Injection of discontinuities in concrete dams with cement-based grouts

ABSTRACT Injecting discontinuities is a recurrent procedure for the rehabilitation of concrete hydraulic structures, namely repairing cracked dam bodies and deteriorated lift and contraction joints. Within this scope, a relatively detailed description of the most important cement injection grouts features is presented, including the main advantages and drawbacks compared to alternatives. The cement-based grouts are among the most utilised materials in these contexts. Economic and environmental related aspects are among the main advantages of cement-based grouts, although some technical features of these grouting materials are also favourable. The equipment utilised for the preparation and for the application of cementitious grouts is also mentioned. This document also addresses aspects related to the assessment of concrete dams’ stability, the preparatory works, the common methodologies and the standard precautions to have into account when planning a rehabilitation operation involving cement grouting for filling cracks or repairing lift or contraction joints in these massive structures. A list of successful rehabilitation case histories is provided, including a short description of the anomalies and their causes, as well as a summary of the main repair measures adopted for each situation.