The pH influence on the index properties of clays

Gori, Umberto

doi:10.1007/bf02594954

Cited by 14 publications

(3 citation statements)

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“…The engineering properties of soils are significantly influenced by the chemical properties of the medium, termed as ''chemical-mechanical coupling'' [6]. Many studies have focused on the effects of acid rain on the engineering properties of different soils [6][7][8][9][10][11][12][13][14]. From the literature, it can be seen that the following chemical and physical processes may describe the effect of acid rain on soil [7,12]: (I) dissolution and leaching of cations or anions from soil based on their solubility at different pH values; (II) changes in surface electrical properties of the colloidal fraction of soil; (III) absorption of anions in acid rain such as SO 2À 4 , NO À 3 , and CO 2À 3 in the soil environment; and (IV) changes in diffuse double layer of clay fraction due to ion exchange and consequent changes in the van der Waals forces acting between the clay particles, which may result in a change in the engineering properties of soil affected by acid rain.…”

Section: Introductionmentioning

confidence: 99%

Long-Term Intruding Effects of Acid Rain on Engineering Properties of Primary and Secondary Kaolinite Clays

Bakhshipour

Asadi

Huat

et al. 2016

Int. J. of Geosynth. and Ground Eng.

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In this study, the effects of simulated acid rain (SAR) on the engineering properties of primary and secondary kaolinite clays (PK and SK) were investigated. Tests of consistency limit, compressive strength, compressibility, hydraulic conductivity, and compaction characteristics were conducted to investigate the changes in the physico-chemical and engineering properties of PK and SK clays after being exposed to SAR at different pH levels of 2, 3, 4, 5, and 5.6 and at different fluxes of SAR equivalent to precipitation for 1, 5, 10, and 20 years. In addition, scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX), zeta potential and atomic adsorption spectroscopy (AAS) studies were conducted to identify the underlying mechanisms involved. The results revealed that for both PK and SK, the low pH value of SAR and higher flux of SAR resulted in a reduction in soil strength, maximum dry density, and increased compressibility, hydraulic conductivity, liquid limit, and optimum moisture contents. The AAS tests confirmed that reduction of more traced elements in PK and SK specimens when they were infiltrated by the SAR. Also, the formation of relatively a weak structure was observed through the SEM tests. The sensitivity of the PK specimen was higher than that of the SK specimen for SAR intrusion.

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Section: Introductionmentioning

confidence: 99%

Long-Term Intruding Effects of Acid Rain on Engineering Properties of Primary and Secondary Kaolinite Clays

Bakhshipour

Asadi

Huat

et al. 2016

Int. J. of Geosynth. and Ground Eng.

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“…The incorporation of cement decreases the porosity in the pore microstructure of soil due to the bonding of particles [36,37]. However, the effects from different pH in various soil types are also important: strength increases with a higher pH [38,39]. Finally, the important parameter is the mineralogy and structure of soil: finegrained, medium-grained or coarse-grained [40].…”

Section: Introductionmentioning

confidence: 99%

Simplex Lattice Design and X-ray Diffraction for Analysis of Soil Structure: A Case of Cement-Stabilised Compacted Tills Reinforced with Steel Slag and Slaked Lime

Lindh

Lemenkova

2022

Electronics

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Evaluating the structure of soil prior to building construction is valuable in a large variety of geotechnical and civil engineering applications. To built an effective framework for assessing the strength of the stabilised soil, the presented workflow includes a complex approach of simplex lattice design and X-ray diffraction for the analysis of soil structure. Different from the traditional in situ measurements, we propose a statistical framework for effective decision-making on binder combination to stabilise soil collected in three localities of Southern Sweden—Bromölla Municipality (Skåne County), Petersborg (Östergötland County) and Örebro (Örebro County). A practical solution is presented that includes the evaluation of strength properties of various types of soil using ordinary Portland cement (OPC), slaked lime and steel slag as pure agents and blended binders. The specimens were collected in Southern Sweden and included sandy silty tills and clay till (clay content 6–18%). The preprocessing included the mineralogical analysis of mineral composition and soil structure by X-ray diffraction (XRD) and a sieve. The soil samples were fabricated, compacted, rammed, stabilised by six binder blends and assessed for uniaxial compressive strength (UCS). The moisture condition value (MCV) and water content tests were done for compacted soil and showed variation in the MCV values for different binders. The study determined the effects from binder blends on the UCS gain in three types of soil, measured on days 7, 28 and 90. Positive effects were noted from the steel slag/lime blends on the UCS gain in sandy silty tills. A steel slag/slaked lime mixed binder performed better compared to the pure binders. The effectiveness of the simplex lattice design was demonstrated in a series of ternary diagrams showing soil strength evaluated by adding the stabilising agents in different proportions.

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“…the proportion and grain-size distribution of calcium carbonate, the content and type of clay minerals and other phases, the size and distribution of pores, etc.) (Skempton & Hutchinson, 1969;Datta et al, 1982;Veniale, 1985;Hawkins et al, 1988;Tsiambaos, 1991;Gori 1994;Tsifoutidis, 1993;Kouki, 2006). Therefore the comprehensive study of these sediments is essential in assessing their behaviour before, during and after of underground, open cut excavations and/or infillings.…”

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confidence: 99%

Mineralogy and microfabrics of claybearing sediments of NE Peloponnese (Greece): indices for physical behaviour in civil engineering works

et al. 2012

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The mineralogical composition, microfabrics and geochemistry of a set of eight samples derived from a narrow area of NE Peloponnese (Greece), where engineering works are presently in progress, were investigated in this study. No important mineralogical differences were observed between the samples other than a variation in the proportions of the participating phases. Analyses reveal that these sediments consist mainly of carbonates (calcite, dolomite), quartz and feldspars (albite, orthoclase). Carbonate minerals exhibit a micritic texture and a high degree of cementation bonding. Phyllosilicates and clay minerals are also common, with smectite and mixed-layer smectite-chlorite being the prevailing phases, followed by chlorite and white mica (muscovite, illite). According to the physical properties measured on bulk samples, the samples were found to exhibit a low to medium expansion, low to intermediate plasticity, normal activity and brittle behaviour. The porosity does not exceed 46% and the organic matter ranges between 3.80 and 5.00%. The high degree of cementation, the dispersed appearance of clays, the small pores (<10 μm) and the common occurrence of smectite in a mixed-layer with chlorite are all favourable characteristics, positively influencing the sediment's stability for engineering constructions.

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The pH influence on the index properties of clays

Cited by 14 publications

References 9 publications

Long-Term Intruding Effects of Acid Rain on Engineering Properties of Primary and Secondary Kaolinite Clays

Long-Term Intruding Effects of Acid Rain on Engineering Properties of Primary and Secondary Kaolinite Clays

Simplex Lattice Design and X-ray Diffraction for Analysis of Soil Structure: A Case of Cement-Stabilised Compacted Tills Reinforced with Steel Slag and Slaked Lime

Mineralogy and microfabrics of claybearing sediments of NE Peloponnese (Greece): indices for physical behaviour in civil engineering works

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