Title: Classification and Quality System for Concrete Repair Mortars

Author(s): S. T. Chan, P. R. Ainsworth, and A. S. Read

Publication: Symposium Paper

Volume: 128

Issue:

Appears on pages(s): 609-624

Keywords: concretes; inspection; mortars (material); patching; repairs; quality control; site preparation; tests; Manufacturing

DOI: 10.14359/3511

Date: 11/1/1991

Abstract:
The Hong Kong Housing Authority's annual maintenance budget currently runs at around US$140m, approximately US$13m of which is expended on patch repairs to spalled and delaminated concrete, totalling 65,000 mý per annum. In recent years, a large number of different proprietary brands of repair material, both prebagged and site-mixed, have been used and new materials are continually being introduced. Two basic problems have been encountered: determining the suitability of materials for various applications, and controlling the preparation and application of repair mortars. Manufacturers of proprietary materials tend to use different tests and standards against which to evaluate the performance of their products and, with regard to the assessment of the performance and quality of repairs as applied, there are presently very few internationally accepted testing standards. The Housing Department has, therefore, developed its own series of tests and administrative procedures for classifying concrete repair mortars and controlling the quality of repairs. These include prequalification tests and routine quality control tests required to be undertaken by materials suppliers, the establishment of an approved list of materials, field trials undertaken at the commencement of repair contracts, and quality control tests undertaken during the contracts. This paper describes the background to and development of these procedures. Avenues for further development are also discussed.