Title: Development of Performance Criteria for Dimensionally Compatible Cement-Based Repair Materials
Author(s): J. E. McDonald, P. H. Emmons, A. M. Vaysburd, and D. W. Scott
Publication: Symposium Paper
Appears on pages(s): 441-458
Keywords: concrete; drying shrinkage; repair; test
The unacceptably high failure rate for concrete repairs is a major Synopsis: problem in the repair industry. To achieve durable repairs, it is necessary to consider the factors affecting the design and selection of repair systems as parts of a composite system. Compatibility between repair material and existing substrate is one of the most critical components in the repair system. This paper summarizes research initiated by the Corps of Engineers to develop performance criteria for cement-based repair materials. Results of laboratory and field performance tests were correlated to provide a basis for development of performance criteria for the selection and specification of dimensionally compatible cement-based repair materials. Proposed performance criteria include a minimum value for tensile strength and maximum values for modulus of elasticity, drying shrinkage, and coefficient of thermal expansion. Also, resistance to cracking in restrained shrinkage tests is a requirement. A data sheet protocol is proposed for cement-based repair materials that would provide reliable, standardized information on pertinent material characteristics. Also, current efforts to develop a comprehensive analytical model to predict cracking resistance of repair materials are briefly described.