FI100093B - Förfarande för kemisk stabilisering av tungmetallhaltigt


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The SEM image of uncured lime treated soil containing 4% gypsum sample illustrates the formation of larger quantities and bush like morphology ettringite crystal within the voids/pores (Fig. 12a). Specimen cured for 28 days pronounces the formations of relatively small ettringite crystal within the pores ( Fig. 12 b). Tests at the microscopic level (porosimetry, XRD and SEM) are the key to better insight into the lime stabilization reactions of gypseous soils and the evolution of the geotechnical properties of these soils. Analyses of lime-treated gypseous soils revealed the formation of new hydrates (CSH) and (CAH) and also ettringite. However, lime-treated gypseous soil with the addition of a 30% fly ash content shows the increase in Al, Ca, and S ions, confirming the significant formation of ettringite crystals compared to specimens containing 10 and 20% fly ash. Mainly 6% lime has been used to treat the clay soil (Table 1) The formation of ettringite minerals in treated soils (Eqn.

Ettringite formation in lime treated soils

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The accelerated strength early is due to formation of compacted structure with growth of ettringite needles within voids. Step 2: Identify Soil and Climatic Characteristics Climatic Impact In order for the formation of ettringite and sulfate heave to occur, the reaction requires access to water. Climatic areas with high annual rainfall and humid conditions contribute to the potential for sulfate formation and in turn, sulfate induced heave. Water can gain access strength of soils treated with different proportions of lime were evaluated. Based on the experimental results it is observed that the liquid limit and plasticity reduces as lime content increases, swell and shrink characteristics decreases with lime content.

FI100093B - Förfarande för kemisk stabilisering av tungmetallhaltigt

It is also important to recognize that gypsum is not the only problematic mineral in soils. Pyrite (FeS2) is a sulfide mineral that alters to gypsum (CaSO4·2H2O) under the right conditions and creates similar problems. These soils are often treated with a lime or cement stabilizer to improve the relevant qualities.

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During mixing of lime, soil, and water, lime provides the required calcium needed for cation exchange and flocculation/agglomeration of clay particles. Stabilization of expansive soils using lime and cement additives have been used by practitioners over the years.

Formation and growth of the mineral Ettringite was reported as the cause of severe heaving in several pavement failures. The swelling distress observed in stabilized soils is found to be due to one or a combination of three separate mechanisms: (1) volumetric expansion during ettringite formation, (2) water movement triggered by a high osmotic suction caused by sulfate salts, and (3) the ability of the ettringite mineral to absorb water and contribute to the swelling process.
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Ettringite formation in lime treated soils

paste compressive strength somewhat in comparison with the not treated fibers and.

av J Albrektsson · 2011 · Citerat av 16 — Drop formation. 400.
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Ettringite formation in lime treated soils bokmässan fria tider
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saline soil or saline water. Dissolved salt Delayed ettringite formation appears when the concrete has been cured at high Thaumasite formation might occur when the concrete contains limestone aggregate or presence of salt is treated. reactor vessel, which contains all the fuel elements forming a reactor core release sufficient fission products to contaminate the soil around, except The following lectures in this course treat the phenomenology that decomposition of ettringite and the loss of water from part of the Siliceous Lime-siliceous Limestone.