磷掺杂对阿利特介稳结构及水化性能的影响

Influence of Phosphorus Doping on Metastable Structure and Properties of Alite

采用X射线衍射结合Rietveld方法、红外光谱、差示扫描量热、扫描电镜及微量热分析等,研究了磷掺杂对阿利特晶体结构、多晶转变、微观形貌及水化性能等的影响。结果表明:在典型组成的阿利特中,掺1%P_2O_5(质量分数,下同)可稳定R型阿利特,但其在650~850℃介稳,向低温晶型转变。低掺量P_2O_5(≤0.2%)基本不影响阿利特水化性能。当P_2O_5掺量在准同型相界附近(0.5%)时,阿利特早期水化活性最高。随P_2O_5掺量增加,阿利特晶粒尺寸增大,早期活性降低,主水化反应减缓,但中后期活性增加。掺磷稳定R型阿利特可显著提高阿利特强度。

The influence of phosphorus doping on the crystal structure, phase transformation, microstructure and hydration properties of alite was investigated by X-ray powder diffraction with the Rietveld method, differential scanning calorimetry and Fourier transform infrared spectroscopy, scanning electron microscopy and isothermal calorimetry, respectively. The results show that the P205 addition of 1% （in mass fraction, the same below） can stabilize R-type alite. However, it is unstable at 650-850 ℃, which transforms into lower temperature forms. P2O5 at a lower content （i.e., ≤0.2%） does not affect the hydration characteristics and strength properties of alite. When the content of P205 is close to the morphotropic phase boundary, alite shows the highest early hydration reactivity. The length-diameter ratio of alite and the early hydration reactivity decrease, the main hydration slows down, but the rate of hydration increases during the deceleration period when the amount of P2O5 increases. The stabilization of R-type alite can greatly improve the compressive strength of alite.