磷渣-水泥复合及碱磷渣胶凝材料力学性能实验研究

Mechanical Properties of Phosphorus Slag-Portland Cement Composite and Alkali Phosphorus Slag Cementitious Materials

采用磷渣以20%、40%和60%的比例取代水泥制备磷渣-水泥复合胶凝体系(PSC-x)以及用浓度分别为6 mol/L、8 mol/L、10 mol/L和12 mol/L的NaOH溶液制备碱激发磷渣胶凝体系(PSA-x)。测试了两种体系的标准稠度用水(NaOH溶液)量、凝结时间、胶砂抗折强度和抗压强度,并结合XRD、TG-DSC和SEM-EDS等技术手段对其进行了物相组成及微观形貌的分析观测。研究结果发现:磷渣的掺入使PSC-x体系的标准稠度用水量降低了13.6%左右。而凝结时间却明显延长。增加NaOH溶液的浓度,PSA-x体系的标准稠度用液量也随之增加,且均高于PSC-x体系。凝结时间则较PSC-x体系明显缩短。适量掺入磷渣,能明显提高水泥胶砂试件的抗压强度;PSA-x体系的抗压强度发展良好,其强度值随激发剂浓度提高而呈下降趋势。PSC-x体系主要有Ca(OH)2、C-S-H凝胶、AFt和C4AHx等水化产物,而PSA-x体系则是Ⅰ型C-S-H凝胶,还有一定量的方沸石存在。

Phosphorus slag was used to replace cement by 20%, 40% and 60% to prepare phosphorus slag-Portland cement composite system(PSC-x). In addition, NaOH solution with concentrations of 6 mol/L, 8 mol/L, 10 mol/L and 12 mol/L was used to prepare alkali-activated phosphorus slag system(PSA-x). Water(NaOH solution) requirement for standard consistency, setting times, flexural and compressive strengths of mortar specimens of the two systems were tested. Hydration products and microstructure of the two systems were also analyzed and observed by XRD, TG/DSC and SEM-EDS techniques. The results show that the addition of phosphorous slag reduces the water requirement for standard consistency of PSC-x system by about 13.6%, and the setting time is obviously prolonged. NaOH solution requirement for standard consistency of PSA-x system increases with the increase of NaOH solution concentration, which is higher than that of PSC-x system. Setting time of the former is also obviously shorter compared to the latter. The addition of phosphorous slag is good to improve the compressive strength of the mortar specimens. PSA-x system also has a good development in compressive strength, and the strength decreased with the increase of activator concentration. The main hydration products of PSC-x system are Ca(OH)2, C-S-H gel, AFt and C4AHx, while the main hydration product of PSA-x system is type I C-S-H gel. A certain amount of analcite is also observed in PSA-x system.