In China, contamination of soils by heavy metals becomes a pressing problem. The
urgency to remediate heavy metals contaminated soils creates an ever increasing
demand for environmental protection and ecological civilization construction.
Solidification/Stabilization (S/S) has been widely applied in the remediation of
heavy metal-contaminated soil worldwide because of its effectiveness, low cost, and
easy handling. Besides, the S/S products could also be utilized as subgrade or
roadbed filling materials. The S/S treatment of heavy metal-contaminated soil
involves interactions between soils, heavy metals, and binders. Soil properties and
hydration reaction of binder are influenced by the presence of heavy metals.
Meanwhile, heavy metal speciation and effectiveness of binder are, in turn,
dependent on soil properties. Especially, the existing hydration products can
improve the effectiveness of heavy metal precipitation and engineering properties of
S/S products by changing the structure of heavy metal-contaminated soil. It is quite
difficult to quantitatively predict the long-term structure variation of S/S products
due to the lack of knowledge about the interaction mechanisms between soils,
heavy metals, and binders. As a result, utilization of S/S-treated heavy contaminated soil is rather limited. Therefore, solving engineering problems and recycling of soil necessitate a systematic study on the structure evolution mechanisms of heavy metal-contaminated soils treated by S/S.
Various research methods, such as experimental study, theoretical analysis, and
numerical simulation, were employed in this book to dissect the evolution mechanisms of structural characteristics of Pb-contaminated soils during the S/S process. A combination of laboratory and field tests, assisted by XRD, MIP, SEM, and many other technologies, was adopted in an attempt to establish the structural characteristics of Pb-contaminated soil on both the macroscopic and microscopic scales. Meanwhile, the influence of laws on the S/S process and their internal mechanisms were systematically analyzed. Models for the strength prediction and Pb leaching prediction of S/S monolith were established, which could provide key theoretical
guidance and parameter support for the design of S/S remediation of Pb-contaminated soil and recycling.