Field investigation of material layer properties for emulsion-treated base layer application in low-volume roads

ABSTRACT

The study presents the determination of pavement design input parameters-structural layer coefficients and back-calculated layer moduli for Emulsion-Treated Base (ETB) layer materials in a Low-Volume Road (LVR) application. Seven test sections were constructed on a stretch of LVR with varying emulsion contents and 50% Recycled Asphalt Pavement (RAP) aggregate incorporation in ETB mixes. Structural performance of the test sections was periodically observed using a Benkelman Beam Deflectometer (BBD) and the data was used for the estimation of the structural layer coefficient of ETB, based on the effective structural number of the pavement. The deflection bowl data of the test sections were also captured using a Falling Weight Deflectometer (FWD) and the modulus of ETB layer was back-calculated using a back-calculation software. The study proposes a structural layer coefficient of 0.23–0.29 and back-calculated moduli of 578–919 MPa for ETB mixes characterised by Indirect Tensile Strength (ITS) values ranging between 140 kPa and 245 kPa. Traffic level-based ETB mix specifications are also proposed in the study, which enables a mix designer to proportion the mix for a selected design traffic level. For a design traffic level of 1 million standard axles, the target dry ITS specification was found to be 188 MPa.

KEYWORDS:

• Low-volume road
• emulsion-treated base
• structural layer coefficient
• back-calculated moduli
• indirect tensile strength

Acknowledgements

Authors wish to acknowledge the Alappuzha Division of Local Self Government Department (LSGD), Government of Kerala, for providing the financial assistance and technical support to construct the test sections. Authors also wish to acknowledge the Science and Engineering Research Board (SERB) for providing the financial support for conducting the performance evaluation of the test sections and the Kerala Infrastructure Investment Fund Board (KIIFB) for offering the technical support necessary for the data collection using Falling Weight Deflectometer (FWD).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Alappuzha Division of Local Self Government Department; Science and Engineering Research Board; Kerala Infrastructure Investment Fund Board.