改性磷石膏对石膏矿渣水泥水化过程的影响研究

采用质量分数为5％～25％的改性磷石膏、15％的硅酸盐水泥熟料、60％～80％的矿渣混合磨细制成石膏矿渣水泥,研究了改性磷石膏掺量对石膏矿渣水泥浆体的抗压强度、水化热、孔溶液pH值及水化产物的影响情况.结果表明,掺入改性磷石膏使得石膏矿渣水泥的3 d、7 d抗压强度降低,其掺量为10％、15％时,水泥的28 d、90 d抗压强度超过普通硅酸盐水泥.在3 d至90 d龄期内,水泥孔溶液pH值随龄期增长而逐渐增大.在相同龄期时,随着改性磷石膏掺量的增大,水泥孔溶液pH值减小,水化放热峰出现时间延缓.微观分析表明,掺入改性磷石膏后,28 d龄期时的水泥水化产物主要为钙矾石和C-S-H凝胶,水化产物的生成量在改性磷石膏掺量为15％时最多.

Effect of Modified Phosphogypsum on the Hydration Process of Gypsum Slag Cement

Gypsum slag cement was produced by mixing modified phosphogypsum ( 5％-25％ in mass ) , Portland cement clinker (15％in mass)and slag(60％-80％in mass).The compressive strength, heat of hydration , pH value of pore solution and hydration products of the gypsum slag cement were investigated .The results show that the compressive strength of the gypsum slag cement at 3 d and 7 d decreased with the incorporation of phosphogypsum .When the content of phosphogypsum reached 10％and 15％, the compressive strength at 28 d and 90 d surpass that of the ordinary portland cement .The pH value of the pore solution increased with the increase of age from 3 d to 90 d.At the same age , the pH value of the pore solution decreased , the occurring time of the exothermic peak increases , with the increase of phosphogypsum .The hydration products at the age of 28 d are mainly ettringite and calcium silicate hydrate , and the amount of hydration products reach the most with 15％of phosphogypsum .