Abstract

Dredging works are essential to ensure navigability in Harbors and waterways. However, this crucial activity generates millions of tonnes of waste each year worldwide. Since the disposal of dredged material is responsible for several environmental impacts, entrepreneurs and engineers must find creative uses for it. Therefore, this study aims to characterize a local dredged material to assess its properties and suitability for geotechnical applications. With this knowledge, this paper presents a series of experimental tests on dredged material samples retrieved from Rio Grande's Port, Brazil. The experimental program includes determining Atterberg limits, sieve and sedimentation analysis, pH and SEM analysis, compaction curve, and unconfined compressive strength in a reconstituted state. The results showed that the material is sandy lean clay, with unfavourable strength characteristics for geotechnical work in a raw state. However, with the advent of chemical stabilization techniques, there is potential for enhancing its suitability for geotechnical applications. By exploring methods such as adding binders like lime or Portland cement, the material's strength and stability could be significantly improved, opening up possibilities for its utilization in various engineering projects. This study contributes valuable insights into the potential reclamation and beneficial reuse of dredged material, ultimately aiding in the sustainable management of harbor and waterway dredging operations

Abstract

Reducing the extraction of natural resources is a current demand in the construction industry. Studies show that eggshells are rich in calcium carbonate and have the potential to replace limestone in lime production. In this context, the objective of this article is to use an eggshell lime produced in the laboratory to stabilize a residual clayey soil and compare the unconfined strength of the admixtures with others using commercial dolomitic lime. Different lime contents and porosities were evaluated and the porosity/lime ratio was studied to understand the unconfined strength behavior of admixtures. In addition to the soil and limes characterization tests, X-ray diffraction tests were carried out to analyze the chemical and mineralogical composition of the materials. The results showed that increasing lime content and decreasing porosity increased unconfined strength. Also, the unconfined strength achieved with the eggshell lime was greater than that achieved with dolomitic lime for the same lime content. The X-ray diffraction tests showed that the eggshell lime is composed almost entirely of calcium hydroxide, and microscopic images demonstrated much stronger bonds in the final product obtained from eggshell lime. The porosity/lime ratio was a good parameter for evaluating unconfined strength. A unique relationship was achieved linking unconfined compressive strength with the porosity/lime ratio for both the eggshell and the dolomitic lime mixtures.