Presented are the results of a laboratory-scaled test program conducted to evaluate the effectiveness of (a) pressure injection, and (b) polymer impregnation repair techniques for use in in situ repair of cracked concrete hydraulic structures. In general, the test results indicate that pressure injection can be used to effectively restore the integrity of air-dried and water-saturated cracked concrete. Polymer impregnation can be used to improve the quality of the concrete surrounding the crack network. However, its effectiveness in sealing the crack network is dependent upon the viscosity of the impregnant being used. The two methods can be used in conjunction to effectively repair and improve the overall quality of the structure to be rehabilitated.

Presented are the results of a program conducted to identify the repair methods and materials currently being used to repair and rehabilitate concrete structures deteriorating as a result of cracking and spalling. These repair methods and materials were evaluated for their applicability to the in situ repair of concrete hydraulic structures. From this evaluation, the following three repair techniques were identified as best suited for in situ repair procedures: pressure injection, polymer impregnation, and addition of reinforcement. Case histories illustrating the application of each technique are presented. Recommendations are made for work to be performed to make these systems more applicable to the repair of hydraulic structures. Keywords: Concrete, Cracking, Hydraulic structures, In situ repair, Polymer impregnation, Post reinforcement, Pressure injection, Spalling.

Presented are the results of the fourth and final phase of a research program directed toward identifying in situ repair procedures to be utilized in the rehabilitation of cracked concrete hydraulic structures. Emphasis of the laboratory and field research performed in Phase Four was directed toward the optimization of equipment and materials to be used with pressure injection repair techniques. Once optimized, the repair procedure was demonstrated in a field test performed at Lock and Dam 13 on the Mississippi River, Fulton, IL. (ttl).