摘要
研究了几种化学物质对碱-矿渣水泥凝结时间的延缓效果和对强度发展的影响。结果表明:几种可溶性锌盐(硝酸锌、硫酸锌和氯化锌)和硝酸钡对碱-矿渣水泥的凝结具有显著的延缓作用,并且对其强度发展副作用较小,0.5%掺量时对水泥强度发展甚至有促进作用;明矾、硫酸铵、磷酸、丙三醇和醋酸钠对碱-矿渣水泥也有一定的缓凝作用,但对水泥强度有较大副作用,掺量越大副作用也越大;磷酸钠、氯化铁、氧化锌和草酸钾、三乙醇胺、乳酸对碱-矿渣水泥缓凝作用甚微,甚至还出现促凝效果;碱-矿渣水泥水化体系中引入可溶性锌盐物质和硝酸钡可能在水化初期于激发剂组分或矿渣解离释放出的OH-离子或[SiO4]4-离子反应形成尺寸细小的难溶性沉淀物质并覆盖于矿渣粉颗粒的表面,阻碍激发剂组分与矿渣表面的进一步反应,从而导致浆体凝结延缓。
Effectiveness of several chemical substances for the retardation of setting of alkali-activated slag cement and its influence on the strength development were investigated.Results shows that addition of some soluble zinc slats,i.e.zinc sulfate,zinc chloride or zinc nitrate,or barium nitrate retards the setting of alkali-activated slag cement significantly with less side effect on its strength development,which is even enhanced when the dosage is below 0.5%,while addition of alum,ammonium sulfate,phosphorus acid,C3H8O3,or sodium acetate also retards the setting of alkali-activated slag cement in some extent but with obvious side effect on its strength development,and the more the addition the more the side effect is,whereas addition of sodium phosphate,iron chloride,zinc oxide,potassium oxalate,triethanolamine,or lactic acid hardly retards the setting of alkali-activated slag cement even accelerates its setting instead.It is believed that the introduced soluble zinc slats or barium nitrate into alkali-activated slag cement-water system may reacts with some anions like OH^-or [SiO4]^4-released from alkali activator or the dissolution of slag particles at early stage of hydration to form some insoluble precipitates with small size,which then sticks and covers the surface of the slag particles and prevent the further reaction of the activator with the slag surface,therefore,results the prolonged setting of the cement paste.
出处
《混凝土》
CAS
CSCD
北大核心
2010年第9期68-70,73,共4页
Concrete
基金
国家973项目资助(2009CB623104)
关键词
碱
矿渣
水泥
凝结
强度
alkali
slag
cement
setting
strength
