01044654

Component

The paper presents the results of multi-objective laboratory study dedicated to evaluation of scaling resistance of ternary concrete prepared using varying quantities of class C fly ash and silica fume. Several experimental variables were included in the research and statistical analysis was performed to examine specific effects of each of the variables on the amount of scaling. The first variable studied was the relative amount of fly ash (FA) and silica fume (SF) used in the ternary cementitious system to determine its optimum value with respect to scaling resistance. The amount of fly ash used was either 20% or 30% by mass of total cementitious materials. The content of silica fume was either 5% or 7% by mass of total cementitious materials. The second variable evaluated was the type of the initial curing regime and its impact on the extent of scaling. The curing regimes compared included air drying, 3 days under wet burlap, curing compound applied for 7 days, and 7 days under wet burlap. The last variable assessed was the time of exposure to F-T cycles in the presence of deicing salt which included testing at either early age (14, 17 or 21 days depending on the initial curing regime) and the late age (90 days). The major finding from the conducted research was that the ternary mixtures containing 20% FA are much less prone to scaling than the mixtures with 30% FA. The mixtures with 20% FA were also found to be less sensitive to the initial curing conditions. The late exposure to freezing-thawing cycles in the presence of deicing salt did not significantly improve the scaling resistance of all the evaluated mixtures, most probably due to differences in scaling mode associated with the exposure times evaluated.

01042056

07-3393

English

16p

2007

Transportation Research Board 86th Annual Meeting

CD-ROM

Figures (5) ; References (24) ; Tables (4)

Admixtures; Cement; Curing agents; Curing and setting agents; Fly ash; Mixtures; Scaling (Concrete); Silica fume

Class C fly ash; Early age (Concrete); Ternary blend concrete; Ternary cements

Highways; Materials; I32: Concrete

Transportation Research Board Annual Meeting 2007 Paper #07-3393

TRIS, TRB

Feb 8 2007 8:05PM