Figure 11.
The horizontal axis gives displacement u from negative 2.5 to 7.5 millimetres. The vertical axis gives rotation delta from negative 45 to 45 degrees. The miniature concrete curve forms a loop, reaching about positive 36 degrees and negative 37 degrees. The epoxy sand coating curve at sigma v 60 kilopascals and D r 85 forms a similar loop, reaching about positive 37 degrees and negative 33 degrees. The dashed epoxy sand coating curve at sigma v 120 kilopascals and D r 75 increases to about 33 degrees, then decreases to about 28 degrees between 5 and 7.5 millimetres. A marked point indicates mechanical compliance near 2 millimetres and 0 degrees. The loading schematic labels horizontal stress sigma h 60 kilopascals, vertical stress sigma v, and horizontal displacement H, u.Constant normal load (CNL) interface tests: mobilised interface friction angle, , or friction coefficient, against shear displacement,