City University of New York. City College. Dept. of Civil Engineering

New York (State). Dept. of Transportation

C-02-03

Tech Report

New York

New York (State). Dept. of Transportation

The two-fold focus of this study was (a) to develop an understanding of the mechanisms responsible for causing cracking in the concrete; and (b) to study the influence of the local materials on the performance of NYSDOT’s HP concrete mixture. Recommendations for minimizing the premature cracking in HP concrete decks related to restrained volumetric contraction are developed from the results of this investigation. It is important to reduce the total temperature rise and the temperature gradient across the steel girder to minimize the level of tensile stress in concrete in the first few days after casting, while the concrete goes through the heating and cooling produced by hydration heat. The local materials for use in HP concrete should be carefully evaluated. The type of coarse aggregate used in the mixture produces significant differences in the strength and elastic modulus of concrete. Differences in cementitious material contribute to significant differences in autogenous and drying shrinkage. Recommendations pertaining to cementitious materials are: (a) If silica fume is used, it should only to be added separately to the mix, unless the reactivity of blended silica fume is established and found comparable to silica fume addition; (b)Only the use of Type I/II or Type II cement should be permitted; and (c) When ground granulated blast furnace slag is used, it should be evaluated to ensure that it does not provide high early reactivity.

PDF

SPR Project C-02-03

US Transportation Collection