The Study on Pore Structure and Hydration Reaction of Co-melted Slag Blended Tri-Calcium Silicate Paste

• Main Authors: Hsiu-Hsien Wu, 吳修賢
• Other Authors: Kae-Long Lin
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/00277521472305270709

碩士 === 國立宜蘭大學 === 環境工程學系碩士班 === 98 === In this study, the slag sample were obtained by first grinding municipal solid waste incinerator (MSWI) fly ash and sewage sludge ash; varying composite fractions were then utilized. As defined by Murakami, Basicity=CaO/SiO2. The pouring point was lowest when basicity was 1. Therefore, the experimental design of basicity (CaO/SiO2) was 1.0. The molten slag was water-quenched to produce a fine slag, which was then further pulverized in a ballmill until the particles could pass through a #200 mesh sieve. The resultant pulverized slag was desiccated prior to testing. The compressive strength of slag blended tricalcium silicate (SBTCS) pastes decreased as the water-to- binder (w/b) ratio increased. The gel pore (<0.01 μm) volume of SBTCS pastes increased at a w/b ratio of 0.50 and 0.55. By using total porosity and capillary porosity values in conjunction with compressive strength values, one can generate an accurate statistical equation that describes the relationship between both parameters. Notably, compressive strength decreased rapidly for SBTCS pastes, likely due to the increase in macroporosity as porosity increased. For 50oC and 60oC of curing temperature, the SBTCS pastes had a greater compressive strength for up to 28 days. This may have been due to the presence of calcium silicate hydrates, the hydration product, which occurred during pozzolanic reactions, and filled the capillary pores. Subsequently, compressive strength reduced continuously as curing time increased up to 90 days. By the DSC analysis, at 50oC and 60oC of curing temperature, increasing the hydrates nucleation rate increased of SBTCS pastes for up to 14 days. At the curing temperature of 50oC and 60oC, the results of scanning electron microscopy (SEM) observations, the hydration products of the SBTCS paste remained coarsening during the later stage. At the curing temperature of 30oC and 40oC, the hydration products of incorporating slag into blended tricalcium silicate pastes was an increase in the number of fine pores as curing duration increased. The compressive strength of SBTCS pastes increased markedly at later stage.