Influence of Organic Matter on the Strength Properties of Artificially Stabilized Sands-PPT Presentation

PPT Presentation

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The study examines how organic matter affects cement hydration and strength development in artificially stabilized sandy soils, with the aim of improving the assessment of deep soil mixing (DSM) suitability where organic content is significant.<br /><br />Laboratory testing compared sands treated with several cement types and binder contents. The researchers also investigated how different organic soils and their components influence curing and hardening. The presentation identifies humic and non-humic matter, decomposition, water content, and fibre content as potentially relevant factors.<br /><br />The results indicate that organic matter can inhibit the formation of calcium-silicate-hydrate (C-S-H) phases and pozzolanic reactions. Organic contents of approximately 5–8% may substantially reduce the compressive strength of cement-stabilized soil. In the tested soils, 250–350 kg/m³ of CEM I produced a considerable strength increase. Strength results became more variable at higher organic contents, possibly because organic matter is heterogeneous and sample preparation affects outcomes. Measurements of sample pH before and after curing did not yield conclusive findings.<br /><br />Ongoing work aims to identify the key physico-chemical processes, quantify humic components such as humic and fulvic acids using different testing methods, and develop practical guidance for assessing and treating organic soils.

Keywords

organic matter

cement hydration

deep soil mixing

sandy soils

compressive strength

C-S-H phases

pozzolanic reactions

humic acids

organic soils

soil stabilization