Influence of bedding and jointing sand on the shear strength characteristics of Interlocking Paver Blocks - bedding sand interface

Shear stress behaviour is one of the predominant characteristics which influence the performance of Interlocking Concrete Block Pavement. The primary objective of the present study is to find the influence of bedding sand and jointing sand on the interface shear stress behaviour of Interlocking Paver Blocks (IPB) and bedding sand. The shear stress behaviour was studied using a large-scale direct shear test. Three grades of bedding sand were involved in the study. PLAXIS software was used to simulate the laboratory test results and the accuracy of the test results was statistically validated. In order to avoid tedious experimental studies, further analysis was executed using PLAXIS software. Eight gradations of jointing sand were analysed using numerical modelling to interpret its influence on the interface shear stress behaviour. The actual shear stress due to the traffic load for 50 million standard axles was estimated using IITPAVE software and the respective interface shear strength was calculated from the experimental results to ensure that the interface shear strength can resist the actual shear stress. Laboratory and numerical test results unveiled that the IPB when laid on Zone II bedding sand packed by Zone II>>2.36 jointing sand exhibited better interface shear stress behaviour.