An Investigation of the Delay Period and Related Factors in Steam Cured Concrete

摘要

Studies showed that principally because of differences in their chemical composition cements have unique setting rates and produce concretes of different strengths and, in all probability, of varying durability. This investigation was designed to evaluate, in terms of early (one-day) strength, the effect of variations of time and temperature in the particular phases that make up a steam curing cycle on concretes containing cements of different setting rates. The investigation was divided into two phases, the purpose of the first phase being to determine: (1) if the optimum delay period (for producing macimum early strength) for a given concrete could be correlated to its stiffening rate as measured by the Penetration Resistance Needle Test (Proctor Method), and (2) what influence the type of cement and the different factors of a steam curing procedure have on the length of delay period. The purpose of the second phase was to learn how marked the effect of the gypsum content (expressed in cement analysis as percent S03) was on the early strength of steam cured concrete containing type III cement and to determine approximately the optimum content in keeping with maximum strength and minimum expansion.