Title:
Shorter Autoclave Cycles For Concrete Masonry Units
Author(s):
Thomas B. Redmond, Jr.
Publication:
Symposium Paper
Volume:
32
Issue:
Appears on pages(s):
57-98
Keywords:
autoclaving; compressive strength; concrete block; concretes;
curing; drying shrinkage; expanded shale aggregates; expanded slag aggre-gates; heating; high temperature;
DOI:
10.14359/6600
Date:
7/1/1972
Abstract:
The report data are from three investigations on autoclave curing of block-type concrete mixes. Variables were presteaming time, heating time, heating rate, and time at maximum temperature and pressure of laboratory and plant-manufactured specimens of three aggregate types. The principal finding was the high strength and low drying shrinkage generally obtained with two hours of curing at 365 F. A one-hour cure at 400 F produced optimum strength in the test series investigating higher temperatures. With the industry trend to faster rail charging systems, data indi-cate the feasibility of four curing cycles per autoclave per day. However, author recommends that time at maximum temperature should not be shorter than five hours unless long-term individual plant tests have consistently demonstrated good results.