高钙灰矿物改性及其复合水泥化学收缩机理

Mineral modification of high calcium fly ash and the shrinkage mechanism of the composite cement

研究了高钙灰矿物改性及其与钢渣和改性磷石膏等矿物复合后胶材90d的化学收缩变化,利用孔结构压汞实验分析孔最可几分布、平均孔径及孔隙率对化学收缩变化影响机理。试验结果表明:(1)50%高钙灰取代水泥,明显减小孔径,孔最可几分布为5.488E-02mm,但孔隙率为26.8360%,降低并不多,因而90天化学收缩较低;(2)50%高钙灰取代水泥并掺入改性磷石膏,孔隙率为27.2150%,降低并不多,但孔径明显减小,孔最可几分布为4.894E-02mm,因而90d化学收缩较未掺改性磷石膏试样高;(3)经过物理化学活性激发的高钙灰具有较好的水化活性,50%改性高钙灰取代水泥胶材,其24h内化学收缩率比100%水泥及50%原高钙灰取代水泥大,而90d时孔最可几分布为5.720E-02mm,孔隙率为23.1336%,化学收缩率比100%水泥小很多。

Modified high calcium fly ash and mixed the fly ash, steel slag and phosphogypsum to cement, then studied the 90 d chem- ical shrinkage of the composite cement. By bore structure experiment, analysed the influence of the most probable distribution, aver- age bore aperture and porosity on the chemical shrinkage. The results are as follows： （1） as 50% high calcium replaced the cement, the bore aperture decreased obviously and the most probable distribution was 5.488E-02 ram, although the porosity was almost un- changed which was 26.836 0%, so the cement chemical shrinkage of 90 d was low; （2） as 50% high calcium replaced the cement plus adding modified phosphogypsum, the situation was almost the same; （3） the modified high calcium had good hydraulic activation, when 50% modified high calcium fly ash replaced the cement, the 24 h chemical shrinkage was high than that of the adding 50% high calci- um fly ash and that of the cement, and as the most probable distribution of 90d was 5.720E-02 mm and the porosity was 23.133 6% which show that the chemical shrinkage was lower than that of the cement.