Laboratory tests and analysis of CIPP epoxy-resin internal liners used in pipelines – part I: comparison of tests and engineering calculations

Abstract Tests that were carried out in order to obtain knowledge of the actual values of strength parameters obtained by CIPP liners that are used to repair pipelines. Specimens of liners made of high quality polyester felt cured with epoxy resin were subjected to tests. The scope of the performed studies corresponded with the scope of acceptance tests, which are carried out in the investment process during quality control of renovation works. Specimens of liners taken from sewers with 3 different diameters, i.e. 200mm, 350mm and 500mm were selected as representative for underground sewage networks. The obtained results enabled the calculations carried out in the course of design work to be verified, and differences between the model values of the strength parameters obtained from the calculations, and real values that are burdened with irregularities resulting from the conditions prevailing at a construction site and which were obtained for specimens taken from their built-in locations to be compared. The tests confirmed that it is possible to renovate - using CIPP liners - sewers with a lot of structural and material damage that negatively affects a liner‘s geometry. The implementation of the reinforcing internal coating in a sewer enables its further safe operation. The direct application value of the research involves the enlargement and clarification of knowledge concerning the actual load-bearing capacity of CIPP liners.