Performance of underside shaped concrete blocks for pavement

Abstract

This study presents an innovative concrete block pavement (CBP) of rectangular blocks with grooves and web on the underside of the underside shaped concrete block (USCB). This new concrete block concept intends to address known causes of failure for CBP due to vertical, horizontal and repetitive traffic loading. Interaction between CBP and underlying bedding sand layer may lead to significant pavement deformation due to vertical traffic loading. The USCB provides an additional underside mechanical interlocking, compared with traditional rectangular concrete block. Twelve USCB with different groove depths (15 mm, 25 mm, and 35 mm) and four different bottom shapes (Shell – Rectangular (Shell–R), Trench Groove – Triangular (TG–T), Trench Groove – 2 Rectangular (TG–2R), and Trench Groove – 3 Rectangular (TG–3R)) were prepared. These USCB were mechanically tested to investigate the effects of groove depth, groove volume, and groove shape on their mechanical properties. To investigate their interlocking performance, a series of push-in loading test, pull-out loading test, horizontal loading test, and accelerated trafficking test were conducted using the Highway Accelerated Loading Instrument (HALI). A control pavement and with only stretcher bond laying pattern was built to allow for comparisons. The results indicate that triangular grooves exhibit promising compressive strength while rectangular grooves performed better in flexural, with the increase up to 25 % respectively when compared to control block. The optimum USCB groove depth is found at 15 mm and the Shell USCB has the best mechanical properties and resilience under all conditions due to their unique shape. The function of the grooves and web as spike has enhanced the mechanical properties of USCB and improved the interlocking mechanism between CBP and its underlying bedding sand layer. The study shows that USCB is a highly potential concrete block that could enhance pavement performance.