Abstract
In this thesis, a generic specification and test methodology for developing and evaluating novel distribution main repair systems for circumferential cracks in iron pipes has been proposed. The performance criteria suggested in the specification are (i) watertight seal, (ii) strength, (iii) crack bridging ability, (iv) minimum interruption to supply, (v) water quality approval, (vi) durability, (vii) minimum financial cost, (viii) versatility, (ix) flexibility, and (x) reduction in environmental impact. A case study of novel polymeric repair systems was investigated using the generic methodology as the basis for performance evaluation and testing. Polymeric paste and bandage-type repair systems, proposed by the author, form a watertight seal over a failure by chemical bonding to the iron substrate, rather than through mechanical compression of an elastomeric gasket, as is the case with current repair clamps. The materials tested were typically intended for use within the water industry for other applications than repair and included epoxy, silicone, acrylic and phenolic resins, butyl rubber, and various bandage-type products. In addition, the effect of surface preparation on the polymer/iron bond strength was investigated. It was concluded that no currently available products were suitable as water pipe repair systems when used in the manner described in this thesis. Epoxy resin applied as a paste repair was found to be the strongest of the systems tested. The low viscosity of the liquid polymer products reduced the ease with which paste-type repair systems could be applied to a pipe. For most of the products tested there was a requirement for mains depressurisation whilst curing, resulting in an interruption to the supply of water to customers.