Evaluation of Interface Shear Strength Properties of Geogrid-Reinforced Construction and Demolition Materials Using a Modified Large-Scale Direct Shear Testing Apparatus

Abstract

The interface shear strength properties of geogrid-reinforced Construction and Demolition (C&D) aggregates were determined using a modified large scale direct shear test (DST) apparatus. Comparisons were made between the results of the various C&D aggregates reinforced with biaxial and triaxial geogrids as well as with the unreinforced aggregates by means of the modified and conventional DST methods. The modified DST method employed, sought to increase interlocking between the C&D aggregates with the geogrids and thus ascertains the true interface shear strength properties of the recycled demolition aggregates. Biaxial and triaxial geogrids were used as the geogrid-reinforcement materials. The C&D aggregates tested with the DST were Recycled Concrete Aggregate (RCA), Crushed Brick (CB) and Reclaimed Asphalt Pavement (RAP). The modified DST results indicated that the interface shear strength properties of the geogrid-reinforced C&D aggregates were higher than that of the conventional test method as well as the respective unreinforced materials. Geogrid-reinforced RCA was found to have the highest interface peak and residual shear strength property of the C&D materials. RAP was found to have the smallest interface shear strength properties of the C&D aggregates. The higher stiffness triaxial geogrid attained higher interface shear strength properties than that of the lower stiffness biaxial geogrid. The modified device also showed some increased measured interface coefficients compared to a conventional DST. The geogrid-reinforced recycled C&D aggregates was found to meet the peak and residual shear strength requirements for typical construction aggregates used in civil engineering applications.

Impact of highly weathered geology on pipe-jacking forces

“…The direct shear test has been used for various studies on soil-structure interfacial friction, ranging from fundamental soil mechanics (Jewell, 1986;Simoni and Houlsby, 2006) to its application on geotechnical engineering problems (Arulrajah et al, 2013;Iai and Luna, 2011;Kulhawy and Mayne, 1990). The suitability of using a direct shear test for investigating jacking forces was demonstrated by Staheli (2006), who conducted direct shear testing of sand-pipe interfaces, based on a customised shear box developed by Iscimen (2004).…”

Effect of geogrid reinforcement on flexible pavements

“…Arulrajah et al [14] studied the interface shear strength properties of geogrid-reinforced construction and demolition (C&D) aggregates using a modified large-scale direct shear test (DST) apparatus. The geogrids were biaxial and triaxial and the C&D aggregates were recycled concrete aggregate (RCA), crushed brick (CB), and reclaimed asphalt pavement (RAP).…”

Effect of geogrid reinforcement on the flexural behaviour of concrete pavements

“…This is because their openings' shape can provide the appropriate interlocking between the geogrid layer and the surrounding concrete. In addition, the triaxial geogrid proved that the tensile and shear strengths of concrete elements reinforced with this type of geogrid were improved in comparison with other geogrid types (Meski & Chahab, 2014;Arulrajah et al, 2014).…”

“…Geogrid products have several structural advantages making them a potential alternative of steel reinforcement for Portland cement concrete thin sections under relatively light loading conditions and Arulrajah et al, 2014). These advantages include a high tensile strength and excellent chemical resistance.…”