SO3对脱硫石膏-偏高岭土-水泥复合胶凝体系性能的影响

摘要

对脱硫石膏-偏高岭土-水泥复合胶凝体系性能进行研究.结果表明:复合胶凝体系净浆的初凝和终凝时间较纯水泥净浆延长,但初凝和终凝的时间间隔较短;复合胶凝体系胶砂试样的流动度与基准组相似;随着养护龄期的增加,试样抗压强度不断增加;SO3与Al2O3摩尔比为1.0∶1.0时试样的抗压强度较高;复合胶凝体系胶砂试样呈现膨胀,但膨胀率不超过0.39％;试样28 d抗压强度与膨胀率的发展规律一致,即AFt生成量和生成速率较高者,其28 d膨胀率也较高且抗压强度发展较理想;水化产物中同时存在AFt和C-A-H,水化后期少量AFt中的Al3++被Si4+取代,转化成AFm.%Flue gas desulphurization gypsum(FGD)-metakaolin(MK)-cement system were prepared and investigated.Results show that compared with the pure cement paste,initial and final setting time of the compound system are much longer,the period between initial and final setting time is much shorter.Fluidity of the compound system is at the same level of pure cement paste.Compressive strength of the samples increases with increasing curing age,and compressive strength of the sample with SO3 to Al2O3 molar ratio of 1.0 ∶ 1.0 is the highest.The samples show a little expansion but not beyond 0.39％.The compressive strength development law of the samples cured for 28 d is consistent with expansion ratio.It means that more formation content and higher formation rate of AFt contribute to higher expansion and ideal compressive strength.The hydration products include AFt and C-A-H at the same time.A few AFt transforms into AFm replacing Al3+ by Si4+ in later hydration period.