, and the cutting edge will rise slowly.
4. The cutting edge continues to rise slowly. At this time, pay attention to observe the blank area of the asbestos board. When cracks are found, use a vertical reading microscope to observe and record the crack width at any time until the putty layer cracks. After the stop switch is activated, the cutting edge no longer rises.
5. Record the maximum width of cracks in the asbestos cement board before the putty layer cracks. Accurate to 0.02mm.
6. Start the down switch to return the cutting edge to its original position.
7. Loosen the fastening nut and pressure plate of the test plate, and remove the test plate. Then put another test plate and repeat the above test steps.
5. Judgment of the result:
Among the three test panels, the arithmetic mean of the test results of each test panel with the closer numerical value is taken as the final result.
6. Precautions for use:
1. When the putty is applied and scratched, the surface should be smooth and free of air bubbles.
2. Pay attention to the edge of the putty layer when removing the frame, and there should be no cracking or damage.
3. When reading with a reading microscope, the cutting edge should not abdicate to prevent asbestos cement board
