Empty drum crack: During winter construction, low temperatures can cause the mortar to freeze. When it thaws in spring, this can lead to poor adhesion between the surface layer and the base layer, resulting in hollowing or even chalking in severe cases. To avoid this, outdoor work should be carried out when the temperature remains above freezing, making winter construction unsuitable. 6.1.2 When backfilling the ground or step base, it should be done in layers and compacted gradually. Otherwise, it may lead to hollow cushion areas and cracks in the concrete cushion and base layer. The thickness of the step concrete cushion should not be less than 8 cm. A steel mesh should also be installed beneath the base material. Settlement joints or expansion bars should be included for foundations and steps with different structures to prevent uneven settlement and cracking. If the base layer has significant surface deviations, improper treatment or construction can result in hollow cracks. For example, if each plaster layer is applied too tightly without proper watering and curing, the bond strength between the layers will be weak, increasing the risk of separation between the surface and the base. Insufficient cleaning and improper treatment of the base layer are often the main causes of cracks between the surface and the base. Therefore, strict adherence to process standards is essential, with special attention given to base preparation and maintenance. Uneven patterns typically occur due to improper timing of the layout, inconsistent force application during work, or inadequate finishing. It is important to provide better technical training, guidance, and sample boards to ensure proper execution during construction. Pits on the surface can appear when large areas are not properly tested before installation, especially if the surface layer lacks sufficient strength. This highlights the importance of thorough pre-construction inspections and quality control measures. Performance advantages: VTM Tube,Tube VTM,VTM Tube Price,VTM Test,VTM Test Tube,Lab Test Tube,Small Test Tube,VTM Sampling Tube Yong Yue Medical Technology(Kunshan) Co.,Ltd , https://www.yonyue.com
1.Strong water absorption capacity
2.Increase the collection and release of samples
3.Good abrasion resistance
4.Do not scratch the wiped device
5.No chip drop
6.100% sterilization and disinfection
Operating Steps:
1 Touch the swab to the surface where it is aimed to obtain the sample.
2 Remove the tube cap and put the swab into the transport medium.
3 Break the shaft of the swab so that it will fit in the tube.
4 Close the cap securely.Write on the tube the necessary information about the patient and sample.