Title: Injectable Cementitious Materials for Cracks in Hydraulic Structures

Author(s): J. Mirza

Publication: Symposium Paper

Volume: 128

Issue:

Appears on pages(s): 217-232

Keywords: cracking (fracturing); high early strength cements; repairs; hydraulic structures; particle size distribution; portland cements; viscosity; Materials Research

DOI: 10.14359/1891

Date: 11/1/1991

Abstract:
Concrete structures, old or new, often experience formation of cracks, even though these are accounted for by the designer at the time of construction. To repair these cracks, a large number of injectable inorganic materials (cements and cementitious grouts), organic materials (epoxies, polyurethanes, polyester, etc.) and mixtures of both have been used successfully and unsuccessfully. Cementitious materials seem to arouse great controversy among engineers, especially with regard to the acceptance levels of the consistency (water-cement ratio) to be used for injection. A hydraulic facility in Quebec is therefore evaluating a number of cementitious materials as well as various epoxies and polyurethanes for repairing its concrete structures. The paper describes the results of a study performed in the laboratory using normal portland cement (Type 10) and high early-strength cement (Type 30) both with and without superplasticizers, and two ultrafine cements, and recommends an arbitrary lower and higher limit of the water-cement ratio, which could be suitable for crack injection. It also presents some physical and mechanical data on these cements. 110-691