Title:
Freezing and Thawing Durability of Roller-Compacted Concrete
Author(s):
T. P. Dolen
Publication:
Symposium Paper
Volume:
126
Issue:
Appears on pages(s):
101-114
Keywords:
air-entraining agents; concretes; durability; petrography; freeze thaw durability; roller compacted concrete; Materials Research
DOI:
10.14359/2049
Date:
8/1/1991
Abstract:
Roller-compacted concrete (RCC) is a non-air-entrained concrete of no-slump consistency, which is placed by spreading in horizontal layers and consolidated by smooth-drum, vibrating rollers. Though used in other applications for many years, RCC in its present form has been used to construct concrete gravity dams by taking advantage of the high production rates and attendant cost savings associated with the use of earthwork equipment to transport, place, and "compact" the material. RCC is finding increasing use in thick paving applications, taking advantage of the high production rates of asphalt paving equipment. The earlier attempts to entrain air in lean, dry RCC mixtures were nsuccessful, and the freeze-thaw (FT) durability of RCC was considered poor. Dam structures were designed so that the RCC was protected from weathering by zones of conventional air-entrained concrete, or "sacrificial" RCC was placed beyond the design cross section. This raised the cost of these structures due to the higher unit cost of the conventional concrete or the added costs associate with the larger cross section. With the expanding use of RCC, particularly in paving applications, it is desirable to attempt to develop air entrainment to satisfy FT durability criteria and allow RCC to fully complete with conventional concrete and asphalt in the marketplace. The Bureau of Reclamation, Denver, Colorado, has been investigating the FT durability of RCC through laboratory testing, outdoor exposure testing and recent field demonstrations. The goal of the program is to reduce the need for conventional concrete facing and expand the applications of RCC where FT durability is a requirement, such as in the facing of embankment dams. This paper summarizes the results of testing performed to date in the laboratory and in the field.