The effect of bedding thickness on interlocking block pavement performance

ABSTRACT

An interlocking block pavement (IBP) comprises discrete blocks, joints, bedding sand, and base and subbase layers. The thickness of the bedding sand layer gives significant impact on IBP performance. However, previous laboratory model tests have often overlooked the geotechnical properties of paving materials and the deformation characteristics of the sublayers, leading to conflicting recommendations regarding appropriate thickness. This study performed laboratory tests on IBP models with varying bedding thicknesses (30, 50, and 80 mm), considering the geotechnical properties (relative density, shear strength, and stress–strain behaviour) of the paving materials. In addition, a novel two-dimensional (2D) model chamber with a transparent wall was designed for particle image velocimetry (PIV) analysis to assess the overall deformation of the sublayers. The test results demonstrated that a bedding thickness of 50 mm exhibited higher load-dispersion ability, allowing the blocks to settle and rotate appropriately and achieving a full interlocking effect. Consequently, the deflection in the sublayer was distributed over a wide area at shallow depths. However, a bedding thickness of 30 mm provided a better performance in terms of resistance to deflection, imposing a higher stress on the base layer.

KEYWORDS:

• Interlocking block pavements (IBPs)
• interlocking effect
• bedding sand thickness
• block thickness
• relative density
• particle image velocimetry (PIV) analysis

Acknowledgment

The authors wish to express their gratitude for the support.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was supported by the Institute of Construction and Environmental Engineering (ICEE) at Seoul National University.