Loading Tests with Rehabilitated Pipes by Spiral Wound Lining Method Evaluating Influence of Poor Adhesion and Potential Propagation of Separation

Abstract

In composite designing of rehabilitated pipes by spiral wound lining methods, evaluation of the ultimate state of adhesion between an existing pipe and its reinforcement member is important. If deformation on a rehabilitated pipe causes overall separation between the existing pipe and its reinforcement member, even small area of poor adhesion may cause serious degradation of its strength and rigidity. Specimens of full-scale rehabilitated pipes with SPR Method are prepared with different conditions of adhesion; overall bonded, overall unbonded, and partially unbonded. Overall unbonded specimens showed smaller strength and rigidity compared to overall bonded ones. However, both of strength and rigidity of partially unbonded specimens showed little difference to fully bonded ones. It is concluded that propagation of separation, which originates from an area of poor adhesion and leads to an overall separation, does not occur until the ultimate state of rehabilitated pipes, as far as good adhesive strength is secured in bonded area.