Title: Curing of Concrete
Author(s): A. G. Timms, D. L. Robinson, H. J. Gilkey, Roy W. Carlson, W. R. Johnson, G. E. Burnett, and H. C. Vollmer
Publication: Journal Proceedings
Appears on pages(s): 701-724
Keywords: no keywords
Techniques for curing concrete must consider all the conditions, both natural and artificial, that affect the extent and rate of cement hydration. Well-cured concrete does not just happen; it is the result of careful control of the moisture content and temperature of the concrete. A survey of pavement curing methods in the 48 states indicates fairly uniform practice in initial curing methods but wide variations in final curing methods and total time of application. The initial curing method most widely permitted is covering with saturated burlap. For final curing, saturated cotton, felt or jute mats, membrane compounds, waterproof paper, saturated earth or ponding and covering with hay or straw are permitted. Length of curing period varies from 72 hours to 7 or more days. A summary of the factors which relate especially to the curing of concrete in building construction emphasizes where and how these differ from some of the problems encountered in other fields. Current practices, especially with regard to form removal and to temperature and moisture control in cold weather are discussed. Problems in curing mass concrete are similar to those for smaller sections with the addition of consideration of heat of hydration. Methods used must control the temperature differential between the face and interior of the massive sections. Some remedial measures are creating low temperature in the concrete when placing, limiting the height and rapidity with which the lifts are placed, use of embedded cooling systems or using steel forms which help dissipate the heat. A summary of the recommended curing practices for mass concrete based on the most recent report of Committee 612 is included. A discussion of membrane curing methods for concrete canal linings points out that white pigmented compound is preferred. Good material, proper time of application, adequate film thickness, and uniform coverage are important. Standard laboratory and field curing methods are summarized. The influence of economy in the standardization and establishment of acceptable curing specifications is discussed. Use of calcium chloride as a surface treat-ment or integrally for curing purposes, is explained.