Real-time monitoring the electrical properties of pastes to map the hydration induced microstructure change in cement-based materials

Using water vapour and N2 isotherms to unveil effects of SCMs on nanopores and evaluate hydration degree

“…The difference between binary and CEM I hcp becomes larger at higher w/b. This reveals a more evident refinement effect from SL and FA, resulting in a larger reducing effect on the moisture and chloride transport [7,35,36,43]. The volume of open LGP pores (3.3-12.3 nm) is increased by the blending of SL and FA, and this effect is significant on hcp with a w/b of 0.35.…”

“…Two different kinds of SCMs (ground granulated blast furnace slag and fly ash) and limestone were used to replace part of Portland cement to produce the blended pastes. Detailed information on the slag (SL), fly ash (FA) and limestone (LL) powder is described in [35]. Table 1 presents the mass proportions of the 11 samples.…”

“…The ion concentration in the pore solution was calculated with the chemical composition and water content, which has been previously illustrated in [35]. Herein, we subtracted the alkali ions in the C-S-H by taking the adsorption coefficient of 1.2 % for Na and 2 % for K [64], respectively.…”

“…The presence of Fe and Al in the binder system will form the Fe-siliceous hydrogarnet (Si-hydrogarnet) [82]. The limited amount of limestone in cement (see the composition of CEM I in [35]) will induce the formation of hemicarboaluminate (Hc) and monocarboaluminate (Mc) [79,83]. The blending of limestone will stabilise the Mc, so there is no Hc in the ternary SL system at a later age [84] (also see Fig.…”

Long-term performance of reinforced concrete under a de-icing road environment

“…Yio et al [28] reported that the slag blended pastes with w/b of 0.3 had a higher gas transport coefficient than the plain paste. A recent study also found that slag had a much weaker effect on chloride migration coefficient of pastes with w/b of 0.35 than those with w/b of 0.45 at 6 months [29]. Therefore, when the concretes are mixed with w/b of 0.4-0.5, the reducing effect from slag is much clearer especially in the depth larger than 20 mm.…”