Effect of Consistency Limit on the Strength of Cement-Solidified Dredged Sludge: Modelling and Micro-Mechanism

Water

Shiquan Wang¹  Zhiyong Niu¹  Yuanyuan Ma¹  Shenzhen Li¹  Hongrui Ma¹  Shunmei Gong¹  Huajin Qin¹  Jiangshan Li²  Xingxing He³ 

[1] National Engineering Research Center of Coal Mine Water Hazard Controlling, School of Resources and Civil Engineering, Suzhou University, Suzhou 234000, China;State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China;State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, China;

关键词: cement solidified;    dredged sludge;    evolution model;    liquid index;    strength;   

DOI  :  10.3390/w14121959

来源: DOAJ

【 摘 要 】

The unconfined compressive strength (UCS) of sludge with different consistency limits solidified by cement was investigated. The results showed that under the condition of constant initial water content, a higher liquid index of soil resulted in higher UCS. A novel strength-evaluation model based on the ratio of the liquid index to the cement content was developed, and the prediction deviation of the model was within 30%. The influence mechanism of the consistency limit of sludge on the cement solidification was revealed by scanning electron microscopy, mercury intrusion porosimetry, X-ray diffractometer and thermogravimetric analysis. For the cement-solidified dredged sludge (CDS) with a lower liquid index, a large amount of hydrate was interlaced with each other and wrapped soil particles, promoting the formation of a dense structure. For the CDS with a higher liquid index, hydrates such as C-S-H and ettringite challenged each other to play the role of “cementing particles” and “filling pores”, resulting in the formation of the porous structure. The mineralogical analyses confirmed that more C-S-H gels and ettringites were generated in the CDS with a lower liquid index, but less calcite was formed due to its denser structure. In engineering applications, reducing the liquid index by adjusting the consistency limit can improve the strength performance of CDS.

【 授权许可】

Unknown