摘要
磷石膏基超硫酸盐水泥(PSSC)水化时存在体积胀缩行为,这种行为对工程建筑的稳定性是否产生不利影响尚不明确,因此明晰该行为的产生机制至关重要.为探究PSSC的胀缩机制,开展了“恒体积法”膨胀力、体积胀缩量、水化热、X射线衍射(XRD)、扫描电镜(SEM)试验,研究水化热、失水率、各水化产物的含量、水化物的晶体形态对体积胀缩的影响;通过汞孔隙法(MIP)进一步揭示胀缩行为对结构孔隙的影响.结果表明:水化前期,水化温度急剧上升,水化产物中钙矾石呈放射状生长,引起PSSC迅速膨胀;水化中期,PSSC的膨胀速率随着钙矾石生成速率的减缓而降低;水化后期,PSSC体系的持续失水导致其体积略有回缩.MIP结果进一步证明,胀缩行为使得孔隙结构更加密实.
The volume expansion and contraction behavior observed during the hydration of phosphogypsum-based super-sulfate cement(PSSC)remains unclear in terms of its potential adverse effects on the stability of engineering structures.Therefore,it is very important to clarify the mechanisms underlying this behavior.In order to investigate the expansion and shrinkage mechanism of PSSC,the expansion force test which carried out by the"constant volume method",volume expansion and shrinkage test,heat of hydration test,X-ray diffraction(XRD)and scanning electron microscopy(SEM),which revealed the effects of heat of hydration,water loss,content of each hydration product and hydrate crystal morphology on the volume expansion and shrinkage.The effects of volume expansion and contraction on the structural porosity were investigated by mercury intrusion porosimetry(MIP)and SEM.The results show that:the large amount of heat of hydration and the radially growing ettringite in the hydration products caused the rapid expansion of PSSC in the early stage of hydration;the slow generation of ettringite lead to the less expansion of PSSC in the middle stage of hydration;the continuous loss of water in the late stage of hydration led to the shrinkage of the PSSC;and the expansion and shrinkage behaviors resulted in the more compact of the pore structure.
作者
潘正午
陈友伦
吴军
谈云志
PAN Zhengwu;CHEN Youlun;WU Jun;TAN Yunzhi(The Institute of Problematic Soils Mechanics,China Three Gorges Univ.,Yichang 443002,China;Yichang Key Laboratory of the Resources Utilization for Problematic Soils,China Three Georges Univ.,Yichang 443002,China;College of Civil Engineering&Architecture,China Three Gorges Univ.,Yichang 443002,China)
出处
《三峡大学学报（自然科学版）》
CAS
2023年第6期63-69,共7页
Journal of China Three Gorges University：Natural Sciences
基金
国家自然科学基金(52209136)
长江水利委员会长江科学院开放基金(CKWV2021871/KY)。
关键词
超硫酸盐水泥
磷石膏
水化产物
膨胀
钙矾石
晶体形态
super-sulfated cement
phosphogypsum
hydration products
expansion
ettringite
crystal morphology
