羟丙基甲基纤维素对硫铝酸盐水泥水化的影响

Effect of Hydroxypropyl Methyl Cellulose on Hydration of Calcium Sulfoaluminate Cement

采用X射线衍射分析、热分析、等温量热法和电感耦合等离子光谱法研究了羟丙基甲基纤维素(HPMC)对硫铝酸盐水泥水化的影响,并从孔溶液的性质和组成方面分析了其对水泥水化的影响机理.结果表明:HPMC改变硫铝酸盐水泥的水化放热速率,增加钙矾石(AFt)、单硫型水化硫铝酸钙(AFm)和铝胶(AH_(3))的含量,促进AH_(3)与CaSO_(4)和Ca(OH)_(2)反应,并促进AFt向AFm转变;HPMC降低硫铝酸盐水泥孔溶液的表面张力,增大孔溶液的pH值,降低孔溶液中SO_(4)^(2-)的浓度,增加Ca^(2+)和[Al(OH)_(4)]^(-)的浓度,进而增大AFt和AFm的离子浓度积,有利于水化产物的析出,从而促进水泥水化.

The effect of hydroxypropyl methyl cellulose(HPMC)on the hydration of calcium sulfoaluminate cement was studied by X‑ray diffraction analysis,thermal analysis,isothermal calorimetry and inductively coupled plasma‑optical emission spectroscopy.The influence mechanism of HPMC was analyzed from the perspective of the properties and compositions of the pore solution.The results show that HPMC changes the hydration heat release rate,increases the content of ettringite(AFt),monosulfate calcium sulfoaluminate hydrate(AFm)and alumina gel(AH_(3)),promotes the interaction of AH_(3) with CaSO_(4) and Ca(OH)_(2),and promotes the conversion of AFt into AFm.HPMC reduces the surface tension and increases the pH value of the pore solution,reduces the concentration of SO_(4)^(2-),increases the concentration of Ca^(2+)and[Al(OH)_(4)]-,thereby increases the ion concentration products of AFt and AFm,and benefits the precipitation of hydration products,hence promotes the cement hydration.