SIMPLIFIED NON-DESTRUCTIVE METHOD FOR DETERMINING THE INTEGRITY OF HOLLOW-CORE SLABS

Abstract

The article presents the results of analysis of reinforced concrete hollow-core prestressed bench non-formwork molding floor slabs, manufactured using extrusion technology for defects formed as a result of a combination of a number of climatic effects during the construction of the building. The appearance of this kind of defects is quite common in construction practice. The issues of eliminating the causes of such defects, as well as strengthening damaged ceilings, are not the subject of this study. The purpose of the analysis was to identify damage to concrete and damage to the integrity of the slab ribs, which are not always available during visual screening. Existing methods of non-destructive testing with the help of specialized equipment make it possible to determine the strength of concrete as well as the presence of cracks and their configuration in products. The disadvantages of such methods include: high cost of equipment, the necessary level of qualification of specialists using it and the impossibility of its use for mass verification of the integrity of slabs. Therefore, it became necessary to develop a method for detecting defects in prefabricated structures for prompt inspection at the construction site. The proposed method makes it possible to quickly check the presence of significant defects in the construction due to sound audible analysis from strikes by a hammer on the slab. The simplified method of determining the integrity of hollow-core slabs makes it possible to narrow the volume of thorough and time-consuming instrumental studies during a complete inspection of the object, allocating places that need a thorough examination of damaged areas of structures from the total volume of prefabricated slabs of the object. According to the results of the research, it was determined that sound can be divided into three main types that characterize the nature of the structure defect: voiced sound indicates that the structure is not damaged, thud sound - the structure is damaged by near cracks, intermediate sound - the structure has deep cracks, mainly in a vertical rib.