摘要
中国每年产出大量钢材,伴随而产生的副产品钢渣,因其利用率低而导致资源浪费和环境污染。为充分、高效地再生利用废弃钢渣,从提升钢渣的胶凝性出发,参考水泥组分的率值控制指标,采用偏高岭土对钢渣进行成分增补,以提高Al_2O_3和SiO_2含量,开展水玻璃的硅系激发及水泥的复合系激发试验,制备得到钢渣型复合基材。净浆一定龄期后进行无侧限抗压强度试验,并尝试引入率值这一参数评价钢渣基材性能。结果表明:当水泥、偏高岭土和钢渣之间最优质量配比为50∶15∶85,水胶比为0.28时,复合基材的90 d强度可达41.5 MPa。复合系与钙系钢渣型基材的率值高度一致,可为不同初始成分的钢渣基材的标准化制备提供参考。采用XRD,SEM,MIP等多种微观测试技术探讨钢渣基材强度形成机理,发现钢渣基材水化产物为C-H,C-(A)-S-H和C-A-H等,其中网状C-S-H最为发育,各部分紧密联结,大孔隙减少,使得钢渣复合基材强度保持稳定增长。将钢渣基材用于软土加固中,当钢渣基材掺量为20%时,固化软土28 d龄期无侧限抗压强度可达1.2 MPa。固化土强度与似水灰比R成反比,给出了可用于预测钢渣基材固化土强度预测的经验表达式。
A large amount of steel slag is produced annually in China,but it is not utilized efficiently owing to the low cementation.For the potential cementation of steel slag,composition adjustment and activation of steel slag were performed to enrich the active Al2O3 and SiO2 content by considering the slag's composition and referring the clinker component.Based on the investigation of the previous Ca(OH)2-based activation,Na2SiO4-based and cement-based activation were attempted. At the optimal mass proportion of the steel slag composite (cement :metakaolin :slag equal to 50:15:85),its strength after 90days of curing and with a 0.28water-binder ratio was 41.5MPa. Clinker moduli were tentatively introduced to evaluate the performance of the composite,and the moduli of the composite activated by cement and lime were similar,suggesting a reference method for the standard preparation of the slag-based composite with different initial components. Microscopic techniques were adopted to clarify the strength generation mechanism,including the porosity,type,and pattern of the hydrated products.The results show that the hydration products of cement-based excitation are composed of C-H,C-(A)-S-H,C-A-H and C-S-H,etc., and the main product is the reticular C-S-H,which fulfilled and connected the hydration matrix. The prolific hydration product as well as the smaller capillary pore size leads to the strength continuous generation.After 28days of curing,the strength of the soft soil stabilized by slag composites activated by cement at the optimal ratio is 1.2MPa with 20% incorporation. Furthermore,its strength reduces with the increase in moisture content.The strength of the stabilized soft clays is a function of the quasi water/agent ratio,and a prediction method is proposed.
作者
邓永锋
赵余
刘倩雯
顾兴宇
查甫生
朱春东
DENG Yong-feng;ZHAO Yu;LIU Qian-wen;GU Xing-yu;ZHA Fu-sheng;ZHU Chun-dong(School of Transportation,Southeast University,Nanjing 210096,Jiangsu,Chinal;JSTI Group,Naniing 210017,Jiangsu,China;Department of Civil,Construction,and Environmental Engineering,North Carolina State University,Raleigh NC27616,North Carolina,USA;School of Resources and Environmental Engineering,Hefei University of Technology,Hefei 230009,Anhui,China;Jiaxing Highway Administration,Jiaxing 314001,Zhejiang,China)
出处
《中国公路学报》
EI
CAS
CSCD
北大核心
2018年第11期11-20,共10页
China Journal of Highway and Transport
基金
国家自然科学基金项目(41572280
51878159
41672306)
关键词
道路工程
固化软土
硅系与复合系激发试验
钢渣
强度形成
微观结构
road engineering
soft soil stabilization
Na2SiO4-and cement-based activation test
steel slag
strength generation
microstructure
