复合型外加剂对碱式硫酸镁水泥强度研究  

Study on composite admixture to strength of basic magnesium sulfate cement

作　　者：孙航 黄世麟 李青[1] 李利军[1] SUN Hang;HUANG Shilin;LI Qing;LI Lijun(School of Civil Engineering and Architecture,Liuzhou 545006,China)

机构地区：[1]广西科技大学土木建筑工程学院,广西柳州545006

出　　处：《广西科技大学学报》2018年第2期15-22,共8页Journal of Guangxi University of Science and Technology

基　　金：国家自然科学基金项目(31560466);广西自然科学基金项目(2016GXNSFAA380108)资助

摘　　要：碱式硫酸镁水泥作为一种轻质高强、节能环保的新型镁质胶凝材料,外加剂对它起着至关重要的作用.本文使用有机酸A分别与不同的强碱弱酸盐B、C配制了复合型外加剂,研究了不同外加剂及外加剂用量对碱式硫酸镁水泥抗折、抗压强度的影响,得到两种较为优秀的复合型外加剂AB3、AC5,并结合SEM及XRD进行表征.结果表明:当AB3、AC5掺量为轻烧氧化镁质量的0.2%时,可比未掺加外加剂的试件28 d抗折强度提高300%以上,抗压强度提高120%以上.复合型外加剂AB3、AC5用量的增加均会降低碱式硫酸镁水泥的早期强度,但后期强度有所提高,AC5比AB3型外加剂更能使碱式硫酸镁水泥形成较高的早期强度,掺加AC5型外加剂的试件28 d抗折强度较高,掺加AB3型外加剂的试件28 d抗压强度较高,复合型外加剂兼具了不同的络合与调节溶液pH的作用,为碱式硫酸镁水泥的推广应用提供了更多选择性.Magnesium sulfate basic cement is a light-weight,high-strength and new type energy-saving magnesia cementitious material.And admixture is important for it.In this paper,using organic acid A and different weakacid salts B,C to prepare composite admixture respectively,the effects of different kinds and dosages of admixtures on the flexural strength and compressive strength of basic magnesium sulfate cement were studied.Two kinds of excellent composite admixtures AB3 and AC5 were obtained,then SEM and XRD were used to characterize.The results show that when the content of AB3 and AC5 is 0.2%of the mass fraction of light-burned magnesium oxide,the flexural strength of 28 d can be increased by more than 300%,and the compressive strength can be increased by more than 120%.With the increase of dosages of composite admixtures AB3 and AC5,the early strength of basic magnesium sulfate cement will be reduced,but the later strength will be improved,the composite admixture AC5 can make the basic magnesium sulfate cement form higher early strength than AB3,the flexural strength of 28 d with AC5 is higher,and the compressive strength of 28 d with AB3 is higher,composite admixtures have different functions of complexing and regulating the solution pH,which provides more selectivity for the popularization and application of basic magnesium sulfate cement.

关 键 词：碱式硫酸镁水泥 外加剂 复合 强度 SEM XRD 

分 类 号：TQ172.4[化学工程—水泥工业]