Geotechnical and Geological Engineering

, Volume 26, Issue 2, pp 121–132

Comparison of Methods for Determining Specific-surface Area of Fine-grained Soils

  • D. N. Arnepalli
  • S. Shanthakumar
  • B. Hanumantha Rao
  • D. N. Singh
Original Paper

DOI: 10.1007/s10706-007-9152-5

Cite this article as:
Arnepalli, D.N., Shanthakumar, S., Hanumantha Rao, B. et al. Geotech Geol Eng (2008) 26: 121. doi:10.1007/s10706-007-9152-5

Abstract

Characteristics of fine-grained soils primarily depend on their specific-surface area and hence, reliable determination of this parameter is essential. In this context, researchers have employed quite sophisticated instruments (viz., a BET surface area analyzer, the mercury intrusion porosimetry, internal reflectance spectroscopy, X-Ray diffraction and gas pycnometer etc.) and methodologies (viz., sorption of Methylene Blue dye, Ethylene Glycol Monoethyl Ether and p-Nitrophenol) to determine specific-surface area of these soils. However, most of these methodologies are found to be quite tedious, cost and time intensive. Apart from this, the results obtained are contentious due to the inherent limitations associated with either the instruments employed or the basic assumptions made for computing the specific-surface area of the soil. Hence, it becomes mandatory to evaluate the efficiency of these methodologies for determining specific-surface area of fine-grained soils. With this in view, different types of soils were considered in this study and their specific-surface area was determined, by following different methodologies, and the results were evaluated critically. In addition, attempts were made to develop relationships between the basic properties of fine-grained soils (viz., liquid limit, cation-exchange capacity, activity, and free swell index) and the specific-surface area. These relationships will be of immense help to the practicing engineers and research fraternity.

Keywords

Fine-grained soilSpecific-surface areaGas pycnometerBET techniqueEGME methodMB dye methodMercury intrusion porosimetry

Nomenclature

β

a constant parameter

δ

contact angle between the soil and mercury

λ

wavelength of UV-light

ρHe

density of the soil measured with He

\( \rho _{{{\text{N}}_{{\text{2}}} }} \)

density of the soil measured with N2

a

absorbance

amax

maximum absorbance

A

activity of the soil

AMB

area covered by each molecule of the Methylene blue (MB) dye

Amol

area covered by each N2 molecule

Av

Avogadro’s number

b

a parameter

C

concentration of the MB dye

Ce

concentration of the MB dye solution after 24 h

CEC

cation-exchange capacity

Ci

initial concentration of the MB dye solution

CMBET

a constant

Copt

optimal amount of the MB absorbed on the soil

Cse

amount of the MB absorbed on the soil after 24 h

Csi

amount of the MB, initially added to soil

G

specific gravity of the soil

l/s

liquid-solid ratio

LL

liquid limit of the soil

MWMB

molecular weight of the MB dye

p

applied pressure

P

pressure of N2 gas

P/P0

relative pressure

P0

saturation vapor pressure of N2

PI

plasticity-index of the soil

PL

plastic limit of the soil

S

specific-surface area

Sair

specific-surface area of the soil obtained from air-adsorption method

Sext

external specific-surface area of the soil

Sint

internal specific-surface area of the soil

SL

shrinkage limit of the soil

SLM

specific-surface area of the soil obtained from Langmuir isotherm

SMB

specific-surface area, obtained from MB absorption technique

SMBET

specific-surface area, obtained from the multi-point BET isotherm

SMIP

specific-surface area, obtained from mercury intrusion porosimetry

FSI

free swell index of the soil

SSBET

specific-surface area, obtained from the single-point BET isotherm

Stotal

total specific-surface area of the soil

T

surface tension of Hg

t

time

V

cumulative volume of mercury intruded into the soil

Va

volume of N2 adsorbed at pressure P

Vair

air-adsorption capacity of the soil

VLm

volume of N2 required for mono-layer formation as per Langmuir isotherm

Vmax

maximum volume of Hg intruded in the sample

VMBET

volume of N2 required for mono-layer formation as per multi-point BET isotherm

Vmol

volume of N2 molecule

W

weight of the soil

Wc

amount of EMGE absorbed on the sample for mono-layer formation

WEGME

amount of EGME absorbed on the sample

wEGME

amount of EGME required to cover per square meter of Bentonite

Copyright information

© Springer Science+Business Media B.V. 2007

Authors and Affiliations

  • D. N. Arnepalli
    • 1
  • S. Shanthakumar
    • 2
  • B. Hanumantha Rao
    • 2
  • D. N. Singh
    • 2
  1. 1.Department of Civil EngineeringQueen’s UniversityKingstonCanada
  2. 2.Department of Civil EngineeringIndian Institute of Technology BombayMumbaiIndia