摘要
铝土矿开采过程中会产生大量固体废渣。为解决铝土矿废渣的排放与堆积难题,促进固体废弃物资源化利用,通过将不同掺量的铝土矿废渣添加到砂浆中以制备改性混凝土。对掺铝土矿渣混凝土开展无侧限压缩试验、计算机层析(CT)扫描试验和扫描电镜试验,探究其压缩特征与微观结构。试验结果表明:掺铝土矿渣混凝土的抗压强度和弹性模量随铝土矿渣掺量的增加呈先提高后下降的变化趋势,当铝土矿渣掺量为15%时,试件的无侧限抗压强度与弹性模量最高;由CT扫描获取了混凝土细观结构的二维图像,从中发现随着铝土矿渣掺量增加,试件内孔隙数量和尺寸逐渐减小,由CT图像计算的混凝土孔隙率与抗压强度保持负相关的线性关系;掺加铝土矿渣促进了水泥的二次水化反应,引起水泥砂浆中的Ca(OH)2含量降低,水化硅酸钙含量提高,进而使得骨料间裂隙发生闭合,混凝土的力学性能得到提升。
A large amount of solid waste residues are produced in the process of bauxite mining. In order to solve the problem of discharge and accumulation of bauxite waste residues and promote the recycling of solid waste resources, the modified concrete was prepared by adding different amounts of bauxite waste residues to mortar. Unconfined compression test, computer tomography(CT) scanning test and scanning electron microscope test were carried out to investigate the compression characteristics and microstructure of bauxite slag concrete. The test results show that the compressive strength and elastic modulus of concrete with bauxite slag increase first and then decrease with the increase of bauxite slag content. When the content of bauxite slag is 15%, the unconfined compressive strength and elastic modulus of the specimen are the highest. The two-dimensional image of concrete meso-structure was obtained by CT scanning. It is found that with the increase of bauxite slag content, the number and size of pores in the specimen gradually decrease, and the concrete porosity calculated by CT image maintains a negative linear relationship with the compressive strength. The doping modification of bauxite slag can promote the secondary hydration reaction of cement, which causes the content of Ca(OH)2in cement mortar to decrease and the content of calcium silicate hydrate to increase, thus closing the cracks between aggregates and improving the mechanical properties of concrete.
作者
周春煦
赵立财
朱俊高
ZHOU Chunxu;ZHAO Licai;ZHU Jungao(Jiangsu Shipping College,Nantong,Jiangsu 226010,China;State Key Laboratory of Hydraulic Engineering Simulation and Safety,Tianjin University,Tianjin 300354,China;Hohai University,Nanjing,Jiangsu 210024,China)
出处
《矿业研究与开发》
CAS
北大核心
2023年第2期70-75,共6页
Mining Research and Development
基金
国家自然科学基金项目(52078169)
江苏省高职院校教师专业带头人高端研修项目(2021GRGDYX007)
江苏高校“青蓝工程”优秀青年骨干教师培养项目(2020QLGC)
南通市科技计划项目(MSZ2022197)。
关键词
生态混凝土
铝土矿渣
微观结构
力学性能
机理分析
Eco-concrete
Aluminum slag
Microstructure
Mechanical property
Mechanism analysis
