Repairing concrete dams with cement-based grouts: Case histories

Abstract

This document aims at compiling a considerable number of successful rehabilitation examples involving the use of cement based grouts in the repair of cracks in concrete dams and its content is based on information that was previously published. This article starts with a brief introduction regarding the use of cement based grouts in the injection of cracks in concrete dams, in which advantages and drawbacks of the use of cement based materials within this scope are discussed. In the same context, particularities of the main four structural types of concrete dams, i.e. gravity, buttress, arch and multiple arch-buttress, are also addressed. Each one of the following four chapters are focusing on the above mentioned types of concrete dams. The chapter three presents two examples of concrete gravity dams that were successfully rehabilitated. Considerable seepages were detected in both gravity dams presented. In Isle-Maligne dam, leakages in horizontal construction joints occurred due to leaching and freeze-thaw cycles, whereas deterioration of Kuromata dam was mostly caused by ageing. In chapter four, three buttress dams are given as examples: Big Eddy, Pracana and Storfinnforsen dam. The Big Eddy dam showed leaching of horizontal construction joints caused by open lift joints. Pracana, on the other hand, had degraded faces and cracks provoked by swelling reactions. Storfinnforsen exhibited cracking and spalling as well as leakage. Chapters five and six are solely focused on one case history each: the Bimont arch dam and the Daniel-Johnson arch-buttress dam respectively. Bimont was subjected to swelling reactions, which resulted in cracking. Daniel-Johnson dam also cracked considerably, although due to different causes: the geometry of the structure and thermal stress. All the cases were resolved with cement grouting combined with other repair materials and measures, such as epoxy resin, shotcrete, installation of geomembrane or grouting of contraction joints. These and other successful rehabilitation operations should serve as guidance in comparable upcoming rehabilitation operations, involving grouting of concrete dams with cement based materials.