Binary Binder Research Articles

Effect of Mixture Composition on Relative Strength of Highly Flowable Underwater Concrete

Concrete used for underwater repair is often proportioned to spread readily into place and self-consolidate, and to develop high resistance to segregation and water dilution. A study was conducted to determine the effect of the dosage of antiwashout admixture, water-cementitious materials ratio (w/cm), and binder composition on the relative residual strength of highly flowable underwater concrete. Two types of antiwashout admixtures and 4 binder compositions were used. Results indicate that for a given washout mass loss and slump flow consistency, greater relative residual strength can be secured when the dosage of antiwashout admixture is increased, the w/cm reduced, and a binary binder with 10% silica fume substitution or the ternary binder are employed.

Behavior of Carbon Obtained from Pitch and Resin Added to Carbon-Containing Refractories

Pitch and resin are used as binders of carbon-containing refractories, because of their high degrees of carbonization. Carbons formed by decomposition of these binders during heating have different high temperature properties. In this paper, crystallization, oxidation, true density and microstructure of carbons obtained from pitch, resin and their mixtures were examined. As compared with carbon obtained from resin, carbon obtained from pitch was higher in degree of crystallization, true density and starting temperature of oxidation. In other words, similar oxidation properties of carbon from resin were obtained when resin was heated at temperatures above 500-600°C higher than that for pitch. Carbon obtained from mixtures of pitch and resin, especially, for 80wt% pitch and 20wt% resin, had the highest starting temperature of oxidation. The mixtures of pitch and resin thus binary binder seems to be better than pitch or resin as binders for carbon-containing refractories.