An experimental study on interlocking mechanisms in concrete block pavement

With the growing demand for interlocking concrete block pavements (ICBPs), extensive research has focused on their structural performance. However, studies investigating the interlocking effect, the primary load-bearing mechanism of ICBPs, remain limited. This study evaluates interlocking mechanisms through repeated loading, pull-out, and modified direct shear tests (MDSTs) on joints with relative densities of 55% and 78% and widths of 2 mm and 5 mm. Repeated loading tests showed enhanced deflection resistance and load-dispersion ability at 78% density and 2 mm width. Pull-out tests confirmed greater shear resistance under the same conditions, indicating the contribution of vertical interlocking. However, slip displacement during repeated loading was insufficient to induce dilatancy as observed in MDSTs, suggesting limited vertical interlocking under traffic loads. Dissipated stress analysis revealed rotational interlocking as dominant mechanism at 78% density, contributing nearly twice as much as vertical interlocking regardless of joint width. In contrast, at 55% density, dissipated stress was lower than pull-out shear resistance, implying reduced interlocking. Based on test results, a method was proposed to estimate stress dissipation owing to rotational interlocking using vertical interlocking data. These findings highlight the dominant role of rotational interlocking and underscore the importance of joint density in ensuring ICBP performance.