In order to obtain quickly the influences of blast furnace slag and water-binder ratio on the leaching behavior of cement-based material and its corrosion resistance in water environments, an accelerated calcium leaching experiment on a slice specimen with slag-cement pastes in 6M NH 4 Cl solution was carried out. Using the saturation-drying weighing method, X-ray diffraction (XRD) and the scanning electron microscope (SEM/EDS) measurement, the influences of water-binder ratio and slag content on the porosity, phase composition, microstructure morphology and Calcium-Silicon ratio of slag-cement pastes in the process of calcium leaching were analyzed. Results show that, compared to cement pastes without slag, the slag-cement paste with the appropriate slag content has a low rate of microstructure deterioration and a good leaching resistance. The optimum slag contents in slag-cement pastes are respectively 40% and 50% corresponding to the low and high water-binder ratio. The porosity, Calcium-Silicon ratio and microstructure morphology of slag-cement pastes exhibit small change in the process of accelerating leaching, and this indicates that the slag-cement pastes with the optimum slag content can provide the best performance of calcium leaching resistance in the soft-water environment.

In order to investigate the influence of slag on the leaching behavior of cement mortar lined in ductile iron pipe in a flowing solution, two types of ductile iron pipe specimens lined with ordinary-and 40% slag-cement mortar are firstly prepared, then, an accelerated leaching experiment on the prepared specimens is carried out by using a 6M ammonium chloride solution at a flow rate of 0.3m/s. The parameters of linings at different leaching times, such as porosity, pore size distribution, phase composition and Calcium-Silicon (Ca/Si) ratio, were analyzed by using the saturation-drying weighing method, mercury intrusion porosimetry (MIP), X-ray diffraction (XRD) and scanning electron microscopy in back scattered electron mode (ESEM-BSE) measurements. Results show that, the mixture of 40% slag in cement-mortar lining can reduce its initial porosity and Calcium-Silicon ratio, and improve its pore size distribution and phase composition. In the accelerated leaching process, the porosity, phase composition and Calcium-Silicon ratio of the slag-cement-mortar lining with 40% slag have smaller change than that of the ordinary-cement-mortar lining without slag, and it indicates that the addition of slag can effectively improve the calcium leaching resistance of cement-mortar lining in ductile iron pipes in water supply engineering.

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How to ev aluate the fuel gas operation (FGO) of various working groups (WGs) and working shifts (WSs) in reheati ng furnace is still ambiguous problem. In this paper, a nov elty times eries FGO evaluation model was propos ed. The strategy mainly included: Fi rstly, the fuel gas per ton steel (FGTS) was calculated i n certain time interval; Secondly, the FGT S times eries data set was formulated in s tatistical period; Thirdly, the FGTS time-series data set was divided according to worki ng schedule; Lastly, the FGO evaluation model was established. Case study showed that: i) The fuel gas operation evaluation results of various WGs in different WSs were accorded wi th normal distribution; ii) For various WGs, A WG performed best, followed by C WG and D WG. The performance of B WG was the worst due to its violent fluc tuation of fuel gas operation evaluation res ults in three WSs ; iii) For different WSs, the day WS and swi ng WS performed well, whereas the performanc e of night WS was unsatisfactory. Discussion results showed that the improv ement of working skills, working responsibility and working passion, which were effec tive measure to ac hieve energy saving in terms of operation, should be enhanced through skills traini ng and the reward and punishment system. Generally, this novelty time-series FGO evaluation method could also be applied to other industrial equipment.