苯丙共聚物改性硫铝酸钙胶结料-无水石膏复合体系的水化

Hydration of Styrene-Acrylic Copolymer Modified Calcium Sulphoaluminate Clinker with Anhydrite

采用量热仪、X射线衍射仪、热重、扫描电镜、电感耦合等离子光谱等方法研究了苯丙共聚物(SA)对硫铝酸钙胶结料-无水石膏复合体系早期水化的影响。结果表明:SA会延缓水化进程,减少水化加速期钙矾石(AFt)、单硫型水化硫铝酸钙(AFm)和Al(OH)_(3)(AH_(3))含量,促进AH_(3)与石膏和氢氧化钙反应生成AFt,并促进水化后期AFt向AFm转变。同时,SA会迅速降低体系孔溶液的表面张力,随着水化反应进行表面张力趋于稳定;SA也提高了孔溶液的pH值,增大OH–浓度,影响了体系中Ca^(2+)、SO_(4)^(2–)和[Al(OH)_(4)]^(–)的浓度和比例,减小水化初期水化产物的离子浓度积,降低水化产物析出速率,进而延缓水化进程、减少水化产物。

The effect of styrene acrylic(SA)copolymer on the early hydration of calcium sulphoaluminate-anhydrite composite was investigated by calorimetry,X-ray diffraction,thermogravimetic analysis,scanning electron microscopy,and inductively coupled plasma-optical emission spectroscopy.The results show that SA can delay the hydration process,reduce the content of ettringite(AFt),single sulfur calcium sulphoaluminate hydrate(AFm)and Al(OH)_(3)(AH_(3))in the accelerated hydration period,and promote the reaction of AH_(3) with anhydrite and calcium hydroxide to form AFt as well as the transformation of AFt to AFm in the late hydration period.Also,SA can rapidly reduce the surface tension of the pore solution,and the surface tension tends to be stable within the hydration reaction.SA can increase the pH value of the pore solution,increase the concentration of OH–and affect the concentration of Ca^(2+),SO_(4)^(2–) and[Al(OH)_(4)]–in the composite,and decrease the ion concentration and the precipitation rate of hydration products at the initial stage of hydration,thus delaying the hydration process and reducing the hydration products.