TY - JOUR
T1 - Effect of Mellowing and Coal Fly Ash Addition on Behavior of Sulfate-Rich Dispersive Clay after Lime Stabilization
AU - Consoli, Nilo Cesar
AU - Bittar Marin, Eduardo José
AU - Quiñónez Samaniego, Rubén Alejandro
AU - Scheuermann Filho, Hugo Carlos
AU - Miranda, Tiago
AU - Cristelo, Nuno
PY - 2019/6/1
Y1 - 2019/6/1
N2 - Dispersivity and swelling induced by the formation of expansive minerals are deleterious phenomena that can be observed in natural and treated soils. The former is common among sodium-rich soils that are characterized by the deflocculation of the soil's particles in contact with water. The latter happens due to the growth and hydration of calcium sulfoaluminate minerals as expected in sulfate-rich soils treated with calcium-based stabilizers. The present study assesses the behavior of the Paraguayan sulfate-rich, dispersive as well as expansive, clayey soil after lime stabilization based on an extensive experimental work, which includes unconfined compression, pulse velocity, durability, and free swell tests. This work was designed employing a fractional factorial design in the selection of the experimental runs that enabled statistical evaluation of the influence of the dry unit weight, lime and fly ash content, curing period, mellowing process, and molding moisture content. Results showed that the addition of fly ash, followed by the dry unit weight, were the most influential factors regarding the treated soil's response in performed tests. In addition, mellowing proved to be essential in reducing the volumetric variation verified in the swelling tests. Also, scanning electron microscopy analysis revealed that ettringite formation was less pronounced when fly ash was added.
AB - Dispersivity and swelling induced by the formation of expansive minerals are deleterious phenomena that can be observed in natural and treated soils. The former is common among sodium-rich soils that are characterized by the deflocculation of the soil's particles in contact with water. The latter happens due to the growth and hydration of calcium sulfoaluminate minerals as expected in sulfate-rich soils treated with calcium-based stabilizers. The present study assesses the behavior of the Paraguayan sulfate-rich, dispersive as well as expansive, clayey soil after lime stabilization based on an extensive experimental work, which includes unconfined compression, pulse velocity, durability, and free swell tests. This work was designed employing a fractional factorial design in the selection of the experimental runs that enabled statistical evaluation of the influence of the dry unit weight, lime and fly ash content, curing period, mellowing process, and molding moisture content. Results showed that the addition of fly ash, followed by the dry unit weight, were the most influential factors regarding the treated soil's response in performed tests. In addition, mellowing proved to be essential in reducing the volumetric variation verified in the swelling tests. Also, scanning electron microscopy analysis revealed that ettringite formation was less pronounced when fly ash was added.
KW - Dispersive clay
KW - Durability
KW - Expansive minerals
KW - Laboratory tests
KW - Lime stabilization
KW - Strength
KW - Sulfate
UR - http://www.scopus.com/inward/record.url?scp=85063405768&partnerID=8YFLogxK
U2 - 10.1061/(ASCE)MT.1943-5533.0002699
DO - 10.1061/(ASCE)MT.1943-5533.0002699
M3 - Article
AN - SCOPUS:85063405768
SN - 0899-1561
VL - 31
JO - Journal of Materials in Civil Engineering
JF - Journal of Materials in Civil Engineering
IS - 6
M1 - 04019071
ER -