Wiss, Janney, Elstner Associates, Inc., was requested by the U.S. Army Corps of Engineers to perform a laboratory study to evaluate injection materials for the filling and repair of deep, narrow cracks in massive concrete structures. The emphasis of this study was on epoxies; however, high-molecular-weight methacrylates, ultrafine cements, and polyurethanes were also considered. A laboratory test program was developed to evaluate the properties that are considered to be important for injection materials. These properties included viscosity, surface tension, gel time, penetration, and bond strength to wet concrete. A literature survey and telephone interviews were performed prior to selecting the materials for testing, and a spreadsheet was constructed to aid in choosing the materials to be tested. This report also includes the literature survey and laboratory test data. The objective of this proposed research is to determine the most promising products (materials), equipment, and procedures available that could most effectively be used to cause the material to most deeply and uniformly penetrate and "heal" existing cracks in massive hydraulic structures. (MM).

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.

This report provides the status of information, including research needs, on the performance of materials containing polymers used to repair portland cement concrete. The following types of repair materials were covered: sealant type materials for repairing active cracks, and polymer adhesives, polymer mortars and concretes, and polymer-modified mortars and concretes for repairing spalls and dormant cracks and for placing overlays. This report is considered a first step in the process of developing performance tests and criteria and is intended to serve as a guide in selecting performance requirements, degradation factors, properties related to performance, and relevant existing test methods and their parameters. Keywords: Overlays, Repair materials, Sealants, Spalls, Test methods.

Concrete mixtures were evaluated to determine which were most suited for placement underwater in thin lifts. The concretes were proportioned to have good workability, good abrasion erosion resistance, and good resistance to washing out of the cement paste. High-range water reducers (HRWR) were used to increase the workability and permit the use of low water cement ratios (W/C) to increase the resistance to abrasion erosion. Low W/C, silica fume, and antiwashout admixtures (AWA) were used to increase the resistance to washout. A washout test was used to determine the relative amount of cement paste lost when the concrete is exposed to a large volume of water. The two-point workability test was used to evaluate the relative workability properties of each mixture. The slump and air content were also measured for most of the mixtures. The test method for abrasion erosion resistance of concrete (underwater method) was used to determine the abrasion erosion resistance of each mixture. The results of these tests were used to determine the combination of materials necessary to produce concrete with the desired properties. Significant correlations that exist between the two-point measurements and washout measurements were examined. The effects that W/C, HRWR's, AWA's, fly ash, and silica fume have upon washout resistance and abrasion-erosion resistance were examined.

The surfaces of many of the Corps' concrete structures are subject to deterioration due to freezing and thawing, weathering, chemical attack, erosion, and other destructive mechanisms. Surface treatment of the concrete with a material to retard action of the forces is one way to reduce the rate of or eliminate deterioration. In the past, various surface treatments have been applied to concrete; some were successful, while others failed. In most cases the failures were due to either selection of the wrong surface treatment material or improper application. There is a need to evaluate various surface treatments to determine which would offer the best protection and what would be the proper ways to apply them. The objective of this study was to obtain information on the types of current surface treatment materials available, chemical compositions, and properties, and the performance of these materials in service conditions. Keywords: Abrasion, Erosion, Coating, Hydraulic structures, Concrete deterioration, Sealers, Surface treatments, Stone consolidants, Vapor transmittance.