Waterproof maintenance plays an important role in building maintenance.Due to economic, environmental protection or the nature of the leakage parts of buildings, in many cases, it is not allowed to give up the original waterproof layer for large-scale repair. Users all hope to have a point-to-point repair method, that is, where the leakage is repaired, the minimum cost is used to get the maximum benefit.Detection of building leakage is an important aspect of waterproof maintenance. Nondestructive testing can not only improve the work efficiency, but also reduce the damage to the building, avoid the misleading of personal experience, and greatly increase the accuracy of determining the leakage source.
The causes of leakage in many buildings are very complex, and it is difficult to find the leakage points.For example, for the roof, at present, the commonly used waterproof design is mostly two-layer waterproof coiled material. Because the waterproof coiled material construction adopts strip adhesion or point sticking, once leakage occurs, there will be water leakage problem, and the leakage point is difficult to determine; for example, after the construction of some basement floor, cushion, backfill, ceramsite concrete will be set on the bottom plate for later construction, once seepage occursLeakage, also very difficult to find the source of leakage.
At present, there are several commonly used leakage source detection methods as follows: 1) Observation analysis method, mainly through the observation of leakage phenomenon, combined with construction data, design drawings and personal experience to determine the possible leakage.The advantages of this method are simple, convenient and less investment; the disadvantage is that the accuracy of leakage point determination is not high based on experience analysis. In order to achieve good maintenance effect, it is necessary to expand the insurance coefficient of maintenance scheme, which is easy to cause high maintenance cost. 2) Open the inspection method, carry out destructive inspection on the leakage parts, and look for the leakage source.This method has the advantages of direct search and high accuracy, while the disadvantage is that it needs to carry out destructive inspection on the part of the building and increase the maintenance cost.
Several nondestructive testing methods
Nondestructive testing (NDT) is a testing method introduced into the quality control of construction projects in recent years.Nondestructive testing is a method to check and test the structural properties and state of the internal and surface of the specimen by means of physical or chemical methods and with the help of modern technology and equipment.It is mainly based on the variety of physical characteristics of the material, without damaging the performance and shape of the object to be tested, it can realize 100% inspection, so as to judge the quality status of the inspected object.The introduction of non-destructive testing to the maintenance of building leakage can not only improve the work efficiency, but also reduce the damage to the building, avoid the misleading of personal experience, and greatly increase the accuracy of determining the leakage source.At present, the non-destructive testing methods for building leakage include water pipe pressing method, infrared thermal imaging method, leak detector detection method and roof humidity detector method.
Pipe pressing method Water pipe pressing method is the most simple and effective method to test whether there is water leakage in water supply pipe by Jack. The water supply pipe in toilet, kitchen and balcony is easy to leak.
infrared thermography The infrared thermal imaging method uses the infrared detector, optical imaging objective lens and optical mechanical scanning system to receive the infrared radiation energy distribution of the object to be inspected and reflect it to the photosensitive element of the infrared detector. According to the different infrared radiation energy, the infrared thermal image shows different color areas.After the leakage of buildings, the water temperature difference between the water containing part and the non leakage part will occur. According to the principle of infrared thermal image, the leakage part can be determined.
Leak detector detection method Most leak detectors are based on the principle of sound vibration method or sound listening method.When the pressure pipe leaks, the noise generated by the pressure liquid jetting out of the damaged port, including the noise generated by friction pipe wall, the sound of impacting the surrounding buried layer media (such as bricks and soil), and the sound of water whirling and bubbling caused by the impact of long time may empty the surrounding buried layer. When this series of comprehensive sound is transmitted to the road directly above the buried pipeline, the instrument is usedThe sensor or vibration pick-up is used to receive the sound signal of the leakage, and then the host is used to amplify and analyze, and finally determine the location of the leakage point.The closer the leakage signal strength is to the leakage point, the stronger the signal is; otherwise, the weaker the signal is. By comparing the signal strength between each point, the leakage point can be detected.This method can be used for reference in the detection of leakage caused by pipeline rupture.