Ba2+对过硫磷石膏胶凝材料性能的影响研究

Effect of Ba2+ on Properties of Excess-Sulfate Phosphogypsum Cementitious Materials

原状磷石膏经过干燥、过筛处理后,按磷石膏∶矿粉∶P·O 52.5水泥∶生石灰=50%∶40%∶5%∶5%的质量比制备过硫磷石膏胶凝材料(EPGC)。采用加入不同量氯化钡的方法来探究Ba^2+对EPGC的力学性能、孔结构和体积稳定性的影响。研究结果表明:随着氯化钡单掺和氯化钡-水玻璃复掺掺量的增加,EPGC硬化体强度先增大后减小,线膨胀率先减小后增大。当氯化钡的掺入量为18wt%时,试样28 d强度达到32.8 MPa,孔隙率为15.2%,28 d和56 d线膨胀率为0.032%和0.083%,与空白对比组相比,强度增长了60.0%,孔隙率降低了36.9%,28 d和56 d线膨胀率分别降低了64.44%和51.18%。当氯化钡和水玻璃按质量比1∶1复合掺入量为16wt%时,试样28 d抗压强度最大达到38.1 MPa,孔隙率为12.5%,28 d和56 d线膨胀率为0.028%和0.076%,与空白对比组相比,强度增长了84.6%,孔隙率降低了48.0%,28 d和56 d线膨胀率分别降低了68.89%和55.29%。

In terms of mass percentage of phosphogypsum∶slag powder∶P·O 52.5 cement∶quicklime=50%∶40%∶5%∶5%,excess-sulfate phosphogypsum cementitious material(EPGC)was prepared after the original phosphogypsum was dried and sieved.The influence of Ba^2+on the mechanical properties,pore structure,and volume stability of EPGC were investigated by adding different amounts of BaCl 2.The test results show that with the increase of content of barium chloride as single admixture and barium chloride-sodiun silicate as compound admixture,the strength of the hardened body of EPGC increases first and then decreases,and the linear expansion rate decreases first and then increases.When the content of barium chloride is 18wt%,the compressive strength of the sample at 28 d is 32.8 MPa,the porosity is 15.2%,the linear expansion rate at 28 d and 56 d are 0.032%and 0.083%respectively.Compared with the control group,the compressive strength increases 60.0%,porosity decreases 36.9%,linear expansion rate at 28 d and 56 d decrease 64.44%and 51.18%respectively.When the content of barium chloride and sodium silicate are both 16wt%by mass ratio of 1∶1,the compressive strength of the sample at 28 d reaches 38.1 MPa,the porosity is 12.5%,linear expansion rate at 28 d and 56 d are 0.028%and 0.076%respectively.Compared with the control group,the compressive strength increases 84.6%,porosity decreases 48.0%,linear expansion rate at 28 d and 56 d decrease 68.89%and 55.29%respectively.