Effectiveness of connectors in geofoam block construction

This paper reports the results of shear resistance tests conducted on geofoam blocks with no connection, blocks connected with barbed connector plates, and blocks connected with polyurethane adhesive. In the first phase, tests were completed in a large direct shear box (430 mm L × 280 mm W) under normal pressures of 14.8 kPa, 29.6 kPa, and 74.1 kPa. In phase II, tests were conducted on 1200 mm L × 600 mm W specimens using a computer controlled actuator under normal pressures of 9.3 kPa, 18.1 kPa and 26.9 kPa. The measured values of the coefficient of friction between blocks were found to be consistent with the values reported in the literature and conservative in terms of commonly used design values. The test results show that the presence of barbed connector plates did not provide additional interface shear resistance; however polyurethane adhesive was successful in bonding the blocks together thus virtually eliminating horizontal sliding between the blocks. Blocks connected with barbed connector plates subject to repeated loading showed signs of decreased shear resistance during reloading, but did reach the peak shear resistance measured during initial loading.