【摘 要】
：
Common cement hydration accelerators such as e.g.calcium or aluminium salts achieve higher early strengm at the sacrifice of final strength which is undesirable.In this study, the effectiveness of C-S
【机 构】
：
Technische Universit(a)t München, Chair of Construction Chemistry, 85747 Garching, Germany;Siam Ceme
【出 处】
：
The 14th International Congress on the Chemistry of Cement (
论文部分内容阅读
Common cement hydration accelerators such as e.g.calcium or aluminium salts achieve higher early strengm at the sacrifice of final strength which is undesirable.In this study, the effectiveness of C-S-H-polycarboxylate (PCE) nanocomposites as strength enhancing admixtures was studied.Different MPEG-PCE copolymers exhibiting side chain lengths from 8, 17, 25, 45 to 114 ethylene oxide (EO) units were used to prepare the nanocomposites by precipitating C-S-H from Na2SiO3 and Ca(NO3)2 in the PCE solution.It was found that the longer the side chain of the PCE, the smaller is the particle size of the precipitated C-S-H, and the higher is the strength enhancing effect.Thus, the MPEG PCE sample possessing a side chain made of 114 EO units produces C-S-H particles of~ 30 nm, as was measured via dynamic light scattering, and increases early strength (16 hrs) up to 80 %.Opposite to this, the C-S-H particle size obtained from a PCE possessing only 8 EO units in the side chain was ~ 600 nm, and it showed only minimal effect on early strength.
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