海水与矿物掺合料对水泥基材料微结构和力学性能的影响  

Influence of Seawater and Mineral Admixtures on Microstructure and Mechanical Performance of Cement-Based Materials

作　　者：朱德举[1,2] 赵雪薇 郭帅成 ZHU Deju;ZHAO Xuewei;GUO Shuaicheng(College of Civil Engineering,Hunan University,Changsha 410082,China;Key Laboratory for Green&Advanced Civil Engineering Materials and Application Technology of Hunan Province,Hunan University,Changsha 410082,China)

机构地区：[1]湖南大学土木工程学院,长沙410082 [2]湖南大学绿色先进土木工程材料及应用技术湖南省重点实验室,长沙410082

出　　处：《硅酸盐学报》2024年第5期1477-1485,共9页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金项目(U1806225,52208246,U22A20122);湖南省自然科学基金项目(2023JJ40142);长沙市自然科学基金项目(kq2202160);中央高校基本科研业务费项目(531118010493)。

摘　　要：海水中多元离子会通过参与水化反应改变水泥水化产物组分和微结构,从而影响其力学性能和耐久性。本工作通过对孔溶液离子成分测试和水化产物矿相表征以揭示海水中多元离子与矿物掺合料耦合作用下,水泥基材料微结构和力学性能演化机制。采用离子色谱仪及电感耦合等离子发射光谱仪测得压滤法获得的净浆孔溶液的离子成分,同时结合X射线衍射、热重分析等微观表征研究水化产物矿相的演变规律。结果表明:海水中多元离子会促进水泥中硅酸三钙和硅酸二钙的水化,提高海水净浆孔溶液碱度,加快矿物掺合料与氢氧化钙的二次水化反应。硅灰对于孔溶液碱度的降低效果显著优于粉煤灰,也能通过生成更多水化硅酸钙凝胶实现钠离子和钾离子的有效固化。粉煤灰可以通过促进钙矾石、Friedel’s盐等铝相产物生成,实现对氯离子的有效固化,同时固化效果优于硅灰。本工作可以为海水海砂混凝土微结构和力学性能调控提供参考。Introduction The utilization of seawater and sea sand for concrete production can effectively relieve the environmental pressure caused by the consumption of freshwater and river sand resources.Previous studies demonstrate that the mechanical properties of seawater sea sand concrete are consistent with those of normal concrete,which can meet the construction needs.However,the multiple element ions in seawater alternate the components and microstructure of hydration products via participating in the hydration reaction,affecting its durability performance.Mineral admixtures can be used to mitigate the possible adverse effects of multiple element ions on cementitious materials.The existing research on the interaction between inorganic ions and the internal microenvironment of cementitious materials mainly focus on the effect of single ions,and the influence mechanism of multiple element ions lacks systematic investigations.Meanwhile,the influence mechanism of mineral admixtures on the performances of seawater sea sand concrete Is still unclear.In this paper,the pore solution composition and the mineral phases of the hydration products were characterized to reveal the evolution mechanism of the internal microenvironment under the coupling effect of multiple element ions in seawater and mineral admixtures.Methods A cementitious system was designed via the centroid simplex optimization of Portland cement,fly ash and silica fume.The artificial seawater was prepared according to the standard(ASTM D1141-98)at a p H value of 8.29.Sea sand from Jiaozhou Bay,China,was used as fine aggregates with a fineness modulus of 2.65.The polycarboxylic acid high-performance water reducer with a water reduction rate of 30%was used to adjust the flowability of fresh stage cement paste,(Shanxi Feike New Material Science and Technology Co.Ltd.,China).The specimens with a water/binder ratio of 0.35 and a sand/binder ratio of 1.0 were then prepared for characterization,and the water-reducing agent dosage was adjusted to maintain the same flu

关 键 词：海水海砂混凝土 孔溶液 水化产物 矿物掺合料 

分 类 号：TU528[建筑科学—建筑技术科学]