Addition of Lime and Fly Ash to Improve Highway Subgrade Soils

Athanasopoulou, Antonia

doi:10.1061/(asce)mt.1943-5533.0000856

Cited by 50 publications

(11 citation statements)

References 4 publications

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“…Similar sensitivity occurs to the cement-fly ash-treated samples. As what occurred in earlier studies [10,16,21], the decreases of MDDs occur due to the lower specific gravity of the fly ash and the lime-the replacement of soil particles in a given volume by particles of fly ash or lime of lower specific gravity compared to that of the soil particles. It is noteworthy that the cement-fly ash-treated samples show interesting trends for the OMCs.…”

Section: Resultssupporting

confidence: 55%

“…For instance, for the cement-treated silt, the cement content falls in the choices of 3%, 6%, and 8%; for the cementfly ash-treated silt, the fly ash content increases from 7% to 15% with the cement content remaining unchanged at 3%, or from 6% to 30% with the cement content remaining unchanged at 6%. The chosen dosages were also designed into levels in line with those adopted in existing studies (e.g., [10,12,16]) and so help compare the test results.…”

Section: Methodsmentioning

confidence: 99%

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Strength and Stiffness of Stabilized Alluvial Silt under Frost Actions

Wang

Deng

Yang

2017

Advances in Materials Science and Engineering

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The Yellow River alluvial silt was stabilized into pavement base materials for cold regions. The stabilizing additives were cement, fly ash, and lime, which were included in a range of combinations and dosages when mixed with the silt. Freeze-thaw cyclic impacts were conducted on the treated samples to assess materials performance of withstanding the frost actions. The tests were conducted on samples cured for 7 days to up to 180 days. Test results show that the cement-fly ash-treated samples outperform the other two stabilization categories with respect to material strength and stiffness developed under both normal and frost conditions. Under the normal conditions, the material unconfined compressive (UC) strength rises to 3.0 MPa on day 28 depending on the cement and fly ash dosage used. If subjected to frost actions, the fly ash inclusions warrant a residual UC strength value of 1.3 MPa and above. The antifrost performance of the cement-fly ash-treated samples is related to thermal buffer capacity of the fly ash particles. Water adsorption and material soundness results agree with the strength and stiffness development. An optimal dosage was 3-6% for the cement and 0.3 for cement to fly ash mass ratio.

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Section: Resultssupporting

confidence: 55%

Section: Methodsmentioning

confidence: 99%

Strength and Stiffness of Stabilized Alluvial Silt under Frost Actions

Wang

Deng

Yang

2017

Advances in Materials Science and Engineering

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“…In contrast, increased amounts of binder produced an increase in cementitious materials and this lead to decreased liquid limits. References [32][33][34] have reported about increases in the liquid and plastic limit of soils after have been treated with various binder types.…”

Section: Introductionmentioning

confidence: 99%

A Comparative Evaluation of Cement and By-Product Petrit T in Soil Stabilization

et al. 2019

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This study presents a comparison between the effectiveness of adding low binder amounts of industrial by-product Petrit T as well as cement to modify and improve fine-grained soil. Binder amount was added by soil dry weight; cement at 1%, 2%, 4% and 7% and Petrit T at 2%, 4% and 7%. The unconfined compressive strength (UCS) was used as an indicator of soil strength. In addition, the consistency limits, laser particle size analysis, and pH tests were also conducted on the treated soil. The samples were cured at 20 • C for different periods from 7 to 90 days before testing. Results indicate that cement is more effective at improving the physical and engineering properties of the treated soil. Soil plasticity index decreases after treatment and with time. Liquidity index and the water content to plastic limit ratio are introduced as new indices to define the improvement in the workability of treated soil. Soil particle size distribution is changed by reducing the clay size fraction and increasing the silt size fraction after treatment. The findings confirm that adding small binder contents improve soil properties, which subsequently reduce the environmental threats and costs that are associated with using a high amount of binder. Enhanced soil strengths, reduced soil plasticity and swelling potential are the most desirable outcomes from the treatment. For certain soil stabilization applications, the cost of the binder itself could result in a considerable saving in the overall costs of the project [24]. Petrit T is a waste product from sponge iron production [18]. It is considered a cheap by-product material [25]. Therefore, in order to decrease the environmental impact and costs, finding new binders as alternatives to Portland cement is important. Thus, there is a need to compare the effectiveness of using cement and by-product Petrit T as stabilizing agents.This paper presents a comparative evaluation between using Portland cement and by product Petrit T to enhance the physical and mechanical properties of sandy clayey silt soil. An extensive experimental program was carried out in this study, including tests of unconfined compressive strength, laser particle size, consistency limits, and pH tests, using various binder amounts and curing periods. Materials and MethodsThe samples used in this study were prepared from a natural soil from Gothenburg, south west coast of Sweden. The soil consists of 55% silt, 29% fine sand and 16% clay. The natural water content is 30%, the liquid limit 37% and the plastic limit 20%. The optimal moisture content is 12%, and the proctor density is 1.97 t/m 3 . The ignition test showed that the soil has 4% organic content. Therefore, according to the Swedish standard, natural soil is classified as sandy clayey silt (saclSi) with low organic content [26][27][28].Natural soil was firstly homogenized and then mixed with Petrit T as well as the cement in various percentage from 1 to 7% as dry mass of soil and cured for 7, 14, 28, 60 and 90 days before testing.Unconfined compressive tests (U...

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“…The admixture of lime caused an increase in the plastic limit, while both the liquid limit and the plasticity index of the soils have been reduced. The immediate effect of lime addition to the soil is to cause flocculation and agglomeration of the clay particles due to cation exchange at the surface of the soil particles (Athanasopoulou, 2014). The result of this short-term reaction is to enhance workability and plasticity.…”

Section: Resultsmentioning

confidence: 99%