Aggregate Properties Affecting Shear Strength and Permanent Deformation Characteristics of Unbound-Base Course Materials

Yong Hoon Byun, Bin Feng, Issam I.A. Qamhia, Erol Tutumluer

Research output: Contribution to journalArticle

Abstract

Resistance to permanent deformation is the primary performance indicator of unbound aggregate pavement layers. In relation to the applied wheel-load deviator stress, the shear strength property of a confined base/subbase controls the rate of permanent strain accumulation in that aggregate layer. The objective of this study was to quantify the impact of aggregate properties on the shear strength and permanent deformation characteristics of unbound aggregates. Sixteen different aggregates were studied in the laboratory for two different gradations: original quarry source and engineered midrange gradations. Aggregate specimens were prepared at these gradations to determine moisture-density relationships, and conduct monotonic and repeated load triaxial tests at the target maximum dry densities and optimal moisture contents. In addition, imaging-based aggregate particle shapes or morphological indices were obtained. The laboratory findings indicated that the particle size corresponded to 60% passing, and imaging-based angularity index contributed significantly to the increases in the shear strength properties of aggregates, which were also affected by density and moisture content. Permanent strain accumulations were primarily influenced by applied shear stress in relation to the shear strength of aggregates, and rutting model parameters obtained through regression analyses were influenced by applied stress, strength, and material properties. Further, an aggregate with plastic fines showed the highest permanent strain accumulation, hence clearly indicating the significant influence of plasticity of fines on the permanent strain accumulation.

Original languageEnglish (US)
Article number04019332
JournalJournal of Materials in Civil Engineering
Volume32
Issue number1
DOIs
StatePublished - Jan 1 2020

Fingerprint

Shear strength
Moisture
Imaging techniques
Quarries
Pavements
Plasticity
Shear stress
Loads (forces)
Materials properties
Wheels
Particle size
Plastics

Keywords

  • Base/subbase
  • Gradation
  • Permanent deformation
  • Shear strength
  • Unbound aggregates

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • Materials Science(all)
  • Mechanics of Materials

Cite this

Aggregate Properties Affecting Shear Strength and Permanent Deformation Characteristics of Unbound-Base Course Materials. / Byun, Yong Hoon; Feng, Bin; Qamhia, Issam I.A.; Tutumluer, Erol.

In: Journal of Materials in Civil Engineering, Vol. 32, No. 1, 04019332, 01.01.2020.

Research output: Contribution to journalArticle

@article{3212f236c41646a0a9bf839b179293e0,
title = "Aggregate Properties Affecting Shear Strength and Permanent Deformation Characteristics of Unbound-Base Course Materials",
abstract = "Resistance to permanent deformation is the primary performance indicator of unbound aggregate pavement layers. In relation to the applied wheel-load deviator stress, the shear strength property of a confined base/subbase controls the rate of permanent strain accumulation in that aggregate layer. The objective of this study was to quantify the impact of aggregate properties on the shear strength and permanent deformation characteristics of unbound aggregates. Sixteen different aggregates were studied in the laboratory for two different gradations: original quarry source and engineered midrange gradations. Aggregate specimens were prepared at these gradations to determine moisture-density relationships, and conduct monotonic and repeated load triaxial tests at the target maximum dry densities and optimal moisture contents. In addition, imaging-based aggregate particle shapes or morphological indices were obtained. The laboratory findings indicated that the particle size corresponded to 60{\%} passing, and imaging-based angularity index contributed significantly to the increases in the shear strength properties of aggregates, which were also affected by density and moisture content. Permanent strain accumulations were primarily influenced by applied shear stress in relation to the shear strength of aggregates, and rutting model parameters obtained through regression analyses were influenced by applied stress, strength, and material properties. Further, an aggregate with plastic fines showed the highest permanent strain accumulation, hence clearly indicating the significant influence of plasticity of fines on the permanent strain accumulation.",
keywords = "Base/subbase, Gradation, Permanent deformation, Shear strength, Unbound aggregates",
author = "Byun, {Yong Hoon} and Bin Feng and Qamhia, {Issam I.A.} and Erol Tutumluer",
year = "2020",
month = "1",
day = "1",
doi = "10.1061/(ASCE)MT.1943-5533.0003000",
language = "English (US)",
volume = "32",
journal = "Journal of Materials in Civil Engineering",
issn = "0899-1561",
publisher = "American Society of Civil Engineers (ASCE)",
number = "1",

}

TY - JOUR

T1 - Aggregate Properties Affecting Shear Strength and Permanent Deformation Characteristics of Unbound-Base Course Materials

AU - Byun, Yong Hoon

AU - Feng, Bin

AU - Qamhia, Issam I.A.

AU - Tutumluer, Erol

PY - 2020/1/1

Y1 - 2020/1/1

N2 - Resistance to permanent deformation is the primary performance indicator of unbound aggregate pavement layers. In relation to the applied wheel-load deviator stress, the shear strength property of a confined base/subbase controls the rate of permanent strain accumulation in that aggregate layer. The objective of this study was to quantify the impact of aggregate properties on the shear strength and permanent deformation characteristics of unbound aggregates. Sixteen different aggregates were studied in the laboratory for two different gradations: original quarry source and engineered midrange gradations. Aggregate specimens were prepared at these gradations to determine moisture-density relationships, and conduct monotonic and repeated load triaxial tests at the target maximum dry densities and optimal moisture contents. In addition, imaging-based aggregate particle shapes or morphological indices were obtained. The laboratory findings indicated that the particle size corresponded to 60% passing, and imaging-based angularity index contributed significantly to the increases in the shear strength properties of aggregates, which were also affected by density and moisture content. Permanent strain accumulations were primarily influenced by applied shear stress in relation to the shear strength of aggregates, and rutting model parameters obtained through regression analyses were influenced by applied stress, strength, and material properties. Further, an aggregate with plastic fines showed the highest permanent strain accumulation, hence clearly indicating the significant influence of plasticity of fines on the permanent strain accumulation.

AB - Resistance to permanent deformation is the primary performance indicator of unbound aggregate pavement layers. In relation to the applied wheel-load deviator stress, the shear strength property of a confined base/subbase controls the rate of permanent strain accumulation in that aggregate layer. The objective of this study was to quantify the impact of aggregate properties on the shear strength and permanent deformation characteristics of unbound aggregates. Sixteen different aggregates were studied in the laboratory for two different gradations: original quarry source and engineered midrange gradations. Aggregate specimens were prepared at these gradations to determine moisture-density relationships, and conduct monotonic and repeated load triaxial tests at the target maximum dry densities and optimal moisture contents. In addition, imaging-based aggregate particle shapes or morphological indices were obtained. The laboratory findings indicated that the particle size corresponded to 60% passing, and imaging-based angularity index contributed significantly to the increases in the shear strength properties of aggregates, which were also affected by density and moisture content. Permanent strain accumulations were primarily influenced by applied shear stress in relation to the shear strength of aggregates, and rutting model parameters obtained through regression analyses were influenced by applied stress, strength, and material properties. Further, an aggregate with plastic fines showed the highest permanent strain accumulation, hence clearly indicating the significant influence of plasticity of fines on the permanent strain accumulation.

KW - Base/subbase

KW - Gradation

KW - Permanent deformation

KW - Shear strength

KW - Unbound aggregates

UR - http://www.scopus.com/inward/record.url?scp=85074543574&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85074543574&partnerID=8YFLogxK

U2 - 10.1061/(ASCE)MT.1943-5533.0003000

DO - 10.1061/(ASCE)MT.1943-5533.0003000

M3 - Article

AN - SCOPUS:85074543574

VL - 32

JO - Journal of Materials in Civil Engineering

JF - Journal of Materials in Civil Engineering

SN - 0899-1561

IS - 1

M1 - 04019332

ER -