The detection of building concrete component defects is divided into appearance defect detection and internal defect detection. This article will introduce the contents and methods of two types of detection.
Defect detection of concrete members
First, appearance defect detection
During the on-site inspection, it is advisable to conduct a full inspection of the appearance defects of the components within the inspection range; when not all the inspection conditions are available, the areas where the components are not inspected should be indicated.
Related parameters of appearance defects of concrete components can be detected according to the following conditions:
1 The length of exposed ribs can be measured with a steel ruler or tape measure;
2 The hole can be directly measured with a steel ruler, and the hole depth can be measured with a vernier caliper;
3 The location and range of honeycomb and loose can be measured with steel ruler or tape measure;
4 The position and range of hemp surface, peeling and sanding can be measured with steel ruler or tape measure;
5 The maximum width of the surface crack can be measured with a special measuring instrument for cracks, and the length of the surface crack can be measured with a steel ruler or a tape measure.
The appearance defects of concrete components shall be classified and summarized according to the defect category. The summary results may be expressed in a list or diagram and should reflect the distribution characteristics of appearance defects within the scope of inspection.
Internal defect detection
It is advisable to carry out all inspections on suspected internal defects or areas. When not all inspection conditions are available, the following components or parts may be selected for inspection according to agreed sampling principles:
1 important components or parts;
2 Components or parts with severe appearance defects.
内部 The internal defects of concrete members should be tested on both sides by ultrasonic method. When there is only one side, the impact echo method and electromagnetic emission method can be used for inspection. Core identification or pick-out verification should be performed for difficult areas.
声 The measurement of acoustic parameters when ultrasonic methods are used to detect internal defects of concrete components shall meet the following requirements:
1 The defect testing site should be determined according to the testing requirements and site operating conditions;
2 The surface of the positioning concrete should be clean and flat. If necessary, it can be ground with a grinding wheel or smoothed with a high-strength fast-setting mortar; the smoothing mortar should be well bonded to the concrete to be tested;
3 Under the condition that the accuracy of the first wave amplitude measurement is met, a higher frequency transducer should be selected;
4 The transducer should be kept tightly bonded to the concrete test surface through a coupling agent, and there should be no mud or sand in the coupling layer;
5 When testing, the ultrasonic propagation path should be avoided to be parallel to the axis of the internal steel bar. When it is unavoidable, the minimum distance between the line and the steel bar should not be less than 1/6 of the ultrasonic distance measurement;
6 The parameters such as emission voltage and sampling frequency should be set according to the ranging size and the appearance quality of the concrete. When testing the same side, the parameters of the instrument should be kept unchanged.
7 should read and record the sound time, amplitude and main frequency value, access the waveform if necessary;
8 When there is suspicious data in the test, the cause should be found in time, and if necessary, retesting or encrypted test points should be performed.
Internal defect detection of concrete components should provide information about the choice of side position, location, description of appearance quality, and the nature and distribution of defects.