earticle

영어

The purpose of this study is to investigate the effect of different levels of cement replacement(0, 5, 10, 15, 20, 25%) by copper
slag on the expansion of mortar bars containing reactive aggregates. The experimental program included expansion measurement of
the mortar bar specimens, also the determination of the morphology and composition of the alkali-silica reaction products by using
scanning electron microscopy(SEM), energy dispersive x-ray(EDX), and x-ray fluorescence spectrometer(XRF).
The results of the experimentation are as follow.
1) From the result, the expansion levels of mortar-bars containing CoS reduced as replacement levels increased. and the 25%
replacement of CoS produced the least expansion.
2) The amount of A.E.W decreased with an increasing amount of CoS replacement, which indicated that the amount of
alkali-silica reaction products decreased an increasing amount of CoS replacement.
3) After the accelerated test, SEM and BEM analysis showed the presence of alkali-silica gel and rim around the aggregate and cement paste, however the reaction products decreased markedly as the level of replacement was increased.
4) The presence of CoS changed significantly the alkali-silica gel composition, highlighting the strong relationship between the gel composition and expansion rate. Containing CoS, the higher replacement level, the higher CaO/SiO2, CaO/(Na2O)e, and EBIV ratio in the alkali-silica gel, the lower the gel's capacity for expansion.