An Assessment of Resilient Modulus Testing: Internal and External Deflection Measurements

Camargo, Felipe; Benson, Craig H.; Edil, Tuncer B.

doi:10.1520/gtj20120077

Cited by 11 publications

(5 citation statements)

References 10 publications

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“…The SRM ratio increases consistently with the SRM calculated from the internal LVDTs. This observation is similar to those by Sawangsuriya et al (19) and Camargo et al (20). An SRM computed from an internal LVDT is believed to provide better accuracy than an SRM computed from an external LVDT because displacement measured from an internal LVDT can eliminate the errors resulting from machine compliance and end (bedding) effects (20,21).…”

Section: Saturation and Soil Suction Initializationsupporting

confidence: 85%

Effect of Matric Suction on Resilient Modulus for Compacted Recycled Base Course in Postcompaction State

Nokkaew

Tinjum

Likos

et al. 2014

Transportation Research Record: Journal of the Transportation R

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The demand for recycled material as the unbound base course in roadway construction has increased in recent decades because of the excellent mechanical properties of the recycled base course and inherent life-cycle benefits. However, concerns have been expressed about postconstruction changes in the resilient modulus (Mr) caused by moisture variation. This study investigated the relationship of Mr to soil matric suction (ψ) at an in-service stress state for recycled asphalt pavement, recycled pavement material, and recycled concrete aggregate compared with crushed limestone as a conventional base course control. Resilient modulus tests were conducted in accordance with NCHRP Project 1–28A Procedure 1a. Equipment modifications allowed for an applied ψ ranging from 1.5 kPa to 65 kPa during testing. A proposed model incorporated parameters from the soil–water characteristic curve to predict a summary resilient modulus (SRM), that is, the in-service Mr at a representative field stress state. The SRM increased with increasing ψ for all compacted base courses studied. An SRM ratio, defined as the ratio of the SRM at a particular ψ to the as-compacted SRM at optimum water content, was empirically quantified. The modulus ratio increased linearly with logarithmic ψ for the studied recycled and natural aggregates. The findings indicate that the Mr–ψ relationship is highly relevant for predicting in-service performance of pavement layers.

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Section: Saturation and Soil Suction Initializationsupporting

confidence: 85%

Effect of Matric Suction on Resilient Modulus for Compacted Recycled Base Course in Postcompaction State

Nokkaew

Tinjum

Likos

et al. 2014

Transportation Research Record: Journal of the Transportation R

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“…Design agencies are moving to adopt M-EPDG, which requires the use of a modulus based on internal deflection measurements. Additionally, using internal LVDTs eliminates the error resulting from machine compliance and end effects (Camargo, Benson, & Edil, 2012;NCHRP, 2004). Therefore, M R obtained from deformations measured by the internal Downloaded by [University of Leeds] at 17:02 04 October 2015…”

Section: Methodsmentioning

confidence: 99%

Climatic effect on resilient modulus of recycled unbound aggregates

Soleimanbeigi

Shedivy

Tinjum

et al. 2015

Road Materials and Pavement Design

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The effect of temperature on plastic strain and resilient modulus (M R ) of different sources of recycled asphalt pavement (RAP) and recycled concrete aggregate (RCA) was evaluated from the results of laboratory temperature-controlled M R tests, with a conventional Class 5 aggregate serving as the control. Freeze-thaw tests were also conducted on samples of RAP and RCA. Five years (spring-summer-fall-winter) of field falling weight deflectometer (FWD) tests were conducted on three pavement sections with RAP, RCA, and Class 5 as the unbound base course. Laboratory test results showed that temperature rise increased plastic strain and reduced M R of RAP under cyclic loads but had a negligible effect on plastic strain and M R of RCA. Freeze-thaw cycles steadily reduced the M R of RAP; however, long-term freeze-thaw cycles increased the M R of RCA. Thermal preloading reduced the plastic strain and increased the M R of the compacted RAP. Construction of a pavement system made with RAP is thus recommended during warm seasons to induce thermal preloading. The elastic modulus backcalculated from the FWD tests did not show a consistent trend with respect to temperature change. No significant change on elastic modulus of RAP, RCA, and Class 5 aggregates due to freeze-thaw cycles was observed over five years.

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“…The test conditions are also particularly important when testing the deformation of saturated samples [1]. The resilient modulus determined from the internal and external deflection measurements may differ significantly [21]. The difference is less than 50% for unbound materials and subgrade soils, but it is higher for stiff, stabilised materials.…”

Section: Introductionmentioning

confidence: 99%

Resilient Response of Cement-Treated Coarse Post-Glacial Soil to Cyclic Load

2021

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Stabilisation with cement is an effective way to increase the stiffness of base and subbase layers and to improve the rutting of subgrade. The aim of the study is to investigate the effect of different percentages of cement additives (1.5%, 3.0%, 4.5% and 6.0%) on the resilient modulus of coarse-grained soil used on road foundations. The influence of the compaction method, the standard Proctor and the modified Proctor, as well as the sample curing time is analysed. The cement addition significantly increases the resilient modulus and reduces the resilient axial strain. Extending the curing time from 7 to 28 days also improves the resilient modulus. The change in the compaction energy from standard to modified does not increase the resilient modulus of the stabilised gravelly sand due to its compaction characteristics. The test results of the resilient modulus of the gravelly sand stabilised with cement indicate the possibility of using it as a material for the road base and subbase due to meeting the AASHTO requirements. However, the non-stabilised gravelly sand does not meet the above requirements. It has been sheared during cyclic tests at the first load sequence, regardless of the compaction method.

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An Assessment of Resilient Modulus Testing: Internal and External Deflection Measurements

Cited by 11 publications

References 10 publications

Effect of Matric Suction on Resilient Modulus for Compacted Recycled Base Course in Postcompaction State

Effect of Matric Suction on Resilient Modulus for Compacted Recycled Base Course in Postcompaction State

Climatic effect on resilient modulus of recycled unbound aggregates

Resilient Response of Cement-Treated Coarse Post-Glacial Soil to Cyclic Load

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